sounds complicated but in principle is fairly straightforward: the diagram shows this far more simply
than reams of text.
PAW
TECHNICAL
GUIDE
A Technical guide to:
The Professional Adventure Writer
A graphic adventure writing system for the Sinclair Spectrum computers
Converted to Word Format by Pablo Contreras
If Gilsoft want to sue me for this, please don't because:
a) I'm a great fan of your product
and want to encourage its use
b) Nobody would buy it now anyway
c) I did buy PAW when it came out
d) I'm very skint
Although I've tried to keep errors
out, I am only human so please e-mail me any corrections you may
find - my e-mail address is
pablo@patrol.i-way.co.uk.
¸ 1986 Gilsoft International Ltd.
Program: T.J. Gilberts, G.Yeandle and
P.Wade
Graphics: D.Peeke, K.Maddocks and
A.Williams
Manuals: T.J. Gilberts
All Rights reserved. No part of
this publication may be copied, loaned, hired or reproduced in
any form
whatsoever including electronic
retrieval systems without the prior written consent of the
authors and
Gilsoft International Ltd.
The above notice does not apply to
the 'run time' routines appended to, and which form a part of, a
saved game which you are free to
distribute any way you wish in that form. All we would request is
that
you credit the use of the
Professional Adventure Writer somewhere within the game.
Acknowledgement
Thanks to Howard and Pam for their
forbearance. Phil for his 'comments', Greame for his ideas, Dicon
et al for the graphics and all our
customers for their support and suggestions.
Overview
PAW can be divided into three main
functional areas thus:
1/ The Database
The database is the collection of
tables organised in a logical manner, which contain all the
information
to define an adventure game. This
database is initially set up to contain a minimum of entries
which
will probably be needed in every
game. There is usually one entry in a table to simplify the
operations
of the system. The database may
utilise the additional sideways RAM pages of a 128K Spectrum.
2/ The Editor
This consists of a two level menu
system i.e. most functions on the main menu present a sub-menu
from
which all facilities can be selected.
All facilities are set either from a command line as part of the
sub-
menu option or in response to a
prompt. This combination of menu and command line has been found
to be the most efficient both for the
beginner and the more experienced user.
3/ The Interpreter
The real heart of PAW is contained
in this section of the program. The next chapter deals with the
operation of the interpreter in
detail, but it essentially fetches commands from the player and
uses the
information contained in the database
to decode and respond to those commands.
The sheer size of PAW precludes it
being held entirely within the main memory area. On a 128K
Spectrum the majority of the code is
held as overlays on a sideways RAM page and transferred into the
main area whenever required. A
similar system is used on a 48K Spectrum by holdin three of the
overlays in free memory until the
area of memory used is overwritten. If the sideways RAM page is
initialised on a 128K or the memory
area overwritten on a 48K, an attempt to select an option not in
the
current overlay will result in PAW
attempting to lead the requisite overlay from cassette (or disc).
The
main menu and overlay system gives an
overhead of approximately 4K which is unavailable to PAW for
the database. About 10K is consumed
by the interpreter and its workspace (e.g. Ramsave buffer, input
and wordwrap buffers etc.) This
leaves approximately 27K for the database, plus 5 pages of 16K
each,
on a 128K Spectrum (a total of about
117K). This is maximised by the inclusion of a text compressor
which introduces an overhead of 222
bytes (for an expansion dictionary) this giving about 40%
effective
text compression. On an average text
only game on the 48K Spectrum this provides an effective
addition of 8K of database space
(i.e. a total of 35K).
The Interpreter
The following description of the
interpreter should be read in conjunction with the flowcharts
provided
overleaf.
Initialise
The background colours and character
set are selected - the screen isn't cleared as this always occurs
upon describing location zero. The
flags are all zeroed except for; flag 37, the number of objects
conveyable, which is set to 4; flag
52, the maximum weight of objects conveyable, which is set to 10;
flags 46 & 47, the current
pronoun ("IT" usually), which are set to 255 (no
pronoun) and glag 1 which
is set to be the number of objects
carried but not worn. Note that clearing the flags has the effect
that
the game always starts at location
zero. This is because flag 38, the current location of the
player, is
now zero.
Describe Current Location
If flag 2 is non zero it is
decremented (reduced by 1). If it is dark (flag 0 is non zero)
and flag 3 is non
zero then flag 3 is decremented. If
it is dark, flag 4 is non zero and object 0 (the source of light)
is
absent, then flag 4 is decremented.
The screen is cleared if the current screen mode (contents of flag 40) is not 1.
If it is dark, and Object 0 is
absent, then System message 0 (referred to as SM0 - "It's
too dark to see
anything") is displayed.
Otherwise any picture present for the location is drawn and the
location
description displayed without a
NEWLINE.
Search Process Table 1
Flowchart 2 and the next section
describe the scanning of a process table. Process table 1 is used
mainly to contain the entries to add
extra information to the current location description. E.g.
details of
open doors, objects present etc. It
will also contain a PROTECT action, when using screen mode 4, to
set the screen line for text to
scroll under.
We now enter the main loop of the
interpreter which deals with teach time fame (i.e. each phrase
extracted or each timeout on input
which occurs) and the response to players commands.
Search Process Table 2
This contains the main control for
PAW's turn at the game. It is used to implement the movements and
actions of PSI's, the uncontrolled
events such as bridges collapsing, and so on.
Get Phrase
If flags 5 to 8 are non zero they are
decremented. If it is dark (Flag 0 is non zero) and flag 9 is non
zero
then it is decremented. If it is dark
and flag 10 is non zero is is decremented if object 0 is absent.
The parser is called to extract a
phrase and convert it into a logical sentence - LS. If the input
buffer is
empty, a new input line is obtained
from the player by printing a prompt and making a call to the
input
routine. The prompt will be the
system message whose number is contained in flag 42 - a value of
0 will
select one of the system messages
2,3,4 or 5 in the ration 30:30:30:10 respectively.
If the timeout option is selected,
by making flag 48 contain a value greater than zero, then the
input
routine might time out. In this case
SM35 ("Time passes.") is displayed and a return made to
scan
process 2 again.
A phrase is extracted and
converted into the logical sentence; by converting any words
present, that are
in the vocabulary, into their word
value and placing them in the required flags.
If no valid phrase can be found
then SM6 ("I couldn't understand any of that") is
displayed, and a
return made to scan process 2.
Search Response Table
Turns (flag 31 and 32), which is the
number of valid phrases extracted by the parser, is increased by
one. Two flags area used to allow 256
lots of 256 turns (i.e. 65536).
The Response table is then
scanned, for an entry which matches the Verb and Noun1 of the
current LS,
using the process table routines
detailed below.
If it is successful in carrying
out an action (i.e. If PAW executes at least one action other
than
NOTDONE) then a return is made to
scan process table 2.
Search the Connections Table
A search is made of the connections
table entry for the current location, for a word which matches
the
current LS Verb. If one is found then
the players current location (flag 38) is set to be the number
associated with the word. Then a
return is made to describe the current location. Otherwise PAW
prints SM8 ("I can't go in that
direction") if the current LS Verb has a word value less
than 14 or SM7
("I can't do that") if it
does not. In both cases a return is made to scan process table 2.
Flowchart 1
/-------\ | Start | \-------/ | +----------+ |Initialise| +----------+ | +---\ | |D >------------+---------------------------------------+ +---/ | | +-----------+ | |Describe | | |Location | | |Process 1 | | +-----------+ | | | +-------------------------| | | | | | +-----------+ | | |Process 2 | | | |Get Phrase | | | +-----------+ | | | | | /-\ | | No /---- ----\ Yes | ^ +------< Found? >-------+ | | | \----\-/----/ | ^ | | | | | /-\ +-----------+ | | No /---- ----\ Yes |TURNS+1 | | | +-< Timeout? >----+ |Search | | | | \---- ----/ | |Response | | | | \-/ | +-----------+ | | | | | | | /------------/ /----------/ | | | |SM6 | |SM35 | | | | |"I don't | |"Time | | | | |"Understand"| |Passes.." | | | | /------------/ /----------/ /-\ | | | | Yes /---- ----\ No | +------+----------------+--<------< Done? >-----+ ^ | \----\-/----/ | | | | | | +-----------+ | | |Search | | | |Connection | | | |Table | | | +-----------+ | | | | | /-\ | | No /---- ----\ Yes | | +-----------------------< Found? >----+ | | \----\-/----/ | /-\ | /---- ----\ | +--------< Verb<14? >-----------+ | | \----\-/----/ | | | | | /----------/ /-----------/ | |SM8 | |SM7 | | |"Can't | |"Can't go | | |do that" | |that way" | | /----------/ /-----------/ | | | +------+---------------<------------------+
Flowchart 2
/-------\ | Start | \-------/ | +-------------------------------------+ | | /-\ | No /---- ----\ | +------------------| | \----\-/----/ ^ | | Yes | | /----/-\----\ Yes | | ----------------+ | | \----\-/----/ | ^ | | No /----/-\----\ No | | | < Verb Match? >------+ | | \----\-/----/ | | | | Yes ^ | | /----/-\----\ No | | | < Noun Match? >------+ | | \----\-/----/ | | | | Yes ^ | +-----------------------+----<--------+-+ | | | | | /----/-\-----\ No | | | -----------------------------+ | | \----\-/-----/ ^ | | | Yes | | | | | ^ | No /----/-\-----\ Yes | | | +---------< Condition? >---------------+ | | | | \----\-/-----/ | ^ | | | | | | | +-----------+ /----/-\----\ No | | | | Do Action | < Succeed? >------+ | | +-----------+ \----\-/----/ | | | | Yes | | /----/-\----\ Yes +---\ | | | < DESC? >-------+ D > | | | \----\-/----/ +---/ | | | | No | | | /----/-\----\ No | | +-< Exit? >---------------------------------+---------------+ | \----\-/----/ | +--------+ | /-------\ | End | \-------/
Scan a Process Table
Response is a process table (Note
that any sub-processes which are called from within Response
exhibit
the same features), so it will also
be scanned by this section of PAW> The difference of course is
that
PAW tries to match the Verb and Noun1
of the logical sentence in a Response table.
Essentially PAW will look at each
entry in the table until it is exhausted - the table of entries,
not
PAW! Assuming there is an entry, it
will, if in Response, ensure the Verb and Noun match those of the
LS. The use of the words
"*" and "_", as either the Verb or the Noun,
will cause a match with any word
in that part of the logical sentence.
Thus entries in Response of "* *", "_ _", and
combinations of same,
will cause a trigger of the entry no
matter what the LS. This feature must be used in any table which
will be called by both a Response and
a Process table. If in a Process the Verb and Noun will match
anyway, no matter what the logical
sentence.
PAW will then look at each CondAct
in turn; if it is a condition, which succeeds, then PAW will look
at the next condact. Otherwise it
will drop out of the current condact list and look at the next
entry, if
present, in the table - an exception
to this is the CondAct QUIT which, if it fails, will drop out of
the
table completely - this is not shown
in flowchart 2 for clarity. If it is an action it will be carried
out.
Actions can be divided into five main
groups:
1/ Desc; which will completely
exit the execution of all tables (i.e. even if in a 10th level
sub-process)
and jump to describe the current
location.
2/ END: (a group on its own) which
will completely exit the execution of all tables and jump to
initialise a new game.
3/ Exit; any action which will
stop processing of the current table and exit to the calling
table (or back
to the main loop if in Response,
Process 1 or 2). E.g. INVEN, DONE etc.
4/ Conditional Exit; any action
which will stop processing of the current table and exit to the
calling
table (or back to the main loop if in
Response, Process 1 or 2) if it fails to do its required
function. E.g.
GET, PUTIN etc. Otherwise it will
continue with the next CondAct.
5/ Normal; any action which
carries out its function, and allows PAW to continue looking at
the next
CondAct in the current entry. E.g.
COPYFF, PLUS etc.
It may be seen that QUIT acts like
a type 4 action, but is still a condition, so its a CondAct! The
summary of CondActs at the end of
this book shows which type each Action is.
The CondActs
There now follows a detailed
description of each CondAct. They are divided into groups
according to
the subject they deal with in PAW;
such as flags, objects etc and give some hints as to a possible
use.
Several abbreviations are used in the descriptions as follows.
locno. Is a valid location number.
locno+ is a valid location number
or; 252 (not-created), 253 (worn), 254 (carried) and 255 which is
converted into the current location
of the player.
mesno. is a valid message.
sysno. is a valid system message
flagno. is any flag (0 to 255).
procno. is a valid sub-process number.
word is word of the required type,
which is present in the vocabulary, or "_" which
ensures no-word -
not an anymatch as normal.
value is a value from 0 to 255.
Conditions
There are four conditions which deal
with testing the location of the player as follows;
AT locno.
Succeeds if the current location is
the same as locno.
NOTAT locno.
Succeeds if the current location is
different to locno.
ACGT locno.
Succeeds if the current location is
greater than locno.
ATLT locno.
Succeeds if the current location is
less than locno.
There are eight conditions which deal with the current location of an object;
PRESENT objno.
Succeeds if Object objno. is carried,
worn, or at the current location.
ABSENT objno.
Succeeds if Object objno. is not
carried, not worn and not at the current location.
WORN objno.
Succeeds if object objno. is worn.
NOTWORN objno.
Succeeds if Object objno. is carried.
CARRIED objno.
Succeeds if Object objno. is carried.
NOTCARR objno.
Succeeds if Object objno. is not
carried.
ISAT objno. locno+
Succeeds if Object objno. is not at
Location locno.
ISNOTAT objno. locno+
Succeeds if Object objno. is not at
Location locno.
There are eight conditions which deal with the value and comparison of flags;
ZERO flagno.
Succeeds if Flag flagno. is set to
zero.
NOTZERO flagno.
Succeeds if Flag flagno. is not set
to zero.
EQ flagno. value
Succeeds if Flag flagno. is equal to
value.
NOTEQ flagno. value
Succeeds if Flag flagno. is not equal
to value.
GT flagno. value
Succeeds if Flag flagno. is greater
than value.
LT flagno. value
Succeeds if Flag flagno. is set to
less than value.
SAME flagno1 flagno2
Succeeds if Flag flagno1 has the same
value as Flag flagno2.
NOTSAME flagno1 flagno2
Succeeds if Flag flagno1 does not
have the same value as Flag flagno2.
There are five conditions to check
for an extended logical sentence. It is best to use these
conditions
only if the specific word (or absence
of word using "_") is needed to differentiate a
situation. This
allows greater flexibility in the
commands understod by the entry.
ADJECT1 word
Succeeds if the first noun's
adjective in the current LS is word.
ADVERB word
Succeeds if the adverb in the current
LS is word.
PREP word
Succeeds if the preposition in the
current LS is word.
NOUN2 word
Succeeds if the second noun in the
current LS is word.
ADJECT2 word
Succeeds if the second noun's
adjective in the current LS is word.
The following condition is for
random occurrences. You could use it to provide a chance of a
tree
falling on the player during a
lightning strike or a bridge collapsing etc. Do not abuse this
facility,
always allow a player a way of
preventing a problem; such as rubber boots for the lightning, or
similar.
CHANCE percent
Succeeds if percent is less than or
equal to a random number in the range 1-100 (inclusive). This a
CHANCE 50 condition would allow PAW
to look at the next CondAct only if the random number
generated was between 1 and 50, a 50%
chance of success.
A single condition to test for a timeout;
TIMEOUT
Will succeed if the last request for
input from the player was allowed to timeout. For example an
entry
in Process table 2 of; TIMEOUT
MESSAGE 0 (where message 0 read "Come on sleepy") could
be
created, perhaps with a CHANCE or a
count of time outs to make it less monotonous!
The true CondAct;
QUIT
SM12 ("Are you sure") is
printed and the input routine called. Will succeed if the player
replies with
the first letter of SM30
("Y") to the prompt. If not then Actions NEWTEXT and
DONE are performed.
Actions
There are nineteen actions to deal with the manipulation of object positions;
GET objno.
If Object objno. is worn or carried,
SM25 ("I already have the _.") is printed and actions
NEWTEXT
DONE are performed.
If Object objno. is not at the
current location, SM26 ("There isn't one of those
here.") is printed and
actions NEWTEXT DONE are performed.
If the total weight of the objects
carried and worn by the player plus Object objno. would exceed
the
maximum conveyable weight (Flag 52)
then SM43 ("The _ weighs too much for me.") is printed
and
actions NEWTEXT DONE are performed.
If the maximum number of objects
is being carried (Flag 1 is greater than, or the same as, Flag
37) ("I
can't carry any more things.")
is printed and actions NEWTEXT DONE are performed. In addition
any
current DOALL loop is cancelled.
Otherwise the position of Object
objno. is changed to carried, Flag 1 is incremented and SM36
("I now
have the _.") is printed.
DROP objno.
If Object objno. is worn then SM24
("I can't. I'm wearing the _.") is printed and actions
NEWTEXT
DONE are performed.
If Object objno. is at the current
location (but neither worn nor carried), SM49 ("I don't have
the _.") is
printed and actions NEWTEXT DONE are
performed.
If Object objno. is not at the
current location then SM28 ("I don't have one of
those.") is printed and
actions NEWTEXT DONE are performed.
Otherwise the position of Object
objno. is changed to the current location, Flag 1 is decremented
and
SM39 ("I've dropped the
_.") is printed.
WEAR objno.
If Object objno. is at the current
location (but not carried or worn) SM49 ("I don't have the
_.") is
printed and actions NEWTEXT DONE are
performed.
If Object objno. is worn, SM29
("I'm already wearing the _.") is printed and action
NEWTEXT DONE
are performed.
If Object objno. is worn, SM29
("I'm already wearing the _.") is printed and actions
NEWTEXT DONE
are performed.
If Object objno. is not carried,
SM28 ("I don't have one of those.") is printed and
actions NEWTEXT
DONE are performed.
If Object objno. is not flagged as
Wearable (WR option in the object weight menu) then SM40 ("I
can't
wear the _.") is printed.
Otherwise the position of Object
objno. is changed to worn, Flag 1 is decremented and SM37
("I'm
now wearing the _.") is printed.
REMOVE objno
If Object objno. is carried or at the
current location (but not worn) then SM50 ("I'm not wearing
the
_.") is printed and actions
NEWTEXT DONE are performed.
If Object objno. is not worn, SM23
("I'm not wearing one of those.") is printed and
actions NEWTEXT
DONE are performed.
If Object objno. is not flagged as
wearable (and thus removable) then SM41 ("I can't remove the
_.") is
printed and actions NEWTEXT DONE are
performed.
If the maximum number of objects
is being carried (Flag 1 is greater than, or the same as, Flag
37),
SM42 ("I can't remove the _. My
hands are full.") is printed and actions NEWTEXT DONE are
performed.
Otherwise the position of Object
objno. is changed to carried. Flag 1 is incremented and SM38
("I've
removed the _.") printed.
CREATE objno
The position of Object objno. is
changed to the current location and Flag 1 is decremented if the
object
was carried.
DESTROY objno.
The position of Object objno. is
changed to not-created and Flag 1 is decremented if the object
was
carried.
SWAP objno1 objno2
The positions of the two objects are
exchanged. Flag 1 is not adjusted. The currently referenced
object
is set to be Object objno2.
PLACE objno. locno+
The position of Object objno. is
changed to Location locno. Flag 1 is decremented if the object
was
carried. It is incremented if the
object is placed at location 254 (carried).
PUTO locno+
The position of the currently
referenced object (i.e. that object whose number is in flag 51),
is changed
to be Location locno. Flag 54 remains
its old location. Flag 1 is decremented if the object was
carried.
It is incremented if the object is
placed at location 254 (carried).
PUTIN objno. locno.
If Object locno. does not exist or is
not flagged as a container (option C on the object weight menu)
then a run time error is generated of
"Illegal Argument".
If Object objno. is worn then SM24
("I can't. I'm wearing the _.") is printed and actions
NEWTEXT
DONE are performed.
If Object objno. is at the current
location (but neither worn nor carried), SM49 ("I don't have
the _.") is
printed and actions NEWTEXT DONE are
performed.
If Object objno. is not at the
current location, but not carried, then SM28 ("I don't have
one of those.")
is printed and actions NEWTEXT DONE
are performed.
Otherwise the position of Object
objno. is changed to Location locno. Flag 1 is decremented and
SM44
("The _ is in the"), a
description of Object locno. and SM51 (".") is printed.
TAKEOUT objno. locno.
If Object locno. does not exist or is
not flagged as a container (option C on the object weight menu)
then a run time error is generated
"Illegal Argument".
If Object objno. is worn or
carried, SM25 ("I already have the _.") is printed and
actions NEWTEXT
DONE are performed.
If Object objno. is at the current
location, SM45 ("The _ isn't in the"), a description of
Object locno.
and SM51 (".")is printed
and actions NEWTEXT DONE are performed.
If Object objno. is not at the
current location and not at Location locno. then SM52
("There isn't one of
those in the"), a description of
Object locno. and SM51 (".")is printed and actions
NEWTEXT DONE
are performed.
If Object locno. is not carried or
worn, and the total weight of the objects carried and worn by the
player
plus Object objno. would exceed the
maximum converyable weight (Flag 52) then SM43 ("The _
weighs too much for me.") is
printed and actions NEWTEXT DONE are performed.
If the maximum number of objects
is being carried (Flag 1 is greater than, or the same as, Flag
37),
SM27 ("I can't carry any more
things.") is printed and actions NEWTEXT DONE are performed.
In
addition any current DOALL loop is
cancelled.
Otherwise the position of Object
objno. is changed to carried, Flag 1 is incremented and SM36
("I now
have the _.") is printed.
Note: No check is made, by either
PUTIN or TAKEOUT, that Object locno. is actually present. This
must be carried out by you if
required.
DROPALL
All objects which are carried or worn
are created at the current location (i.e. all objects are dopped)
and
Flag 1 is set to 0. This is included
for compatibility with older writing systems. Note that DOALL 254
will carry out a true DROP ALL,
taking care of any special actions included.
The next six actions are automatic
versions of GET, DROP, WEAR, REMOVE, PUTIN and
TAKEOUT. They are automatic in that
instead of needing to specify the object number, they each
convert Noun (Adjective)1 into the
currently referenced object - by searching the object word table.
The
search is for an object which is at
one of several locations in descending order of priority - see
individual descriptions. This search
against priority allows PAW to 'know' which object is implied if
more than one object with the same
Noun description (when the player has not specified an adjective)
exists; at the current location,
carried or worn - and in the container in the case of TAKEOUT.
AUTOG
A search for the object number
represented by Noun (Adjective)1 is made in object word order of
location priority; here, carried,
worn. i.e. The player is more likely to be trying to GET an
object that is
at the current location than one that
is carried or worn. If an object is found its number is passed to
GET action. Otherwise if there is an
object in existence anywhere in the game if Noun1 was not in the
vocabulary then SM26 ("There
isn't one of those here.") is printed. Else SM8 ("I
can't do that.") is
printed (i.e. It is not a valid
object but does exist in the game). Either way actions NEWTEXT
DONE
are performed.
AUTOD
A search for the object number
represented by Noun (Adjective)1 is made in object word in order
of
location priority; carried, worn,
here. i.e. The player is more likely to be trying to DROP a
carried
object than one that is worn or here.
If an object is found its number is passed to the DROP action.
Otherwise if there is an object in
existence anywhere in the game or if Noun1 was not in the
vocabulary
then SM28 ("I don't have one of
those.") is printed. Else SM8 ("I can't do that.")
is printed (i.e. It is
not a valid object but does exist in
the game). Either way actions NEWTEXT DONE are performed.
AUTOW
A search for the object number
represented by Noun (Adjective)1 is made in object word in order
of
location priority; carried, worn,
here. i.e. The player is more likely to be trying to WEAR a
carried
object than one that is worn or here.
If an object is found its number is passed to WEAR action.
Otherwise if there is an object in
existence anywhere in the game or if Noun1 was not in the
vocabulary
then SM28 ("I don't have one of
those.") is printed. Else SM8 ("I can't do that.")
is printed (i.e. It is
not a valid object but does exist in
the game). Either way actions NEWTEXT DONE are performed.
AUTOR
A search for the object number
represented by Noun (Adjective)1 is made in object word in order
of
location priority; worn, carried,
here. i.e. The Player is more likely to be trying to REMOVE a
worn
object than one that is carried or
here. If an object is found its number is passed to the REMOVE
action. Otherwise if there is an
object in existence anywhere in the game or if Noun1 was not in
the
vocabulary then SM23 ("I can't
do that.") is printed (i.e. It is not a valid object but
does exist in the
game). Either way actions NEWTEXT
DONE are performed.
AUTOP locno.
A search for the object number
represented by Noun (Adjective)1 is made in object word in order
of
location priority; carried, worn,
here. i.e. The plyaer is more likely to be trying to PUT a
carried object
inside another than one that is worn
or here. If an object is found its number is passed to the PUTIN
action. Otherwise if there is an
object in existence anywhere in the game or if Noun1 was not in
the
vocabulary then SM28 ("I don't
have one of those.") is printed. Else SM8 ("I can't do
that.") is printed
(i.e. It is not a valid object but
does exist in the game). Either way actions NEWTEXT DONE are
performed.
AUTOT locno.
A search for the object number
represented by Noun (Adjective)1 is made in object word in order
of
location priority; in container,
carried, worn, here. i.e. The player is more likely to be trying
to get an
object out of a container which is
actually in there than one that is carried, worn or here. If an
object is
found its number is passed to the
TAKEOUT action. Otherwise if there is an object in existence
anywhere in the game or if Noun1 was
not in the vocabulary then SM52 ("There isn't one of those
in
the "), a description of Object
locno. and SM51 (".") is printed. Else SM8 ("I
can't do that.") is printed
(i.e. It is not a valid object but
does exist in the game). Either way actions NEWTEXT DONE are
performed.
Note: No check is made, by either
AUTOP or AUTOT, that Object locno. is actually present. This must
be carried out by you - if required.
COPYOO objno1 objno2
The position of Object objno2 is set
to be the same as the position of Object Objno1. The currently
referenced object is et to be Object
objno2.
There ae four actions which allow
various parameters of objects to be; placed in flags, set fro
flags - for
comparison or manipulation.
COPYOF objno. flagno.
The position of Object objno. is
copied into Flag flagno. This could be used to examine the
location of
an object in a comparison with
another flag value. e.g. COPYOF 1 11 SAME 11 38 could be used to
check that object 1 was at the same
location as the player - although ISAT 1 255 would be better!
COPYFO flagno. objno.
The position of Object objno. is set
to be the contents of Flag flagno. An attempt to copy from a flag
containing 255 will result in a run
time error of "Invalid Argument". Setting an object to
an invalid
location will still be accepted as it
presents no danger to the operation of PAW.
WHATO
A search for the object number
represented by Noun (Adjective)1 is made in object word in order
of
location priority; carried, worn,
here. This is because it is assumed any use of WHATO will be
related
to carried objects rather than any
that are worn or here. If an object is found its number is placed
in flag
51, along with the standard current
object parameters in flags 54-57. This allows you to create other
auto actions (the tutorial gives an
example of this for dropping objects in the tree).
WEIGH objno. flagno.
The true weight of Object objno. is
calculated (i.e. if it is a container, any objects inside have
their
weight added - don't forget that
nested containers stop adding their contents after ten levels)
and the
value is placed in Flag flagno. This
will have a maximum value of 255 which will not be exceeded. If
Object objno. is a container of zero
weight, Flag flagno. will be cleared as objects in zero weight
containers, also weigh zero!
Now ten actions to manipulate the flags;
SET flagno.
Flag flagno. is set to 255.
CLEAR flagno.
Flag flagno. is cleared to 0.
LET flagno. value
Flag flagno. is set to value.
PLUS flagno. value
Flag flagno. is increased by value.
If the result exceeds 255 the flag is set to 255.
MINUS flagno. value
Flag flano. is decreased by value. If
the result is negative the flag is set to 0.
ADD flagno1 flagno2
Flag flagno2 has the contents of Flag
flagno1 added to it. If the result exceeds 255 the flag is set to
255.
SUB flagno1 flagno2
Flag flagno2 has the contents of Flag
flagno1 subtracted from it. If the result is negative the flag is
set
to 0.
COPYFF flagno1 flagno2
The contents of Flag flagno1 is
copied to Flag flagno2.
RANDOM flagno.
Flag flagno. is set to a number from
the Pseudo-random sequence from 1 to 100. This could be useful
to allow random decisions to be made
in a more flexible way than with the CHANCE condition.
MOVE flagno
This is a very powerful action
designed to manipulate PSI's. It allows the current LS Verb to be
used to
scan connections table for the
location given in Flag flagno. If the Verb is found then Flag
flagno. is
changed to be the location number
associated with it, and the next condact is considered. If the
verb is
not found, or the original location
number was invalid, then PAW considers the next entry in the
table -
if present. This you could consider
that PAW carries out the following imaginary entries on exit from
Response if no action has been done;
_ _ MOVE 38 ; Attempt to move
player
DESC ; Describe this new loc.
_ _ LT 33 14 ; Movement word?
SYSMESS 7 ; "Can't go that
way.."
DONE
_ _ SYSMESS 8 ; "I can't do that"
This feature could be used to
provide characters with Random movement in valid directions; by
setting
the LS Verb to a random movement word
and allowing MOVE to decide if the character can go that
way. Note that any special movements
which are dealt with in the Response for the player, must be
dealt with separately for a PSI as
well.
Three actions to manipulate the flags dealing with the player;
GOTO locno.
Changes the current location to
locno. This effectively sets flag 38 to the value locno.
WEIGHT flagno.
Calculates the true weight of all
objects carried and worn by the player (i.e. any containers will
have the
weight of their contents added upto a
maximum of 255) this value is then placed in Flag flagno. This
would be useful to ensure the player
was not carrying too much weight to cross a bridge without it
collapsing etc.
ABILITY value1 value2
This sets Flag 37, the maximum number
of objects conveyable, to value1 and Flag 52, the maximum
weight of objects the player may
carry and wear at any one time (or their strength), to be value2.
No
checks are made to ensure that the
player is not already carrying more than the maximum. GET and so
on, which check the values, will
still work correctly and prevent the player carrying any more
objects,
even if you set the value lower than
that which is already carried!
There are seven actions which deal
with the manipulation of the flags for the screen mode, format
and
input etc;
MODE mode option
There are five screen modes each
controlled by Flag 40 and set using the MODE action thus:-
Mode 0
If a picture (other than
'subroutine') is present in the database, the screen is cleared
to the default
colours and the picture drawn. Once a
key is pressed the original colours are restored, and the
location
is described.
Mode 1
Text Only. Full screen scroll. Text
is output to the screen continuously. CLS is not active on
describe.
Mode 2.
If a picture (other than
'subroutine') is present in the database, the screen is cleared
to the default
colours and the picture drawn. The
original colours are restored, the area below the line given in
Flag
41 is cleared and text printed from
the same line.
Mode 3
As Mode 2 above but the picture does
not scroll away.
Mode 4
A text only mode which protects the
location description as if it were a picture, all other text
scrols
under. You will probably need a
PROTECT action at a suitable point in Process 1 (e.g. after
LISTOBJ?) as otherwise only as far as
the last but one line of text will be protected.
In all graphic modes above; option
2 forces the border NOT to be set to the Paper colour - it's best
to
select this in modes 2 & 3 as the
border is reset as soon as the picture is fully drawn causing an
annoying flicker. Option 1 makes SM32
("More.") appear when the screen area fils (unlike
"Scroll?"
you cannot breakout - will, in the
editor you can!). Option 3 of course provides both options and
option
0 neither! e.g. MODE 4 1 will select
a fixed text window with a "More." prompt.
LINE lineno.
This sets the line that text should
be printed from in the split screen graphic modes, and in the
case of
mode 2 the top line of the area to be
cleared. Be careful when using a lower screen input (see INPUT
action) to allow at least four spare
lines in the upper screen (not forgetting to account for the
number of
lines used by the prompt and marker)
or a runtime error will occur if a full input line is entered.
GRAPHIC option
This allows the way in which pictures
are dealt with by PAW to be modified, there are three valid
options;
0 - Normal, any picture present
for a location is drawn when the player first visits that
location, and then
only if pictures are turned ON or a
temporary redraw is requested.
1 - OFF, any pictures are completely ignored by PAW, even if a temporary redraw is requested.
2 - ON, any picture present for a location is drawn every time the player visits that location.
There is an option 3 (option =
2+1) but pictures OFF takes priority anyway, so it is redundant.
The
current picture for a location can be
redrawn by adding 128 to flag 29, this is a temporary redraw,
which
can be used for when the player
requests the picture in Normal mode. i.e. PLUS 29 128 DESC would
be required entry in Response.
PROMPT sysno.
Causes System message sysno. to be
displayed whenever PAW obtains a command line from the player.
A value of 0 (default) will cause PAW
to select one of SM2, SM3, SM4 or SM5 in the ratio
30:30:30:10 respectively. Note this
does not affect the prompts displayed by the END or QUIT
condacts.
TIME duration option
Allows input to be set to 'time-out'
after a specific duration in 1.28 secon intervals, i.e. the
Process 2
table will be called again if the
player types nothing for the specified period. 'option' allows
this to
also occur on ANYKEY and
"More." prompt. In order to calculate the number to use
for the option
just add the numbers hown next to
each item to achieve the required combination;
1 - While waiting for the first
character of Input only.
2 - While waiting for the key on the
"More." prompt.
4 - While waiting for the key on the
ANYKEY action.
e.g. TIME 5 6 (option = 2+4) will
allow 6.4 seconds of inactivity on behalf of the player on input,
ANYKEY or "More." and
between each keypress. Whereas TIME 5 3 (option = 1+2) allows it
only
on the first character of input and
on "More.".
Time 0 0 will stop timeouts (default).
INPUT options
This action allows the way the input
routine operates to be changed by selecting options. Some
combinations are of no use but are a
by product of the way PAW works. To calculate the number to use
for the option just add the numbers
shown next to each item to achieve the required combination;
1 - Will cause the input prompt,
marker and cursor to be displayed in the lower screen area. This
is the
preferred input mode for time out
games, where timeout can occur between keypresses, as the input
line
is not left partially printed if
timeout occurs part way through.
2 - will cause PAW to print a copy
of the input line when ENTER is pressed, this is for use mainly
with
item 1 to allow the final input line
to be displayed on screen so that the player knows what has been
typed.
4 - This will cause the reprint of
any text input so far, when input is resumed after a timeout.
Again
mainly for use with item 1 when
timeout can occur between keypresses.
A default of INPUT 0 (no options) is assumed by PAW.
PROTECT
Used in conjunction with MODE 4
mainly. This action sets the current print line as the top of the
scrolling text window. It should only
be used within Process 1 (it will be allowed elsewhere but has no
meaning) after any text you want
protected has been printed. This is usually before / after a
LISTOBJ
action as objects are usually the
last thing printed.
It also has uses in other modes to
allow say a picture and part of the location description to be
protected, with the remainder of the
text scrolling underneath!
Three actions to deal with the printing of flag values on the screen;
PRINT flagno.
The decimal contents of Flag flagno.
are displayed in the current temporary colours without leading or
trailing spaces. This is a very
useful action. Say flag 100 contained the number of coins carried
by the
player, then an entry in a process
table of MES 10 ("You have ") PRINT 100 MESSAGE 11
(" gold
coins."), could be used to
display this to the player.
TURNS
SM17-20 "You have taken x
turn(s)." is printed where x is Flag 31 + 256 * Flag 32.
SCORE
SM21-22 "You have scored
x%" is printed where x is Flag 30.
Thirteen (!) actions to deal with screen output and control;
CLS
Clears the screen to current
background colours. Also clears the current print position and
SAVEAT
position to 0,0.
NEWLINE
Prints spaces to the end of the
current line and then resets the colours & character set to
the current
background colours.
MES msno.
Prints Message mesno. in the current
temporary colours, then carries out a NEWLINE action.
SYSMESS sysno.
Prints System Message sysno. in the
current temporary colours.
PICTURE locno.
Draws graphics picture locno.
regardless of whether it is a subroutine or main picture. Note:
the screen
and colours are not cleared first as
with describe location. This could be used to add (or take away
if
you PRINTAT and MES to remove with
spaces) parts of a picture. The sample game TEWK uses this
feature several times. Note that a
picture will be drawn from the last point used by the previous
picture
drawn!
PAPER n
Where n ranges from 0 to 9. Changes
background paper colour.
INK n
Where n ranges from 0 to 9. Changes
background ink colour.
BORDER n
Where n ranges from 0 to 7. Changes
screen border colour.
CHARSET value
Changes main character set to value
given if valid, otherwise no action is taken.
The next three screen control
actions allow a section of text to be printed on the screen away
from the
current print position. This could be
used to provide an information line on top of the current
picture,
or a section of text in a small
window on the picture etc etc. TEWK uses this facility to provide
its drop
down window inventory in response to
the STATUS command.
SAVEAT
Flushes the current wordwrap buffer
thus restoring the current background colours. Then saves the
current print position, overwriting
any previously saved position.
BACKAT
Flushes the current wordwrap buffer
thus restoring the current background colours. Then restores the
print position last saved by SAVEAT.
PRINTAT lineno. colno.
The current print position is changed
to the specified value. note this will also flush the wordwrap
buffer and restore the temporary
colours to the background colours.
Three actions dealing with listing
objects on the screen. The first two are controlled by / set the
value
of Flag 53 as desribed in the chapter
on objects.
LISTOBJ
If any objects are present then SM1
("I can also see:") is printed, followed by a list of
all objects present
at the current location. If there are
no objects then nothing (as in null, not the word!) is printed.
LISTAT locno+
If any objects are present then they
are listed. Otherwise SM53 ("nothing.") is printed -
note that you
will usually have to precede this
action with a message along the lines of "In the bag
is;" etc. It would
be possible to create an alternative
to the INVEN action described next by using 254 & 254 as
parameters for LISTAT.
INVEN
This action is not affected by the
continuous object list flag for compatibility with older writing
systems.
SM9 ("I have with me:")
is printed. If no objects are carried or worn SM11 ("Nothing
at all.") is
printed. Otherwise the object text
for each object that is carried or worn is printed on a separate
line. If
an object is worn its object text is
followed by SM10 (" (worn)"), right aligned on the next
line if it will
not fit on the same one. Action DONE
is then performed.
The two actions which completely exit Response / Process execution;
DESC
Will cancel any DOALL loop, any
sub-process calls and make a jump to describe the current
location.
END
SM13 ("Would you like to play
again?") is printed and the input routine called. Any DOALL
loop an
sub-process calls are concelled. If
the reply does not start with the first character of SM31 a jump
is
made to Initialise. Otherwise a jump
is made to the Editor (if it is present) or to the BASIC NEW
command.
Three exit table actions;
DONE
This action jumps to the end of the
process table and flags to PAW that an action has been carried
out.
i.e. no more condacts or entries are
considered. A return will this be made to the previous calling
process table, or to the start point
of any active DOALL loop.
NOTDONE
This action jumps to the end of the
process table and flags to PAW that no action has been carried
out.
i.e. no more condacts or entries are
considered. A return will this be made to the previous calling
process table or to the start point
of any active DOALL loop. This will cause PAW to print one of the
"I can't" messages if
needed. i.e. if no other action is carried out and no entry is
present in connections
for the current Verb.
OK
SM15 ("OK") is printed and
action DONE is performed.
Four actions to allow the current state of the game to be saved and restored;
SAVE
The standard start tape message for
the spectrum is printed at the bottom of the screen. When a key
is
pressed the game position is saved to
tape, then action DESC is performed. If BREAK is pressed
during the save a jump is made to
Initialise. The save includes all information required to allow
the
restoration of the game to the exact
same as it was before the save, including the values of flags,
positions of objects, picture drawn
flags etc.
LOAD
Loads data (which should be a game
position) from tape, then action DESC is performed. If BREAK is
pressed during the load or a tape
error is detected a jump is made to Initialise. If data is loaded
which is
not a game position, a tape error
will normally be detected.
RAMSAVE
In a similar way to SAVE this action
saves all the information relevant to the game in progress not
onto
tape but into a memory buffer. This
buffer is of course volatile and will be destroyed when the
machine
is turned off which should be made
clear to the player. In addition it will also be cleared when you
return to the editor section of PAW -
in case you then change the design of the game!
RAMLOAD flagno.
This action is the counterpart of
RAMSAVE and allows the saved buffer to be restored. The parameter
specifies the last flag to be
reloaded which can be used to preserve values over a restore, for
example an
entry of:
RAMLO _ COPYFF 30 255
RAMLOAD 254
COPYFF 255 30
DESC
could be used to maintain the
current score, so that the player can not use RAMSAVE / LOAD as
an
easy option for achieving 100%.
Note: unlike SAVE and LOAD the RAM
actions allow the next Condact to be carried out. They
should normally always be followed by
a DESC in order that the game state is restored to an identical
position.
The actions could be used to
implement an OOPS command that is common on other systems to take
back the previous move; by creating
an entry in Process 2 (or Response) which does an automatic
RAMSAVE every time the player enters
a move.
Two actions to allow the game to be paused to a time or until a key is pressed;
ANYKEY
SM16 ("Press any key to
continue") is printed at the bottom of the screen and the
keyboard is scanned
until a key is pressed or until the
timeout duration has elapsed if enabled.
PAUSE value
Pauses for value / 50 secs. However,
if value is zero then the pause is for 256/50 secs. Note that the
keyboard is disabled for the duration
of the pause.
Two actions to deal with control of the parser;
PARSE
This action was designed to deal with
speech to PSIs. Any string (i.e. a further phrase enclosed in
quotes [" "]) that was
present in the players current phrase is converted into a LS -
overwriting the
existing LS formed originally for
that phrase. If no phrase is present or it is invalid, then PAWW
will
look at the next condact. Otherwise
the next entry is considered with the new LS of the speech made
to
the PSI. Because it overwrites the
current LS it must be used only in a sub-response table, the
table will
have form of:
* * PARSE ; Always do this entry
MESSAGE x ; "They don't
understand"
DONE
word word CondAct list ; Any phrase PSI understands
_ _ MESSAGE x ; as above or different message
there will be two or more calling entries which will be similar to:
SAY name SAME pos 38 ; Are they
here?
PROCESS y ; Decode speech..
DONE ; LS destroyed so always DONE.
SAY name MESSAGE x ; "They
are not here!"
DONE
NEWTEXT
Forces the loss of any remaining
phrases on the current input line. You would use this to prevent
the
player continuing without a fresh
input should something go badly for his situation. e.g. the GET
action
carries out a NEWTEXT if it fails to
get the required object for any reason, to prevent disaster with
a
sentence such as:
GET SWORD AND KILL ORC WITH IT
as attacking the ORC without the sword may be dangerous!
One action to deal with sound
BEEP duration pitch
Both duration and pitch may range
from 0 to 255. Duration is in units of one hundredth of a second.
The value of itch is obtained by
taking the value you would use in a BASIC BEEP command, adding 60
then dividing by 2.
Several actions which are more difficult to classify;
PROCESS procno.
This powerful action transfers the
attention of PAW to the specified Process table number. This sub-
process will exhibit the same
features as the table which called it. i.e. if called by
Response, PAW will
match the Verb and Noun1 of the LS
against the word entries as with the main table. Note that it is
a
true subroutine call and any exit
from the new table (e.g. DONE, OK etc) will return control to the
condact which follows the calling
PROCESS action. A sub-process can call (nest) further process' to
a
depth of 10 at which point a run time
error of "Limit reached" will be generated.
DOALL locno+
Another powerful action allows the
implementation of an 'ALL' type command.
1 - An attempt is made to find an
object at Location locno. If this is unsuccessful the DOALL is
cancelled and action DONE is
performed.
2 - The object number is converted
into the LS Nound1 (and Adjective1 if present) by reference to
the
object word table. If Noun
(Adjective)1 matches Noun (Adjective)2 then a return is made to
step 1.
This implements the "Verb ALL
EXCEPT object" facility of the parser.
3 - The next condact and / or
entry in the table is then considered. This effectively converts
a phrase of
"Verb All" into "Verb
object" which is then processed by the table as if the
player had typed it in.
4 - When an attempt is made to
exit the current table, if the DOALL is still active (i.e. has
not been
cancelled by an action) then the
attention of PAW is returned to the DOALL as from step 1; with
the
object search continuing from the
next highest object number to that just considered.
The main ramification of the
search method through the object word table is; objects which
have the
Same Noun (Adjective) description
(where the game works out which object is referred to by its
presence) must be checked for in
ascending order of object number, or one of them may be missed.
Use of DOALL to implement things
like OPEN ALL must account for the fact that doors are often
flags
only and would have to be made into
objects if they were to be included in a DOALL.
RESET locno+
This action is designed to allow the
implementation of multi-part games where the objects which are
not
carried forward are reset to their
starting location.
All objects which can be carried
between parts must be present (with the same description) in each
part.
Any others may be reused within each
part at will.
Any objects which are present at
the current location are moved to Location locno. And the current
location is set to be locno. Any
other objects are set to the locations given by the Initially At
table. No
effect on flags. Action DESC is
performed when complete.
The suggested method of its use is given in the chapter on multi-part games.
EXTERN value
Calls external routine with parameter
value. There is a special chapter dealing with this subject.
Detailed Description of the
Database
The database consists of a number of
inter-related tables and also contains an area of miscellaneous
information e.g. values of background
colours, number of objects conveyable, character sets etc. On a
128K machine the main data areas and
pointers are present for each RAM page. Effectively each page
is an independent database. The
tables present (in the order they appear in memory) are:
UDG's
This table, which is 152 bytes long,
contains the User Defined Graphics. The UDG's can be changed
with the character editor described
later. Codes 144-162.
Shades
This table is 128 bytes long and
contains the graphics Shade patterns. These can be changed with
the
character editor as described later.
Codes 0-15.
The above two tables are saved /
loaded as a pair and are termed character set 0. (although the
ROM set
provides codes 32-127).
Miscellaneous
Several small tables and values, 50
bytes in total.
Character Sets
This table is empty until a character
set is inserted using the character editor. 768 bytes are used
then
by each character set inserted.
Dictionary
This table contains only one byte
until the compressor is used for the first time on the database.
After
that it contains 222 bytes of
expansion dictionary to allow the tokens 165-255 to be converted
into the
letter groupings they represent.
The Process tables
These tables form the heart of the
database providing the main game control.
The Response Table
Each entry contains the word values
of the Verb and Noun for the LS the entry is to deal with
followed
by any number of condacts. When the
adventure is played, if there is an entry in the table which
matches the Verb and Noun1 of the LS
entered then the condacts are performed. The condacts that may
be present and the effect that they
have is fully specified in the description of the Interpreter.
The order
of entries in the table is in
ascending order of the Verb value. Entries which have the same
Verb value
are held in ascending order of the
Noun value. Entries with the same Verb and Noun value are held in
the order they were inserted into the
database. The word "_" has a word of value 255 while
the word
"*" has a word value of 1.
An example of the order of the table, with word value shown in
brackets, is
as follows:
* (1) * (1)
LOOK (30) UP (10)
LOOK (30) DOWN (11)
LOOK (30) _ (255)
GET (100) * (1)
GET (100) KEY (16)
GET (100) LAMP (26)
GET (100) LAMP (26)
_ (255) _ 255
The other process tables are held
in the same format, but the words are ignored by PAW when they
are
scanned, unless the process is called
from within Response using a PROCESS action.
Process 1
Is canned by PAW after a location is
described, to allow any additional information which forms a part
of the location description to be
displayed.
Process 2
Is scanned by PAW after every time
frame. That is after every phrase extracted from the player's
input,
or after every time-out on input.
Any further sub-processes follow the initial three when begun on the Process option of the main menu.
The Verb and Noun used for each
entry in Process 1 and 2 (and any sub-processes called from them)
have no meaning as they are ignored
but can be used to provide a note as to the function of that
entry
within the table.
Every process table has an
overhead of seven bytes (21 are used in a null database as three
- including
Response - are already present.) Each
entry subsequently uses 5 bytes and each condact uses 1, 2 or 3
bytes depending on the number of
parameters.
Note: If a word is deleted from
the vocabulary, and no synonyms of it are present, then all
entries in the
process tables (including Response)
which contain that word, are also deleted.
The Object Text table
This table, which has an entry for
each object, contains the text which is printed when an object is
described. Each entry uses 3 bytes
plus the length of the text. An object is anything in the
adventure
which may be manipulated and objects
are numbered from 0 upwards. Object 0 is assumed by the
Interpreter to be a source of light.
Whenever a new object text is inserted an entry of not-created is
made for that object in the Initially
at table, an entry of "_ _" in object word and a weight
of 1 unit
without a container or wear / remove
attribute is inserted into the object weight table.
The Location Text table
This table, which has an entry for
each location, contains the text which is printed when a location
is
described. Each entry uses 3 bytes
plus the length of the text. The entries are numbered from 0
upwards and location 0 is the
location at which the adventure starts. Whenever a new location
is
inserted a null entry for that
location is also made in the connections table.
The Message Text table
This table contains the text of any
messages which are needed for the adventure. The messages are
numbered form 0 upwards and each one
uses 3 bytes plus the length of the text.
The System Messages
This table contains the messages used
by the Interpreter. Each entry uses 3 bytes plus the length of
the
text. The description of the
Interpreter shows when these messages are used. In addition extra
messages can be inserted by the
writer to provide messages for the game if so required.
The Connections table
This table has an entry for each
location and each entry may either be empty (null) or contain a
number
of 'movement pairs'. A movement pair
consists of a word value of a Verb (or conversion Noun) from
the vocabulary followed by a location
number. This means that any Verb (or conversion Noun) with
that word value causes movement to
that location. A typical entry could be SOUTH 6 EAST 7 LEAVE
6 NORTH 5 which means that SOUTH or
LEAVE or their synonyms cause movement to location 6,
EAST or its synonyms to location 7
and NORTH or its synonyms to location 5. Each entry uses 3 bytes
plus 2 bytes for each movement pair.
Note 1. The movement pairs contain
the word value not the actual word. If a word value is deleted
from
the vocabulary then all movement
pairs which contain that word value are also deleted.
Note 2. When the adventure is being played it is only the LS Verb which will cause movement.
Note 3. If a movement is performed
by an entry in the Response table using the GOTO action, then it
may not be needed in the Connections
table, unless that entry is required for a PSI who can move
unconditionally.
The Vocabulary
Each entry in the table uses 7 bytes
and contains a word (or the first five characters, if the word is
longer than five characters) a word
type from 0 to 6 and a word value in the range 2-254. The types
are:
0 - Verb
1 - Adverb
2 - Noun
3 - Adjective
4 - Preposition
5 - Conjugation
6 - Pronoun
Words with the same word value are
called synonyms. The entries are held in ascending order of word
value and within each word value,
entries with more spaces come first e.g.
U
UP
CLIMB
ASCEN(D)
where entries with the same word
value also have the same number of spaces the entry inserted
first
comes earlier e.g. CLIMB was inserted
before ASCEN(D).
Note 1. Whenever the editor has to
convert from a word value to a word it takes the first word with
that
value of the required type.
Note 2. Verbs and Conversion Nouns with values less than 14 should be reserved for movement words.
The Object Initially At table
This table has a 1 byte entry for
each object, which specifies the location at which the object is
situated
at the beginning of the adventure. An
object can also start the adventure being worn, carried or not-
created.
The Object Word table
This table has a 2 byte entry for
each object, which holds the Noun and Adjective word values
associated with that object.
The Object Weight and Attribute
table
This table has a one byte entry for
each word. Bit 7 is used to show if the object can be Worn /
Removed (i.e. the WR option). Bit 6
is used to show that the object is a container (the C option) and
Bits 0 to 5 define the weight of the
object (giving a range from 0-63).
The graphics area of the database grows DOWN from the top of memory:
The Location Flags
This table has a 1 byte entry for
each picture; Bit 7 specifies if the picture can be drawn when
that
location is reached (i.e. if the
location is not a 'subroutine'), bits 0 to 5 describe the start
PAPER &
INK for the picture while bite 6 is
unused.
The Picture Table
Each entry in the table uses 3 bytes
plus the length of the Drawstring. There are always the same
number of entries as locations in the
adventure. The Drawstring is encoded as a variety of various
length commands which minimise the
amount of memory needed to produce the drawing.
The Pointers
The main database pointers.
Detailed Description of the Editor
Each menu option is described in the
order it appears;
Vocabulary
Insert I word No. Type
No. is in the range 2-254 and Type is in the range 0-6.
If word is not already present in
the vocabulary it is inserted with a word value of No. and a type
of
Type.
Delete D word
If word is present in the vocabulary,
it, its type and its word value are deleted. If synonyms of the
word
deleted are present in the vocabulary
no further action is taken. However, if no synonyms are present,
then:
a) all entries in the process
tables which use this word value (in respect of type also) are
also deleted.
b) b) if the word value is less than
14 then all movements in the connection table which use this word
value are also deleted.
c) c) all entries in the Object Word
Table which use this word value (in respect of type also) are set
to
null.
Show synonyms S word
If word is present in the vocabulary,
it and all other words with the same word value and type are
displayed. (Note that for Conversion
Nouns - those less than 20 - any synonymous Verbs will also be
shown and vice-versa).
Print P (Type) or L (Type)
Printing is either to the screen
using P or to the printer using L. If Type is specified only
words of that
type are listed.
Note 1. Be careful using delete as
it can also affect the process, connections and object word
tables. It
can also take a long time (minutes)
if the database is large.
Note 2. Verbs and Nouns with a
word value of less than 14 are assumed to be movement words by
the
Interpreter and cause SM7 (I can't go
in that direction.") to be printed instead of SM8 ("I
can't do
that").
Note 3. Word values from 2 to 254
can be used for each word type. The words will not be synonymous
because they are of a different type.
This allows over 250 words of each type - even without synonums -
to exist in the vocabulary!
Location Text
Insert I
If the maximum number of locations
has been inserted then the error "Limit Reached" is
generated.
Otherwise the next available location
number on the highest used RAM page (shown on the Free
Memory option) is allocated and a
null entry is made for it in the graphic location text table.
Processing
then continues with an automatic call
to the amend routine to allow the writer to amend the null text
entry already set up in the location
text table.
Begin new Page B
If all RAM pages have been used or
the maximum number of locations have been inserted the error
"Limit Reached" is
generated. Otherwise the next available RAM page has a null
database created on it
an the next available location number
is assigned. Processing then continues with an automatic call to
the amend routine to allow the writer
to amend the null text entry in the new page.
Amend A locno.
The existing text for Location locno.
is copied to the input buffer and displayed at the bottom of the
screen for amending. When ENTER is
pressed the existing entry is replaced with the contents of the
input buffer.
Print P (locno.) or L (locno.)
Printing is either to the screen
using P or to the printer using L. Printing starts with the text
for
Location locno. or at the beginning
if locno. is not specified.
Note 1. The start of an adventure
is always at Location 0.
Note 2. There is a limit of 252
locations.
Note 3. You will be unable to begin a
new page if all available location numbers have been previously
allocated.
Connections
Amend A locno.
The existing entry for Location
locno. is decoded, copied to the input buffer and displayed at
the
bottom of the screen for amending.
When ENTER is pressed the input buffer is vetted to be empty or
to
contain word locno. repeated any
number of times. word must be a Verb (or Conversion Noun) which
is present in the vocabulary and
locno must be present in the location text table.
If there are no syntax errors the
existing entry is replaced with an encoded copy of the input
buffer (i.e.
words changed to word values).
Print P (locno.) or L locno.
Printing is either to the screen
using P or to the printer using L. Printing starts with the entry
for
Location locno. or at the beginning
if locno. is not specified.
Note 1. A location text must be
present for a Location before connections can be present.
Note 2. Any Verbs (or conversion
Nouns) in the Vocabulary may be used in the Connections table not
only movement words.
Note 3. When an entry is decoded (for
Amend or Print) the word value is changed into the first Verb
(or conversion Noun) in the
Vocabulary with that word value.
Graphics
Amend A picno.
The graphic database is expanded to
provide a gap at the end of the reruired picture. The main loop
of
the Graphics Editor described below
is then entered. When return is pressed any gap still remaining
is
removed. n.b. unlike editing text the
database itself is changed, this you cannot abandon an edit with
CAPS SHIFT & 6 (it does a NEXT
command for a start!).
Size S
The number of bytes between the start
of the drawstring and the start of the next is calculated and
printed on the screen.
Print, Copy and Dump. P picno., C
picno. and D picno.
picno. must be specified.
If D was selected a filename is requested.
The required picture is drawn on the screen.
If C was selected the printer COPY is called (see printer section for details).
If D was selected a SCREEN$ file
is saved with the filename given (i.e. a code block of the screen
16384,6912), this file could then be
used as a loading screen for the game or edited using another art
package.
Note 1. You cannot reload a SCREEN$ file into the database.
Default Colours
Amend A picno (Paper Ink)
A flag is set to indicate that
picture picno. is a subroutine unless PAPER and INK valued are
specified,
in which case they are stored as the
default colours for the picture. All locations in the adventure
which
do not require a picture should be
Amended as a subroutine.
Print P or L
Printing is either to the screen
using P or the printer using L. If the location is not a
subroutine the
colours are printed.
Messages
Insert I
The next available message number is
allocated and a null entry is made for it in the mesage text
table
on the highest used RAM page (shown
on the Free Memory option). An automatic call to the amend
routine is then made to allow the
user to amend the null entry.
Begin new Page B
The next available message number is
allocated to the null message on the next RAM page if it has ben
initialised on the location text
menu. Otherwise the error "Page not initialised" is
generated.
Processing countinues with an
automatic call to the amend routine to allow the user to amend
the null
entry.
Amend A mesno.
The existing text for message mesno.
is copied to the input buffer and displayed at the bottom of the
screen for amending. When ENTER is
pressed the existing text is replaced with the contents of the
input buffer.
Print P (mesno.) or L (mesno.)
Printing is either to the screen
using P or to the printer using L. Printing starts with the text
for
message mesno. or at the beginning if
mesno. is not specified.
Note 1. There is a limit of 255
messages, but as system messages can be inserted and printed they
can
also be used in the game providing
510 messages (although some are used!)
Note 2. You cannot begin a new page
of messages without first initialising the page by inserting a
location on it.
System Messages
Insert
The next available system message
number is allocated and a null entry made for it in the system
messaeg table on RAM page 0. An
automatic call is then made to the amnd routine to allow the
writer
to amend the null entry.
Amend A mesno.
The existing text for system message
mesno. is copied to the input buffer and displayed at the bottom
of
the screen for amending. When ENTER
is pressed, the existing text is replaced with the contents of
the
input buffer.
Print P (mesno.) or L (mesno.)
Print is either to the screen using P
or to the printer using L. Printing starts with the text for
system
message mesno. or at the beginning if
mesno. is not specified.
Note 1. The description of the
Interpreter shows where these messages are used. They may be
changed
to use "You" instead of
"I" if you prefer, i.e. "You're not wearing
it", or even into different languages,
but be careful to maintain their
meaning.
Note 2. Messages 30 and 31 are not
really messages but contain the positive and negative replies
used
in the QUIT and END condacts.
Therefore be very careful changing these as action END is the
main
way back to the Editor from the
Interpreter. You shoudn't make them more than one character in
length, or the compressor may
tokenise them!
Note 3. SM10 (" (worn")
has its length calculated by INVEN. This means it should not
include any
control codes, and must be re-entered
if the compressor is used to remove any tokens. In addition, for
the calculation of screen position to
work, it should start with a space.
Note 4. SM34 (the cursor) may
contain any number of control characters, but, must not move the
print
position more than one character
space or input will become confused. Any input character will be
in
the temporary colours in force at the
end of this message.
Note 5. A further 202 messages may
be inserted for your own use, but as there is no equivalent of
the
MESSAGE action a NEWLINE action must
be carried out explicitly if needed.
Note 6. CPM PAW uses messages 54
to 60. This should be borne in mind if you intend transferring a
game to another system.
Object Text
Insert I
The next available object number is
allocated and a null entry is made for it in the object text
atble. An
entry of not-created is made for it
in the object initially at table, an entry of "_ _" in
the object word
table and a weight of 1 unit without
any attributes in the object weight table. Processing then
continues
with an automatic call to the amend
routine to allow the user to amend the null text entry already
set up
in the object text table.
Amend A objno.
The existing text for Object objno.
is copied to the input buffer and displayed at the bottom of the
screen for amending. When ENTER is
pressed the existing text is replaced with the contents of the
input buffer.
Print P (objno.) or L (objno.)
Printing is either to the screen
using P or to the printer using L. Printing starts with the text
for Object
objno. or at the beginning if objno.
is not specified.
note 1. Object 0 is considered by the Interpreter to be a source of light.
Note 2. There is a limit of 255 objects.
Object Initially At table
Specifies the location at which an
object is situated at the start of the adventure.
Amend A objno. locno.
The existing entry for Object objno.
is replaced with locno. which must either be present in the
location
text table or be one of the special
locnos. 252 not-created, 253 worn or 254 carried.
Print P or L
Printing is to the screen using P or
to the printer using L.
Note 1. An object text must be present for an object before a start location can be present.
The Object Word table
Amend A objno. Noun Adjective
The existing entry for Object objno.
is replaced with the values of Noun and Adjective which must be
present in the Vocabulary (or be an
underline to set the entry to null).
Print P or L
Printing is to the screen using P or
to the printer using L.
The Object Weight table
Amend A objno. Weight Option
The existing entry of Object objno,
is replaced with the weight and option specified. The weight may
range from 0 to 64. The option
specifies the object attributes and may take the values:
0 - No attributes
1 - The object is a container.
2 - The object is wearable /
removable
3 - The object is a wearable /
removable container!
Print P or L
Printing is to the screen using P or
to the printer using L. The weight can be followed by
"C" to
indicate a container an / or
"WR" to indicate wearable / removable.
Note 1. You may only select the
container attribute for an object, if a location with the same
number
exists. This is because PAW trets
this location as the "inside"!
Note 2. A container of weight 0
will not have the weight of its contents added to any
calculation. This
could be used to create a magic sack
or a levitation transporter etc.
The Process (including Response)
tables
Two options are available only on the
main Process sub-menu:
Begin new Table B
The next available process number is
allocated and null table is created. Processing continues with a
call to the Select table option with
the new table number.
Select table S No.
The specified table is made the
currently selected table and the sub-menu is redisplayed.
The other options are available on both the Response and Process sub-menus:
Amend A Verb Noun (n)
If an entry number n is not specified
the first entry in the table of Verb and Noun is copied to the
input
buffer and displayed at the bottom of
the screen for amending. Otherwise the entry number specified is
used (ranging from 0 to the number of
entries inserted - 1). When ENTER is pressed the input buffer is
vetted to be empty, in which case the
existing entry is deleted, or to contain any number of valid
condacts. If there are no syntax
errors the existing entry is replaced with the contents of the
input
buffer. Any following entries in the
table with the same word values (i.e. Verb and Noun) are then
displayed in turn for amending in the
same way.
Insert I Verb Noun (n)
Verb and Noun must be underline
characters, asterisk characters or words which are in the
vocabulary.
The word values of Verb and Noun
(underline has a word value of 255, asterisk a word value of 1)
are
used to find the correct place in the
table for the new entry to be created. If any entries already
exist for
Verb Noun and no entry number n is
specified then the new entry will be created after the existing
entries. Otherwise the new entry will
be created before the entry number specified. A null entry is
created at the appropriate place and
an automatic call made to the amend routine to allow the user to
amend the null entry.
The condacts that may be used are
shown in the description of the Interpreter and in the summary at
the
end of this guide.
Print P (Verb (Noun)) or L (Verb
(Noun))
Printing is either to the screen
using P or to the printer using L. Printing starts at the first
entry with
word values of Verb Noun. If Verb or
Noun are not specified then a word value of 0 is assumed. This
P or L by itself starts at the
beginning of the table.
Note 1. To delete an entry; amend it, so that no conditions or actions remain.
Note 2. There is a limit of 255
process tables. Calls can be nested to maximum of 10, after which
an
error occurs.
Extra Options
Selects the other display for the
main menu.
Test Adventure
"Do you require
disgnistics?" is printed and any reply that doesn't start
with "Y" is assumed to be
negative. A jump is then made to the
Interpreter. If diagnostics were requested then whenever the
Interpreter's input routine is used,
pressing ENTER without typing anything will result in the value
of a
flag being displayed in the lower
screen along with an input prompt. You can at this point type in
the
number of another flag to display
that flag's value or an "=" folowed by a number to set
the flag
displayed to that value. Pressing
ENTER returns to the input.
The main way back to the Editor
from the Interpreter is by performing the action END in a process
table.
Free Memory
The number of unused bytes on each
page are printed. Pages which have not yet been initialised are
shown as "unused" and if
Page 7 currently contains the overlays this fact is also
displayed. Following
the unused memory list will be lists
of the last message and last location used on each page to allow
you
to monitor them.
Note that on a 48K spectrum only page 0 will be displayed - as that's all there is!
Background Colours
The BORDER, PAPER & INK colours
may be set to any valid values. INK 9 (i.e. contrast) is
recommended but please note that INK
9 behaves differently in the bottom part of the screen.
In addition if any character sets
have been inserted into the database you will be able to select
them as
the primary set.
Characters
Characters consist of an 8 by 8 pixel
grid and define the way letters, numbers, punctuation, UDG's and
shades look on the screen. Initially
only one character set is present, the one that is contained
within
the spectrum ROM. This set is also
considered to contain the 16 shade patterns (codes 0 to 15) and
19
UDG's (codes 144 to 162) and is
termed Set 0.
Insert I
If the maximum number of character
sets has not been reached the next available set number is
allocated. A 768 byte entry is
inserted in the character table and a copy of the designs for 96
characters
(codes 32 to 127) in the ROM are
copied into the entry. Otherwise an error of "Limit
Reached" is
generated.
Amed A set character
The character specified from the set
specified is presented on screen for possible amending. Only
characters 0 to 15 and 144 to 162 may
be amended from set 0, whereas only characters 32 to 127 may be
amended from any other set.
The editor provides three areas of screen:
1/ The Grid
The bit patterns of a particular
character are shown on a much enlarged (x8) grid of yellow and
white
squares, any set bits being shown by
a black square. Also present on the grid is a flashing red square
showing the current cursor position.
2/ The Test Patterns
To the right of the Grid are two test
patterns of the current character as if it was a shade in both
normal
& Inverted forms. This does not
change as you change the Grid but it can be updated by pressing R
for
Redraw.
3/ Status Area
This shows the current character, set
and a summary of the commands available.
In order to modify the pattern use
the cursor keys (CAPS SHIFT 5 to 8 on a 48K spectrum) to move the
flashing cursor. The state of the bit
under the cursor can be changed at any time using the SPACE key.
ENTER will store the amended
character back in the database. Q will abandon the edit leaving
the
character unchanged.
Print and Copy sets P or C
The currently defined UDG's, Shades
and inserted character sets are printed on the screen.
If C was selected then the printer COPY is called - see printer section for details.
Load and Save sets L set or S set
If set has been inserted a prompt
is printed for a filename, the tenth letter is converted to a (c)
sign and
the required set loaded or saved as
specified. Saving / Loading set 0 acts on the 286 bytes of UDG's
and Shades.
Note 1. You cannot amend a character from a set or load a set until it has been inserted.
Note 2. The files for sets other
than 0 are a standard 768 bytes spectrum character set. They
could thus
be loaded into / defined with, a
different designer as long as the filename ends in position 10
with a (c)
symbol.
Compress Text
"Compress database (Y/N)?"
is displayed and any reply which dosn't start with "Y"
is assumed to be
negative and causes a return to the
main menu. Otherwise a 222 byte dictionary is inserted into the
databse. The database is then scanned
for occurences of each of 90 common letter groupings which are
replaced with a signle byte token in
the range 154 to 255. This method of compression reduces any text
in the game by approximately 40%.
This could on a text only 128K game provide an equivalent of
160K of memory for the game!
Note 1. When editing text after
compression the cursor will skip 2, 3, 4, or 5 characters due to
the
tokenisation. Corrections should be
typed in full as they will be re-compressed the next time the
compressor is used.
Save Database
The database area is saved to tape as
a sequence of files, two per page. Then tenth position of the
filename is set by PAW as the latters
A to L is sequence for each file.
Verify Database
The files for a databse previously
saved to tape are checked for differences against the database
curently
in memory.
Load Database
The files for a database previously
saved to tape are loaded overwriting any database currently in
memory.
Very Important
If BREAK is pressed or a tape error
is detected during a load then the database held in memory will
be
corrupt and should not be used as it
may corrupt the Editor and Interpreter. Under these curcusmtances
the only Editor option which may be
used safely is Load Database and this should be used until a
database is loaded successfully.
Save Adventure
The Interpreter and database are
saved to tape as a sequenceof files using the filename specified.
They
are saved in such a way that the
Adventure will auto run when loaded from BASIC using LOAD
"" -
without the PAW Editor being present.
Verify Adventure
Verifies that an Adventure has been
saved correctly.
Detailed description of the
Graphic Editor
This section of PAW allows a variety
of operations to be carried out on the drawstring for a location.
When editing, the string is laid out
in memory as follows;
+----------| | | | NEXT | Any commands still undrawn +----------+ | | | | | SPARE | Available memory | | | | +----------+ | END | Temporary end marker +----------+ | | | | | | | DRAW | The main drawstring +----------+
A rubber banded line is used for
drawstring; in the base point of the line (Known as 'point')
shows the
last point plotted, moved to etc, the
rubber banded end of line shows the next position of point or the
start point for a fill / shade etc.
The Editor provides four groups of
commands. Any which insert a command into the drawstring require
a SYMBOL SHIFT key to be held down;
1) Drawstring Commands
ABS MOVE A
Moves point to the x,y position of
end of the line setting only the attributes. This is coded as a
PLOT
with Inverse and Over set on.
PLOT P
Sets the pixel at the end of the line
according to Inverse and Over, then moves point to that position.
REL MOVE R
Moves point to the end of the line
without affecting the screen. This is coded as a relative offset
from
the old point.
LINE L
Draws (or fixes) a straight line from
point to the end of line according to Inverse and Over, then
moves
point to end of the line. The line is
coded as a relative offset from the old point.
FILL F
The area from the end of line
(relative) is filled using solid pixels. Fill works by passing a
pattern to the
SHADE routine so the notes on SHADE
apply also.
All the above use 3 bytes in the database.
SHADE S
The area from the end of lne
(relative) is shaded with one of a large number of patterns. The
database
contains 16 patterns (0-15) which can
be changed using the Character Editor.
The pattern used for shading is
determined as follows:
a) You are asked for 2 pattern
numbers in the range 0 to 15. If you only want the one pattern
then
specify the same number for both
patterns.
b) b) The 2 patterns specified are
OR'd together i.e. they are placed on top of each other.
c) c) If INVERSE was 'on' the
resultant pattern is inverted, i.e. SET / RESET pixels are
swapped.
Note 1. The shade first works in a
downward direction and then in an upward direction. For speed,
when it is going down it doesn't look
up and vice versa. Any areas the shade misses must be shaded
separetely, although careful choice
of the start position for the shade will minimise this.
Note 2. If the area to be shaded
is too complex, then the shade will be abandoned. It has to do
this to
enable it to detect when it comes
across an area which has already been shaded. This an area can
only
be shaded once as an already shaded
area will be too complex to shade again. You should not shade an
area then try to fill in the
background with a fill command, use the Inverse option!
TEXT T
If any character sets have been
inserted in the database, a set number is requested. Then a
character
code in the range 32 to 162 is
requested. This character is placed on screen in the character
square (as
shown by the Grid command) that the
tip of line is contained within. It is mainly designed to allow
"the
fiddly bits" of a picture to be
drawn using the character editor - thus using less memory than
lots of
lines!
Text and Shade use 4 bytes in the database each.
BLOCK B
Causes a block of the currently
selected colours to fill the rectangle of attribute squares which
the line
defines the diagonal of.
Block uses 5 bytes in the database.
2) Colour Commands
INK X
The current ink is set to the value
selected. INK 8 as in BASIC causes all ink to be taken from the
existing screen attributes.
PAPER C
Sets the current paper to the value
selected. PAPER 8 as in BASIC.
FLASH V
The new value of Flash is requested
(0,1 or 8)
BRIGHT Z
The new value of Bright is requested
(0,1, or 8)
all the above use one byte in the databse.
INVERSE I
The state of Inverse (on/off) is
toggled.
OVER O
The state of Over (on/off) is
toggled.
Neither Inverse nor Over use any
memory but their state is encoded as part of each future
instruction
which is affected by them
3) Subroutine Command
GOSUB G
A picture number is requested which
must be in the range 0 to locno. A scale value for the picture is
then requested. This can be from 0 to
7 where the number indicates the size of the picture in eighths -
0
means 'no scale' (i.e. 8/8).
Please note;
a) Scale only affects certain
commands, these are MOVE RELATIVE, LINE, FILL and SHADE.
MOVE ABSOLUTE, PLOT, BLOCK and TEXT
commands will note be scaled or relocated and
should generally not be used in
subroutines (although they will work and can be used usefully
sometimes).
b) You may only nest subroutine calls
to a level of ten. (nesting means calling a subroutine from
within a subroutine).
c) Scale does not affect GOSUB
commands, i.e. if a GOSUB is used within a subroutine the string
drawn will be a fixed size and not
scaled.
d) Calling the same routine you are
drawing will cause a "Limit Reached" error as the limit
of 10
subroutine levels will have been
reached.
Gosub uses two bytes in the database.
4) Editing commands
START >
Puts the Drawstring pointer at the
start of the drawstring.
NEXT \/
Executes next available drawstring
command: if there isn't one the command is ignored.
PREVIOUS /\
Moves the drawstring pointer back one
command and updates the screen.
DELETE
(CAPS SHIFT & 0 ON 48K) deletes
the previous command in the drawstring and updates the screen.
DELETE NEXT
GRAPH(ICS) (CAPS SHIFT & 9 on
48K) deletes the next command if there is one.
GRID Y
Has a toggle action for a character
grid of INK 0, PAPER 7 and PAPER 6. This allows exact positions
of colour boundaries to be taken into
account while drawing.
JOYSTICK J
Toggles the Kempston (tm) joystick
option on and off.
The keys around S move the end of
line around one pixel at a time (this can be accelerated to eight
pixels a time by holding down the
CAPS SHIFT key) thus:
Q W E
A S
Z X C
The joystick should be plugged
into Port 2 of Interface 2 or the Spectrum Plus 2. Alternatively
it can be
plugged into a Kempston (tm)
interface in which case SYMBOL SHIFT & J should be used to
enable
PAW to read it. CAPS SHIFT will also
accelerate the rate of movement on the joystick. The Fire
button will act like SYMBOL SHIFT and
L to draw a line.
Editor Error Messages and their
meanings
Due to the complex nature of PAW many
features can generate errors. Whenever an error is discovered
a message describing the error is
printed in the lower section of the screen. PAW then waits for a
key to
be pressed before returning to the
menu on which that error occurred. There are two exceptions to
this:
1/ After an error during editing a
drawstring; the Drawstring pointer is positioned just before the
command which caused the error (i.e.
a NEXT command will cause the error again). If you are unable
to correct the problem then DELETE
NEXT can be used to delete the erroneous command. Note that
this may still leave further commands
undrawn (which may cause another error).
2/ While an adventure is running;
If the PAW editor is not present then a jump is made to
initialise a
new game after the error report.
Otherwise a diagnostic line is printed on the bottom line of the
screen.
This displays the Process table, Verb
and Noun of the entry and the condact in which the error
occurred. You are then provided with
the flag diagnostics to help confirm where the error occurred.
When ENTER is pressed the normal
error report is printed and a return made to the main menu of
PAW.
When using your own programs in
conjunction with the EXTERN command any of the standard BASIC
errors can occur. Note though that
the line and statement number are not printed - so test your
program
thoroughly without the adventure
present!
PAW also generates several errors of its own which are:
BREAK
BREAK was pressed during a peripheral
operation or while a game was running.
STOP in INPUT
CAPS SHIFT & 6 pressed.
Tape loading error
as BASIC. Note that a tape error
during a load database means that the database is corrupt and
only
reloads should be attempted.
Database full
There is not enough room in the
database for what you were attempting.
Limit reached
The maximum number of locations,
messages, objects, process tables or RAM pages are already
present.
Alternatively the maximum subroutine
or sub-process depth has been reached - 10. This can also occur
if an attempt is made to DOAL while a
DOALL loop is active.
Integer our of range
While drawing a picture a LINE
command has gone out of range. This is usually due to a change of
position of the starting point while
editing.
Out of memory
This indicates that the entry for a
process or connection entry was to large for the buffer
(unliketoly to
occur). Also occurs when attempting
to start a new RAM page on a 48K spectrum, loading a 128K
game on a 48K spectrum or if
insufficient workspace has been left e.g. by setting up fixed
channels
before loading or by writing too big
a program for use with EXTERN.
Invalid Argument
This error is printed when a condact
discovers an illegal value. e.g. An attempt to set flag 38 to an
illegal location, an attempt to PUTIN
/ TAKEOUT on a non container object or to set an object at
location 255 (COPYFO only). But see
point 2 above for diagnostic information.
Note 1. During input the Spectrum will emit a RASP if the screen and / or input buffer is full.
Note 2. If an entry is present in
the database which is too big to fir on one screen, the Spectrum
will
give out a RASP when the entry is
displayed at the bottom of the screen for amending.
Note 3. If an abnormally large
entry is inserted in the connections table using abbreviations
e.g. N 1 W
6 S 4 etc and the abbreviations are
deleted from the vocabulary, the movement entry (when decoded)
i.e.
NORTH 1 WEST 6 SOUTH 4 etc could be
too big for the input buffer. If this happens an out of
memory message will be produced. The
remedy is to reinsert the abbreviations in the vocabulary.
PAW and printers
PAW prints to the printer using
channel #3 (usually "P").
Should this be a ZX thermal
printer (or the Alphacom equivalent) then all printout is
directed to the
required ROM routines. The Thermal
printers only work in 48k mode on a 128K spectrum and will
print exactly what is on screen
including new character sets and so on. The "C" option
on the
characters and graphics menus will
COPY the screen as normal.
On a 128K spectrum the printer
channel defaults to the RS232 port and again PAW will sense this.
All
printout is directed through the port
having filtered the character set thus:
0 - 31 are surpressed except for 7
& 13 which print a CR (13) and 6 (TAB) which prints as a
space
32 - 127 are printed as a space.
128 - 162 are printed as a question
mark ("?")
163 and 164 are expanded to be the
keywords PLAY & SPECTRUM.
165 - 255 are expanded either to the
standard keywords in an uncompressed database, or to the correct
letter groupings in a compressed one.
If you have Interface 1, it is
possible to use the RS232 to print to a printer by opeding the
"t" channel
with the command:
OPEN #3, "t"
before loading the PAW program.
The channel will then operate as described above for the 128K
RS232.
In general it should be possible
to use any printer interface which redirects channel #3 correctly
- with
one proviso; it does not mind having
its output address redirected.
Failing that if you are nifty with
the old m/c you can write a specific printer driver. PAW prints
an
address when it loads called PRTADD.
This gives the address of the vectors within PAW for the
printer system defined as follows
(character is in A):
PRTADD DEFW PRTRET ; Address of
character output
COPVEC JP DOCOPY ; Make this your
screen copy
PRTRET RET ; Put your driver here.
There is free memory up to 29504
decimal for this to be expanded into. Save your driver code from
the
correct address with a filename with
character position 10 set to "A" along with a file of
no bytes with
the same name ending in
"B". You must redirect channel #3 (to anything) to fool
PAW that there is a
non thermal printer connected before
you load it. Then use the Load database option from the main
menu to load your driver (PAW thinks
it's a database an loads both files, one of which is your
driver).
The Essays
There now follows a discussion of
nine topics which rely on several features of PAW in combination
and are thus not so easy to describe
under any one heading:
128K Considerations for those
lucky 128K spectrum owners.
Colour Boundaries deals with the
spikey problem of attributes.
The parser gives a little English
lesson.
Screen Output starts a newline in
descriptions.
Objects will be more flexible after
reading this.
Multi-part games for when memory just
isn't big enough.
Light & Dark throws some light on
the matter?
EXTERN and SCREEN$ are just made for
each other.
PSIs add a bit of character to your
games!
Enough of the frivolity there are pages to fill...
128K Considerations
When loaded, only page 0 is in use
and has about 25500 bytes spare. Pages 1, 3, 4, 6 & 7 are
unused
but can hold 16K each.
Message & Location text,
Connections, Graphics & Default Colours can use pages 1-7,
all the other
tables only use page 0. All table
entries for a location will be held within the same page.
When a location text is inserted
null entries are made in the Connection, Graphics & Default
Colour
tables for that location. The I
option on the Location Text menu always inserts in the highest
used page.
Option B on that menuis used to begin
a new page i.e. it inserts on the next page. You have to decide
when to use B to start a new page but
we would suggest that you use the compressor to gain all memory
available before starting another
page as you cannot insert extra messages etc onto a page once a
new
one has been started - only amend
existing entries.
The start database supplied has
location 0 on page 0 and youy will need to consider whether
location 1
should be on a new page bearing in
mind that ll the other tables can only use page 0. We would
advise
all messages and locations are on
pages 1 and up, as page 0 can soon become filled with vocabulary
etc.
A similar thing applies to the
message text table; I inserts on the highest selected page, B
begins another
page if it has been initialised by
putting a location on it!
If you want your game to run on a 48K spectrum then you must not use any page other than 0.
Colour Boundaries
Probably one of the most difficult
aspects of using graphics on the Spectrum is the problem of the
attribute colour system.
This essentially means that only
two colours can be used in any one 8x8 pixel group. The areas are
shown by the GRID option in the
graphics editor. The two colours are the PAPER and INK, the
colours
of reset and set pixels respectively.
Both Paper and Ink can be any of eight values for each 8x8 pixel
group.
The fill and shade routines fill
in a defined area with a pattern of set and reset pixels. So if
you use
different INK and / or PAPER colours
for two adjacent fills or shades, you will get a coarse stepping
effect. This is due to the colours
for the second fill affecting pixels in the groups which were set
by the
first.
This effect can be overcome in one of four main ways:
1 / Ignore it! This system is used
on some pictures in the TEWK game. The effect is minimised by not
having shaded or filled areas
directly adjacent to each other.
2 / Use shade fully. The shade
system can be used along with just two colours to create very
effective
pictures using varying densities of
shade.
3 / Careful positioning as used in
the tutorial manual. All areas are defined on exact attribute
boundaries. This has the effect of
creating very cubist pictures.
4 / Alternate colour. This allows
two areas of solid colour (not shades) to be adjacent to each
other. It
sounds complicated but in principle
is fairly straightforward: the diagram shows this far more simply
than reams of text.
The outlines of area A and B are
drawn. Area A is filled using an INK of the first colour
required. Area
B is filled using an INK of the
second colour required. The block command is used on the
rectangle (C)
with the PAPER set to be the second
colour required and an INK of 8. This leaves area A and B
unchanged. The colouring of the PAPER
makes the join look continuous.
The Parser
The parser works by scanning an input
line (up to 125 characters) for words which are in the
vocabulary, extracting 'Phrases'
which it can turn into Logical sentences.
When a phrase has been extracted,
the Response and Connections tables are scanned to see if the
Logical Sentence is recognised. If
not then system message 8 ("I can't do that") or system
message 7 ("I
can't go in that direction")
will be displayed depending on the Verb value (i.e. if less than
14 then
system message 7 will be used) and a
new text input is requested. A new text input will also be
requested if an action fails in some
way (e.g. an object too heavy) or if the writer forces it with a
NEWTEXT action. The results might
otherwise be catastrophic for the player. e.g. GET AXE AND
ATTACK TROLL, if you don't have the
axe you wouldn't really want to tackle the Troll!
If the LS is successfully executed
then another phrase is extracted or new text requested if there
is no
more text in the buffer.
Phrases are separated by conjugation ("AND" & "THEN" usually) and by any punctuation.
A Pronoun ("IT" usually)
can be used to refer to the Noun/Adjective used in the previous
Phrase - even
if this was a separate input. Nouns
with word values less than 50 are Proper Nouns and will not
affect
the Pronoun.
The Logical Sentence format is as follows:
(Adverb) Verb (Adjective1 (Noun1)) (preposition) (Adjective2 (Noun2))
where bracketed types are
optional, i.e. the minimum phrase is a Verb (or a Conversion Noun
- which is
a Noun with a word value < 20 -
which if no Verb is found in a phrase will be converted into a
Verb e.g.
NORTH). If the verb is omitted then
the LS will assume the previously used verb is required. i.e. GET
SWORD AND SHIELF will work correctly!
- the pronoun will be the first object in a list like this,
SWORD in the example.
Note that the phrase does not strictly have to be typed in by the player in this format. As an example:
GET THE SMALL SWORD QUICKLY
QUICKLY GET THE SMALL SWORD
QUICKLY THE SMALL SWORD GET
are all equivalent phrases producing the same LS. Although the third version is rather dubious English.
A true sentence could be:
GET ALL. OPEN THE DOOR AND GO
SOUTH THEN GET THE BUCKET AND LOOK IN
IT.
which will become five LS's:
GET ALL
OPEN DOOR (because THE is not in the
vocabulary)
SOUTH (because GO is not in the
vocabulary)
GET BUCKET
LOOK BUCKET (from IT) IN
(preposition)
Note that DOALL will not generate
the object described by Noun(Adjective)2 of the Logical sentence.
This provides a simple method of
implementing EXCEPT. e.g. GET ALL EXCEPT THE FISH, it has
the side effect of not allowing PUT
ALL EXCEPT THE FISH IN THE BUCKET, as this has three
nouns!
Screen Output
Character sets are selected in text
by selecting a colour 0-5 then a single DELETE to generate ESCCs
0-
5, and will only take effect if a
corresponding set has been inserted.
ESCC 7 is a true newline (but does not reset colours as it is part of a message).
ESCC 6 works as a TAB but should
be used with care as it will often be suppressed by the text
formatter when printing.
Colours and character sets
selected within text will stay in force until a NEWLINE action.
e.g. To print
the number of coins carried by the
player (held in flag 100 say); If message 1 contains a RED PAPER
control code then an entry in
Response (or a Process table) of:
COINS MES 1 ; "<RED>You
are carrying"
_ PRINT 100
MESSAGE 2 ; " coins."
DONE
will result in the entire message
being printed in red. This is called a compound message and can
be
used successfully to create neat
displays.
Objects
Underlines in text will be converted
during gameplay into a description of the last object referenced
by
GET, DROP, DESTROY etc. This is
mainly to deal with the fact that GET, DROP etc report their
success (or failure!) but can be used
usefully for examining objects and other automatic reports.
Flag 53 is used to control the way
objects are displayed when the LISTOBJ and LISTAT actions are
used. If the flag is set to 64 (i.e.
Bit 6 is set) then objects will be listed without newlines
between them,
forming a valid English sentence -
compound listing.
The formats are as follows:
SM53 ("nothing") - can
only occur with LISTAT
object SM48(".")
object SM47(" and ") object
SM48(".")
object SM46(", ") object
SM47 (" and ") object SM48(".")
In addition, Bit 7 of flag 53 will
be set (i.e. flag will be grater than 127) if any objects were
printed.
This allows you to determine whether
or nor a NEWLINE is required to reset colours.
A LISTAT action will usually be preceded by a message.
The description of object is
constructed from the full description given in the object text
table. The
preferred format for an object
description is:
indefinite.article (adjective) noun . extra text
where; the indefinite article is
"A" or adjectives "An" or "Some".
The Adjective and the Noun should
have a lower case letter e.g. "A
small key", "Some sand" or "An orange. Rather
mouldy'. PAW extracts
a description of the object in two
ways:
1/ For GET, DROP etc (i.e.
"_") the indefinite article is skipped and the
description printed upto (but
not including) the first full stop,
e.g. "I now have the small key."
2/ For a compount list of objects
the indefinite article is forced to start with a lower case
letter and the
description printed upto (but not
including) the first full stop. e.g. "In the bag is a small
key.".
Obviously if you don't use
underline or compound listings, then you are free to describe
objects any
way you like.
Important: If an object is to be a
container; there must be an unused location with the same number
for
PAW to use as the "inside"!
i.e. Object objno. 1 would need Location locno. 1 - Not
forgetting to mark
it as a container ("C") on
object weight!
Creating Multi-Part Adventures
In order to create a larger (and thus
more interesting) play area in an adventure, without sacrificing
the
quality of the description, you can
split the game into smaller sections. It is best to do this with
a game
that lends itself to having several
areas, with only one join between each, this is called a
bottleneck. e.g.
a game where setting sail on a boat
is the final task in the first part.
To allow the score, turns taken
and other information to be carried forward into the next game
you must
use the LOAD / SAVE game position
actions. In order to load a game position into a different game
to
ahat which it was saved from, you
need the same number of locations and objects in each part. In
addition, all objects which may
possibly be carried forward by the player, must have the same
description in all parts.
Let's take a game with 120
locations, that is to be split in half, thus requiring 60
locations in each part.
Actually location 60 will exist in
both games as the transition location (where the player starts
and
finishes) and a spare flag (say 26)
will be used to indicate which part of the game a position is
from. So
when the player completes part 1 they
are moved to location 60 and flag 26 is set to 1 to show it.
The setup for part 1 would be:
Location 60
End of Part 1 - Prepare a tape to
save your position. (You may save more than one copy if you
like).
Please LOAD part 2 and follow the
onscreen prompts.
Process 1
END _ AT 60 ; End of game?
_ LET 25 1 ; Valid position from part
1.
SAVE
And in part 2:
Location 0
Part 2 - Prepare to load tape with
saved position
Location 60
Any introduction wanted for Part 2.
Process 1
START _ AT 0 ; Just starting?
LOAD ; Will then be at another
location
START _ NOTEQ 26 ; Not a valid
position from part 1
GOTO 0 ; So request another load
DESC
START _ AT 60 ; Just loaded a
valid position
ANYKEY ; Wait until introduction read
RESET 1 ; Start game properly at
location 1
The RESET action does a DESC of
the new start location automatically, after setting all objects
that
aren't carried, worn or at location
60 to their starting position. Note that you should insert any
CLEAR
actions for flags between the ANYKEY
and the RESET as the flags are not affected by the RESET.
Light and Dark
Darkness is becoming something of a
cliche in adventures these days, but used correctly it can add to
the sense of realism considerably.
Within PAW, darkness is created by
setting flag 0 to a value other than 0. This must be done
whenever
the player moves into and out of
darkness, i.e. the move must be done with a GOTO in the Response
table, to allow the SET or CLEAR
action to occur.
If the player is being provided
with a source of light then object 0 is the easiest way of
implementing it.
A source of light does not have to be
a torch or candle, with a little imagination it can be infra-red
glasses or a wide beam laser!
Take for example the creation of a
night and day cycle, over 24 time frames which we will assume are
equivalent to 1 hour.
The entries required in Process 2 are:
_ CYCLE EQ 5 0 ; End of cycle
LET 5 24 ; Start the counter again
_ NIGHT EQ 5 18 ; Nightfall
SET 0
MESSAGE X
_ DAY EQ 5 6 ; Daybreak
CLEAR 0
MESSAGE y
Importantly if part of the game is
underground, or inside a building, don't forget to determine if
the
player can actually see nightfall and
daybreak from where they are, before printing the messages.
EXTERN and Loading screens
The EXTERN command can be used to
call either your own machine language programs or a section of
a BASIC program. This feature can be
utilised only in a final game, as the 4K of memory previously
occupied by the main menu becomes
available (the other 2K is PAW's workspace so hands off!) The
important address is the value
printed when PAW loads called EXTVEC. You must use the value
given
on the copy of PAW you save the final
game from, or chaos will ensue.
For machine coders only: In order
that EXTERN can execute machine code routines you must POKE
the three bytes at EXTVEC with a JP
to our start address. Register IX must be preserved as it points
at
Flag 0. All others may be destroyed,
but SP must be balanced. Register A on entry contains the
parameters to the EXTERN command. If
you save the two bytes at EXTVEC+1 they point to the
routine which calls a BASIC program -
the line number must be in A.
For BASIC users: a POKE extvec,195
- after loading the interpreter file - will enable any EXTERN
actions to execute the BASIC line
(100+parameter) e.g. EXTERN 10 will goto line 110 in BASIC. To
return to the next condact a STOP
command in BASIC is required. You cannot use CLS in BASIC (or
m/c), but address EXTVEC+3 contains a
routine to do this. i.e. RANDOMIZE USR EXTVEC+3 will
clear the screen. In addition
EXTVEC+12 contains the line number to print the filenames of the
database files on and EXTVEC+9 is the
load database and start game entry point.
As an example the following
program (without the REM's) must be saved to a fresh tape with
SAVE
"gamename" LINE 10:
10 REM load game
15 BORDER 0: PAPER 0: INK 0: REM so
filenames are invisible
20 CLEAR 29856: REM this is maximum
value for RAMTOP.
25 LET extvec=?????: REM whatever it
is...
30 LOAD ""SCREEN$: PRINT AT
19,0;: REM stops damage to pic!
40 LOAD ""CODE: REM load
interpreter file
50 POKE extvec,195: REM enable EXTERN
60 POKE extvec+12,20: REM filenames
on line 20
70 RANDOMIZE USR (extvec+9): REM load
database and start game
100 REM line that is called by EXTERN
0
110 PRINT "hello from
BASIC": STOP
355 REM line that is called by EXTERN
255!
Lines 100-355 could contain GOTO statements if required.
Save your SCREEN$ immediately
after the program on the tape. Then from within PAW save the
Adventure (using option A) after
that.
Important there must be at least
2000 bytes spare for PAW's workspace or your BASIC program will
start to disappear! RAMTOP may be
lowered to contain your machine code but 2K must be spare!
Pseudo-Intelligence
The main thing to remember is that a
character (or PSI) is a word in the Vocabulary (usually a Noun
with a value less than 50 so as to be
a Proper Noun). Some flags, a series of messages and some entries
in one or more Process tables. One
flag shows where they are, the messages provide information about
their actions and the process table
entries tie it all together.
So imagine a character called
Sanec who can walk around independently. He is described in the
vocabulary as SANEC (word value 25,
Noun). Flag number 20 is used to give his location. Process
table 3 will deal with speech to him.
While Process table 4 will deal with his movements and actions.
The following entries allow him to
move around when you ask him to. After a short time he will get
"bored" and vanish in a
puff of smoke!
Message 1
Sanec did not seem to understand what
you said.
Message 2
No one of that name here!
Message 3
Sanec replies "hello" in a
gruff voice.
Message 4
Sanec wanders that way as he has
nothing bettern to do.
Message 5
Sanec the wizard is here.
Message 6
Sanec 'politely' ignores what you
say.
Message 7
Sanec turns to face you and in his
gruff voice announces; "I'm bored with all this, I'm off to
a bigger
game" and promptly vanishes in a
puff of green smoke!
First; Sanec's presence at a
location must be announced. So in Process 1 (which is called
after every
describe of a location) we check if
he is here i.e. flag 20 (his location) is the same as flag 38
(our
location). Note that we ensure we are
not at location 0 as this is always an introduction screen.
SANEC _ SAME 20 38 ; Ensure Sanec
is here
_ NOTAT 0 ; Player is not in location
0
MESSAGE 5 ; Say Sanec is here
To deal with speech to Sanec, we need entries in Response as follows:
SAY SANEC PREP TO ; This could be
imitted to allow
; Short Verb Noun sentences
; to be understood
SAME 20 38 ; Make sure Sanec is here
PROCESS 3 ; Deal with any speech
DONE
SAY _ PREP TO
MESSAGE 2 ; no one of that name here!
DONE
The following entries in Process 3:
* * PARSE ; This entry always
carried out
; convert the input string to a
; LS
MESSAGE 1 ; PARSE comes here if it
fails
; to find a valid phrase
DONE ; Note that the LS is corrupt
; and no further table entries
; must be executed
HELLO MESSAGE 3 ; Assuming HELLO
is a verb in
; vocab
DONE ; so that SAY TO SANEC
; "HELLO" works
_ _ LT 34 14 ; A movement word
said to
; Sanec?
MOVE 20 ; See if a connection for
that
; way
MESSAGE 4 ; Come here and tell player
if
; so
_ _ MESSAGE 6 ; He ignores you
(i.e. nothing
; else)
Obviously many more entries would
be required to give Sanec an appearance of understanding speech,
but with a few clever entries he can
give a wide variety of responses.
Finally; to give Sanec a chance of disappearing when bored, we need an entry in Process 4 of:
SANEC _ EQ 20 2 ; At location two?
CHANCE 10 ; 10% chance
SET 20 ; Location 255 does not exist
AT 2 ; are we where he was?
MESSAGE 7 ; POOFF! - tell player he
; disappears
And an entry in Process 2 to call table 4 regularly:
SANEC _ PROCESS 4
In this way a very convincing
character can be built up. They add a great deal to the sense of
relism in
games. Especially if interaction with
them is required as part of the solution.
Graphic Editor Commands
Occasionally when moving the line at
speed it will disappear, this is due to a beat frequency of
update
with screen flyback.
Moving the end of the rubber banded line is achieved with:
Q W E
A D
Z X C
at 1 pixel per move. Alternatively
use Interface 2 / Plus 2 joystick port 2 or Kempston(tm)
interface
(SYMBOL SHIFT & J).
Hold down the CAPS SHIFT key to accelerate to eight pixels per move.
The drawstring editing commands:
Cursor Right (CAPS SHIFT & 8)
- Start of drawstring
Cursor Down (CAPS SHIFT & 6) -
Next command
Cursor Up (CAPS SHIFT & 7) -
Previous command
DELETE (CAPS SHIFT & 0) - Delete
previous command
GRAPHICS (CAPS SHIFT & 9) -
Delete next command
All the following commands require SYMBOL SHIFT to be held down unless otherwise specified.
The toggles:
I Inverse Toggle
O Over Toggle
Y Grid Toggle
J Kempston(tm) joystick toggle
The next commands all insert into the database:
A Absolute Move (a PLOT with I and
O selected)
B Block in rectangle attribute area.
Diagonal defined by line.
F Fill area from end of line. (See
footnote)
G Gosub to location number with scale
X Ink (produces prompt for Ink
selection)
L Line fix (draws rubber banded line)
C Paper Select
P Plot point at end of line
R Relative Move point to end of line
S Shade an area of screen from end of
line with pattern
V Flash Select
Z Bright Select
T Text character on screen, selects
character and set no.
Note: Fill and Shade are not completely re-entrant. Fill is a shade with all pixels in pattern set.
ENTER on its own to finish editing session.
The System Messages
The majority of system messages
contain ESCC 7's to allow correct spacing on the screen.
SM0 - is used instead of the
location description when it is dark.
SM1 - is printed by LISTOBJ if at
least one object is present.
SM2 to SM5 - are the four input
prompts which are selected randomly unless flag 42 is set to be a
valid
message number.
SM6 - is produced by the parser when
no further phrase can be understood.
SM7 - is produced if no action was
carried out (or NOTDONE was) in Response when the Verb is < 14
SM8 - is produced if no action was
carried out (or NOTDONE was) in Response when the Verb is > 13
SM9 to SM11 - are printed by the END
action.
SM12 - printed by QUIT
SM13 and 14 - are printed by the END
action
SM15 - the OK action message.
SM16 - the ANYKEY action message.
SM17 to SM20 - are the TURNS action
messages.
SM21 and SM22 - are the SCORE action
messages.
SM23 and SM29 - are the first of many
messages produced by the object manipulating actions.
SM30 - the positive response expected
by END and QUIT.
SM31 - the negative response expected
by END and QUIT.
SM32 - produced when a screen full of
text has appeared.
SM33 - the input marker.
SM34 - the cursor.
SM35 - displayed when a timeout
occurs
SM36 to SM45 - are more messages
produced by the object manipulating actions.
SM46 - the link between objects when
listing continuously
SM47 - the final link between the
last two objects when listing
SM48 - the termination of a list of
objects (printed by both LISTOBJ and LISTAT, so take care.)
SM49 and SM50 - yet more object
messages
SM51 - the termination for a compound
sentence on PUTIN / TAKEOUT (and AUTOP / AUTOT)
SM52 - a final object message
SM53 - message for LISTAT action if
no objects found.
SM54 onwards are free to be
inserted for your own use. PAW on other machines may use more
messages, so bear this in mind if you
intend transferring the adventure to another version. E.g. PAW
under CPM uses messages 54 to 60!
Function of PAW Flags
The normal flags are free for use in
any way in games. The auto decrement flags (2 to 10) are also
free
for use, but be sure you know in
which situations they are reduced before using them. Other flags
should mostly only be set using the
appropriate action, but useful tests can be carried out on their
contents.
Flag 0 - When non zero indicates
game is dark (see also object 0)
Flag 1 - Holds quantity of objects
player is carrying (but not wearing)
The following flags are
decremented if non zero by PAW:
Flag 2 - When a location is described
Flag 3 - When a location is described
and it's dark (Flag 0 not 0)
Flag 4 - When a location is
described, it's dark and object 0 is absent.
Flag 5 to 8 - Every time frame (i.e.
every phrase / timeout)
Flag 9 - Every time frame that it's
dark
Flag 10 - Every time frame that it's
dark and object 0 is absent
Flag 11 to 28 are free for use in your own games
Flag 29 holds Picture Control
flags
Bit 7 - Set this to force picture to
be drawn (LOOK)
Bit 6 - Set this to always draw
picture (PICS ON)
Bit 5 - Set this to never draw
picture (PICS OFF)
this is set by using the GRAPHIC
action
Flag 30 - Score flag
Flag 31 / 32 (LSB/MSB) holds number
of turns player has taken (actually this is the number of phrases
extracted from the player's input).
Flag 33 - holds the Verb for the
current logical sentence
Flag 34 - holds the first Noun in the
current logical sentence
Flag 35 - holds the Adjective for the
first Noun
Flag 36 - holds the Adverb for the
current logical sentence
Flag 37 - holds maximum number of
objects conveyable (initially 4). Set using ABILITY action.
Flag 38 - holds current location of
player.
Flag 39 - holds current top line of
screen
Flag 40 - holds screen mode (range 0
to 4..) set with MODE action. Also bit 7 - Forces no change of
Border, Bit 6 Produces
"More.." when screen fills.
Flag 41 - holds line number for split
(if not in range 4-24 then 12 used) this is set by the PROTECT
action to be the current screen line.
Flag 42 - holds prompt to use (a
system message number - 0 selects one of four randomly. Set by
the
PROMPT action).
Flag 43 - holds the Preposition in
the current logical sentence.
Flag 44 - holds the second Noun in
the current logical sentence.
Flag 45 - holds the Adjective for the
second Noun
Flag 46 - holds the current pronoun
("IT" usually) Noun
Flag 47 - holds the current pronoun
("IT" usually) Adjective
Flag 48 holds Timeout duration
required
Flag 49 holds Timeout Control flags
Bit 7 - Set if timeout occurred last
frame
Bit 6 - Set if data available for
recall (not of use to writer)
Bit 5 - Set this to cause auto recall
of input buffer on timeout
Bit 4 - Set this to print buffer on
exit, (for use with Bit 3)
Bit 3 - Set this to take input from
lower screen
Bit 2 - Set this so timeout can occur
on ANYKEY
Bit 1 - Set this so timeout can occur
on "More..."
Bit 0 - Set this so timeout can occur
at start of input only
Set using INPUT and TIME (as is flag 48), TIMEOUT tests bit 7 of this flag.
Flag 50 - holds locno. for DOALL
loop. i.e. value following DOALL
Flag 51 - holds last object
referenced by GET / DROP / WEAR / WHATO etc. This is the number
of
the currently referenced object as
printed in place of any underlines in text.
Flag 52 - holds player's strengths
(maximum weight of objects carried and worn - initially 10)
Flag 53 - holds object print flags
Bit 7 - Set if any object printed as
part of LISTOBJ or LISTAT
Bit 6 - Set this to cause continuous
object listing i.e. LET 53 64 will make PAW list objects
on the same line forming a valid
sentence.
Flag 54 - holds the present location
of the currently referenced object
Flag 55 - holds the weight of the
currently referenced object
Flag 56 is 128 if the currently
referenced object is a container
Flag 57 is 128 if the currently
referenced object is wearable
Flag 58 & 59 should be avoided as
they will be used for expansion.
Flag 60 to 255 are available for your
own use.
The Condacts
Conditions:
AT locno ; ensure player at
specific location
NOTAT locno
ATGT locno ; higher location than
specified
ATLT locno ; lower...
PRESENT objno
ABSENT objno
WORN objno
NOTWORN objno
CARRIED objno
NOTCARR objno
ISAT objno locno+
ISNOTAT objno locno+
ZERO flagno
NOTZERO flagno
EQ flagno 0-255
NOTEQ flagno 0-255
GT flagno 0-255
LT flagno 0-255
SAME flagno flagno
NOTSAME flagno flagno
ADJECT1 word
ADVERB word
PREP word
NOUN2 word
ADJECT2 word
CHANCE 0-99 ; random possibility
of success
TIMEOUT
QUIT
Actions (Those marked 4 are type 4, 3 are type 3, 1 are type 1)
GET 4 objno
DROP 4 objno
WEAR 4 objno
REMOVE 4 objno
CREATE objno
DESTROY objno
SWAP objno objno
PLACE objno locno+
PUTO locno+
PUTIN 4 objno locno.
TAKEOUT 4 objno locno.
DROPALL
AUTOG 4
AUTOD 4
AUTOW 4
AUTOR 4
AUTOP 4 locno
COPYOO objno objno
COPYOF objno flagno ; copy
position of object to flag
COPYFO flagno objno
WHATO ; convert Noun1(Adjective1)
to
; current object
WEIGH flagno objno ; weight of object
is put in flag
SET flagno
CLEAR flagno
PLUS flagno 0-255 ; add value to flag
MINUS flagno 0-255
LET flagno 0-255
ADD flagno1 flagno2 ; contents of
flagno1 added to flagno2
SUB flagno1 flagno2
COPYFF flagno1 flagno2
RANDOM flagno ; set to random number
from 0-99
MOVE flagno ; adjust contents of flag
according to
; the LS Verb and the Connection
; table entry for location, that the
; contents specify. (Allows movement
; of PSI's)
GOTO locno
WEIGHT flagno ; Weight of objects
carried & worn
; are put in flag
ABILITY 0-255 0-255 ; Set conveyable
objects and strength
MODE 0-4 0-3
LINE 0-20 ; Set screen line to split
picture
GRAPHIC 0-3
PROMPT sysno ; Prompt on input. 0 is
random
INPUT 0-7
TIME 0-255 0-7
PROTECT
PRINT flagno ; display contents of
flag on screen
TURNS
SCORE
CLS
NEWLINE
MES mesno ; message without a newline
MESSAGE mesno ; message with a
newline
SYSMESS sysno ; system message
without newline
PICTURE locno ; Display picture
(without CLS)
PAPER 0-9
INK 0-9
BORDER 0-7
CHARSET 0-255 ; Select character set
(if inserted)
SAVEAT ; Save current print position
BACKAT ; return to it
PRINTAT 0-20 0-31 ; Set a new print
position
LISTOBJ ; List objects at current
location
LISTAT locno+ ; List objects at
specified location
INVEN 3
DESC 1
END ; Type 2, Exits table to restart game
DONE 3
NOTDONE 3
OK 3
SAVE 1
LOAD 1
RAMSAVE
RAMLOAD flagno
ANYKEY
PAUSE 0-255 ; Delay program for n/50
of a second
PARSE ; Convert input string to
valid LS
NEWTEXT ; Force the loss of remaining
phrases
BEEP 0-255 0-255
PROCESS procno
DOALL locno+ ; Generate
Noun(Adjective)1 for each
; object at Location locno.
RESET 1 locno ; Move player and
present objects,
; reset others to initially at - used
; to chain games with LOAD
EXTERN 0-255 ; Call external program
Where:
locno. is a valid location number.
locno+ also allows the use of; 252
(not created), 253 (worn), 254 (carried) and 255 which is
converted
into the current location of the
player.
mesno. is a valid message.
sysno. is a valid system message.
flagno. is any flag (0 to 255)
procno. is a valid sub-process
number.
word; is a word of the required type,
which is present in the vocabulary, or "_" which
ensures no-word -
not an anymatch as normal.
d