Life and Times of the Inform Library 3rd July 1995 ==================================== This modification history takes release 5/5 of the Inform library as a base, and runs up to release 5/11. 5/5 is the state described in the first edition of the Designer's Manual and 5/11 the one in the (forthcoming) revised edition; thus, everything in this file will soon be integrated into the current documentation. Thanks to Gareth Rees, Mike Threepoint, Torbj|rn Anderson, Brendon Wyber, Robert Dickau, Brad Jones, David Wagner, Robert Stone, Matthew Russotto and many, many others. Changes in Release 5/6 (941112) =============================== 1. The game banner is tidier and a line shorter (some people felt the old one overdone: use the command "version" for more code numbers) 2. EnglishNumber printing fixed up to work nicely across the whole range of signed integers (i.e. about plus-minus 30000), with "forty" correctly spelt this time: e.g. "minus twelve thousand, three hundred and eight" 3. The bug "the game crashes if you try to take what you're sitting on or in" is fixed 4. Two new bits are available for WriteListFrom styles. ISARE_BIT prints " is " or " are " before the list, according to its size, and CONCEAL_BIT (which only works if WORKFLAG_BIT isn't used) misses off items which have "concealed" or "scenery" 5. Containers now aren't called "open" or "closed" in lists unless actually "openable": thus, messages like "a paper cup (which is open but empty)" will now read "a paper cup (empty)" 6. Concealed or scenery items now not mentioned inside vehicles or on top of things (see (4)!) 7. The "found_in" property is enhanced. If an object O1 is given in the found_in list of O2 which isn't a room, then O2 is counted as being in the same room as O1, wherever that is at the moment. (But be warned: this is only updated when the player changes rooms.) Moreover, the "found_in" property of O can instead of a list of places be a routine. This returns true if O should be in location, false otherwise. For instance, Object Sun "Sun", with .... found_in [; if (location has light) rtrue; ], has scenery; This saves bother with long lists of places, and also makes it much easier for objects to spread out or contract (like fire, or flooding) in play. 8. A bug making YesOrNo() corrupt a customised status line has been removed 9. Under earlier library files, returning 0 from a token-parsing routine was illegal and might hang the parser (see p. 41 in the Designer's Manual for the old specification). Returning 0 is hereby legalised and indicates "accept the text the word marker has been skipped over, and count it as not specifying any particular object or number". For example, given [ PolyAdj w; w=NextWord(); if (w=='on' or 'at' or 'in') return 0; return -1; ]; the token PolyAdj will accept "on", "at" or "in" as alternative choices of adjective (and forget which one the player actually typed). Similarly, [ Anything w; while (w~=-1) w=NextWord(); return 0; ]; makes the token Anything accepts the entire rest of the line. 10. The grammar "shut off", "climb up", "close up", "dig", "dig with" has been added 11. Taste and Touch are now required to take objects: as a result the old TouchThing action has gone, and there is simply a Touch action. (Strictly speaking this is an incompatible change but hardly anyone has used these actions anyway.) 12. The Escape key now acts as Q to get out of menu displays (if your interpreter is well enough written to recognise an escape key) 13. A convenience (but also problem) is that the Receive fake action is generated both when the player tries to put an object in something, or on it. This is no problem unless the recipient is trying to be both at once, in which case it may need to know why the Receive has been generated - i.e., which the player's trying to do. The "right" solution would be to have two different fake actions, but that would be a rather incompatible change and make a certain amount of existing code work differently. Instead, a variable called "receive_action" is set to either ##PutOn or ##Insert depending on which is causing the Receive to happen. 14. Several people have asked for easier ways to have several kinds of containment at once, all on the same object - on top, inside, under, behind, component parts of, etc. For these (and other) purposes a brand new property called "add_to_scope" has been added. Anything listed under this property is also in scope when the parent object is. (This also has consequences for light considerations.) See the modest example "A Nasal Twinge" for two applications of this. Note for true scope hackers: this scope addition does _not_ occur if the object is moved into scope by the programmer explicitly calling PlaceInScope (since this must allow completely arbitrary scope selections), but that it does happen when objects are moved in scope by calls to ScopeWithin(domain). The "add_to_scope" property is aliased, so there's no cost in property consumption. 15. Trying to type "undo" on the very first turn now produces a more sensible error message. 16. 5/5 had an especially embarrassing bug - "go north" didn't work! Which goes to show how thoroughly hooked on abbreviations we all are now, because hardly anybody noticed. 17. The initial room description (printed after the game banner) is now properly done with a Look action (in particular, before and after routines are invoked). This is in case some horrid "before" hack is being applied to the description of the first location. 18. Likewise, the library now works correctly if the game begins in darkness (Steve Meretzky is fond of this trick - e.g. "Hitchhikers", "Sorcerer") 19. "out" used not to work properly in a dark room with an out map connection, but now does 20. A somewhat brutal test (Torbj|rn Anderson constructed 450 daemons!) revealed that the daemon/timer routines stored object numbers in bytes rather than words (thus getting them wrong in big games): not any more they don't 21. It is now legal to return 3 from a routine attached to DoMenu (which usually prints some text out, such as a hint: return values of 0 or 1 make the game wait for a space then return to the menu, 2 makes the game return directly): this makes the game quit the menu altogether as if Q had been pressed (which is useful for juggling submenus around). Changes in Release 5/6 (941117) =============================== 22. "You open the box, revealing ." bug fixed (when box is empty) 23. A character got seriously corrupted in the timers routines: fixing this was urgent, hence the rapid re-release Changes in Release 5/7 (941214) =============================== 24. add_to_scope can now take a routine instead of a list of objects. This routine has to call AddToScope(obj) for each obj it wants to add to the scope. (It may not use ScopeWithin or any other scoping routines) 25. The direction objects now have the general-purpose "number" property provided, as it's sometimes convenient to have a scratch variable for each direction (when programming mazes, for instance). 26. If the constant WITHOUT_DIRECTIONS is defined before inclusion of the library files, then 10 of the default direction objects are not defined by the library. The designer is expected to define alternative ones (and put them in the "compass" object); otherwise the game will be rather static. (The "in" and "out" directions are still created, because they're needed for getting into and out of enterable objects.) 27. The routine ChangeDefault(property, value) dynamically changes the game's default value for that property (i.e. the value that property has for any object not explicitly giving a value of its own). For instance, ChangeDefault(cant_go, "You're a Master Adventurer now, and still \ you walk into walls!"); 28. The reverse-order form of "show" didn't work when addressed to a third party, as in charles, show diana the phone bill but now does. 29. Very subtle bug in object-name printing (it had a peculiar and very rare side-effect which I think only turned up when using odd combinations of debugging commands, and took me ages to find!) fixed. 30. The not very sad demise of another piece of Inform antiquity: the use of the "special" token in the library grammar. The only substantial use left was in the grammar for looking up or consulting things, like books (an old Curses mainstay). Now it's tricky to parse lines like look up figure 18 in the engineering textbook because almost anything could appear in the first clause, and even its format depends on what the second clause is. So the new arrangement is: if an object wants to be "consultable", it should have a before rule for the "Consult" action. The Consult action will happen when the player types, for instance, look up in read about in consult about and the object has to parse the part itself. (Note that "second" doesn't hold any value in a Consult action; internally, the part is treated as an adjective by the parser.) To help the object to do this, variables are set up: consult_from - number of the first word in the consult_words - number of words in the (which must be at least 1) It can then use NextWord(), TryNumber(word-number) and the like to decide on the topic. If you really need more elaborate topic-parsing then grammar replacement is probably a better bet. 31. The verbs "read" and "examine" are now separated - this has been a popular request for about a year now! They still both ordinarily generate the Examine action, but it is now possible to add or replace grammar for "read" without doing so for "examine" at the same time. Consequently one may now easily create a separate Read action, if required. E.g.: Attribute legible; Object textbook "textbook" with name "engineering" "textbook" "text" "book", description "What beautiful covers and spine!", before [; Consult, Read: "The pages are full of nasty equations which \ make no sense to you."; ], has legible; [ ReadSub; <>; ]; Extend "read" first * legible -> Read; Note that "read" is automatically translated to "examine" for anything which doesn't have "legible", or indeed does but doesn't provide any "before" rule for Read. 32. Many actions (all those which do something substantial and then print a message saying they've done it), viz.: Take, Drop, Insert, PutOn, Remove, Enter, Exit, Go, Unlock, Lock, SwitchOn, SwitchOff, Open, Close, Wear, Disrobe, Eat now consult a variable called "keep_silent". If this is 1, they say nothing in the event of _success_ (if they fail, as they may do in many different convoluted ways, they still complain out loud). It is essential to reset this variable to 0 after use. This feature makes implicit actions much easier to "properly" implement, i.e. to implement without bypassing any lurking game rules. 33. (As indeed here.) The library used to be a bit casual about putting items away automatically into the SACK_OBJECT (if there was one defined), but now it applies the full normal rules by causing an Insert action. Thus, the sack needs to be open, any odd behaviour coded up for the sack will now work, the sack's capacity cannot be exceeded and so on. 34. The Enter and Exit actions sometimes missed possible location "after" rules; they've now been tidied up. 35. Silly bug in scoring "scored" objects (picked up by take all) fixed. 36. "your" is now understood in some contexts by the parser: so that george, give me your ukelele works (if someone called George is holding a ukelele). 37. In 5/6 and before, if you put a green box inside a red bag, and then tried to put the red bag into the green box, they would collapse in on themselves into a black hole and vanish from the game. (An amusing thing to do is then to use the "tree" debugging command on the green box.) The library now insists on the Axiom of Foundation (i.e., won't let you put something indirectly inside or on top of itself). Changes in Release 5/7 (941220) =============================== 38. The "the box of tarot cards is empty already." sentence now capitalises the "The". 39. Bug in the parser fixed. Occasionally grammar like ... * scope=MicroScope "at" noun -> ... would mistakenly apply the MicroScope scope rules to the second, plain noun token. This no longer happens. 40. Minor darkness bug (to do with getting out of enterable objects when in a dark place) fixed. 41. Single rather than double new-line now printed when light returns to the game (after all, some people have small displays). 42. If a "supporter" (say, a mantelpiece) holds up only items which have "scenery" or "concealed", the library used to say "On the mantelpiece." and stop: now it omits such a line entirely. 43. The treatment of "concealed" possessions of containers is slightly tidied up (though using such is not recommended except in scenery, as it's likely to need some effort to make inventories do the right thing). 44. (Cf. (4) above.) At Gareth Rees' proposal, WriteListFrom now has a policy on what to do if both CONCEAL_BIT and WORKFLAG_BIT are set, causing a clash. In this instance, the "workflag" rule applies at the top level, but not below, and the "conceal" rule applies below but not at the top level. 45. A soupcon of new grammar: "climb over" (just does the Climb action); "thump" and "punch" now equate to "attack"; "present" and "display" to "show"; one can now "stand on" something. 46. It's Christmas, and a new fake action is born. This one is called "ThrownAt" and is analogous to "Receive" for containers: i.e., it runs before rules for the object which something is being thrown at. E.g., before [; ThrownAt: if (noun==dart) { move dart to self; "Triple 20!"; } move noun to location; CDefArt(noun); " bounces incongrously off the board."; ], Note: "after" rules don't apply, as the default behaviour of ThrowAt is to do nothing but rebuke the player. Change in Release 5/7 (941230) ============================== 47. Last and most embarrassing bug fix of 1994: removing a spurious tracing message, "Else clause", left in by accident from earlier debugging. Changes in Release 5/7 (950109) =============================== 48. Minor enhancement to the "tree" debug verb; new "gonear" debug verb, such that "gonear frog", say, takes you to the room the frog is in. 49. The library often needs to print a property value if it's a string, or run it if a routine. There's now a routine to do this: PrintOrRun(object, property, flag); If the (optional) flag is given and non-zero, a new-line is printed after a string (but only if it was a string). The library now makes extensive use of this, tidying up the code somewhat, but the reason for the change was that it was previously doing signed comparisons to work out where addresses lie in memory, which begins to fail when the total game size exceeds about 180K. Two new useful primitives are: UnsignedCompare(x,y) returns 1 if x>y 0 if x=y -1 if x" is now printed via the library messages system, with the (fake) action Prompt. Thus, you might use: Object LibraryMessages "lm" with before [; Prompt: print "^What now? "; rtrue; ]; to change the prompt. Likewise you can adapt it to events, or get rid of the "skipped line on screen each turn" convention. This prompt is only used in ordinary game play, and not at such keyboard inputs as yes/no questions or the RESTART/RESTORE/QUIT game over choice. 70. Subtle change in transparency rules. If you ChangePlayer to some creature, then any animate objects which are (directly or indirectly) holding the creature at the time are made "transparent". This prevents you from finding yourself in darkness for a reason which is now obselete. Changes in Release 5/9 (950217) =============================== 71. "initial" routines for rooms and NewRoom were being called on every Look action, which was wrong behaviour: now they're gone through only before a Look action occurs in a different location from the previous one in which a Look took place. 72. Two messages generated by Enter now differ for trying to get onto an enterable supporter (as opposed to getting into an enterable container). 73. Yet another foolish bug in "objects" fixed: the spurious "None". 74. The parser error NUMBER_PE (generated when a "number" token fails to match) has been demoted in importance. Previously it took precedence over almost every other error, now the reverse is true: so in grammar like "take" * noun -> Take * number -> TakeNumber; if nonsense like "lkjhkjh" is typed, then "You can't see any such thing" is replied in preference to "I didn't understand that number". The assumption behind the change is that when both errors are possible, the former is the "natural" use of the verb, the latter an exceptional one. 75. In some circumstances "location" briefly had the wrong value when running a vehicle's "before" routine for the Go rule to see whether it will allow the player to travel in it. This is now fixed. 76. Small new feature: returning 2 from a vehicle's "before" in such circumstances tells the library to give up and print nothing. 77. Large presentational feature. If a collection of game objects - say, all the edible items in the game - have a common non-zero value of the property "list_together", say 1, they will always appear adjacently in inventories, room descriptions and the like. If, moreover, instead of being a small number the common value is a string such as "foodstuffs" then lists will cite, e.g. three foodstuffs (a scarlet fish, some lemmas and an onion) in running text, or three foodstuffs: a scarlet fish some lemmas an onion in indented lists. (This only happens when two or more are together.) If, moreover, the common value is a routine, e.g. [; if (inventory_stage==1) print "heaps of food, notably "; else print ", which would do you no good"; ], then this will be called twice: once, with "inventory_stage" set to 1, as a preamble to the list of items, and once (with 2) to print any postscript required. It is allowed to change "c_style" (the current list style) without needing to restore the old value and may, by returning 1 from stage 1, signal the list-maker not to print a list at all. The simple example above results in heaps of food, notably a scarlet fish, some lemmas and an onion, which would do you no good Such a routine may want to make use of the variables "parser_one" and "parser_two", which respectively hold the first object in the group and the depth of recursion in the list (this might be needed to keep indentation going properly). Applying x=NextEntry(x,parser_two); moves x on from parser_one to the next item in the group. Another helpful variable is "listing_together", set up to the first object of a group being listed (or to 0 whenever no group is being listed). For further examples, see the little example "List Property", which sorted out the following 24 objects into... You can see a plastic fork, knife and spoon, three hats (a fez, a Panama and a sombrero), the letters X, Y, Z, P, Q and R from a Scrabble set, a defrosting Black Forest gateau, Punch magazine, a recent issue of the Spectator, a die and eight coins (four silver, one bronze and three gold) here. 78. The parser used to overflow occasionally when dealing with a very vague request which matches against far too many items; now it checks the size of the match list before adding to it. (In practice, this only happened when one tried to, e.g., "purloin all" in a game of more than 64 items.) 79. The Search (e.g. "look inside") action sometimes produced mysterious messages when the only contents of the object in question were all "concealed", and similar misfortunes befell some room descriptions. Now mended. 80. A between-routines jump inside the parser has been removed, as it was unnecessary and Mark Howell didn't like the idea. 81. The "wake" grammar is slightly improved, and the WakeOther action (for waking someone else up) is now routed through that person's "life" routine. 82. PlayerTo(...) used only to work for moving a player to a room, but now it can also move a player to something in a room (like a chair). 83. Message for "putting something on a non-supporter" mended. 84. The "In the ... you can see ..." message (printed when you're also in the whatever) is now In or On as appropriate for containers/supporters. 85. "pick up", "look into" and "lie in/on" added to the grammar. Changes in Release 5/10 (950525) ================================= 86. "notify off" no longer perversely replies "Score notification on." 87. Bug in "objects"/"places" when the player's in transformed form, fixed. 88. The parser is now capable of making an inference and then asking a clarifying question, in the same turn: e.g. "unlock" is expanded by the parser into "unlock chest"; "with" is further assumed; then it asks "What do you want to unlock the chest with?" and understands the answer. Likewise it can now infer two successive prepositions, e.g. "next to". 89. PlayerTo(1) (moving the player without a subsequent Look) now calls NewRoom, sorts out floating objects and so forth, as it should. 90. An additive property (one for which inheritance from classes piles up a list of values) can now contain a list in which some items are strings and others routines. Should this occur, then on a PrintOrRun the the entries are executed in sequence - run if routines, printed if strings. A printed string in such a list always has a new-line printed after it; and it never stops the process of execution. In other words, the string "Hello" is equivalent to the routine [; print "Hello^"; ], (which returns false), not to the routine [; "Hello"; ], (which would return true and stop execution). This will seldom be useful but protects the Z-machine stack against certain misfortunes on some machines. 91. The parser once again copes with "put all except the key in the bag". 92. "objects" now tells of "(worn)" objects. (A bug used to prevent this.) 93. Returning 3 from a "before" routine of a vehicle which the player's trying to move inside, says "do nothing, I have moved the player". (Merely returning 2 for "do nothing" may result in the old location being restored.) 94. A subtle bug to do with low strings having mysteriously not-quite-right contents has now been fixed: it was due to a library mistake which Inform 5.4 was unable to detect, but which 5.5 spotted as an error. 95. Small bug in timer/daemon listing debug verb fixed. 96. PlayerTo(somewhere,2) will |Look| as if the player had arrived in the room by walking in as usual (so only a short description appears if the room is one that has been seen before). 97. The parser's "take all" rules work slightly better for actors other than the player, and when the actor is inside something. Changes in Release 5/11 (950619) ================================= 98. *** You have died *** style messages are now in bold-face, except in V3 games. 99. It's now legal to put things into, or take things out of, containers that happen to be worn. I noticed this was illegal when players of Curses complained about the rucksack; and couldn't think of any good reason why it should be illegal! 100. A more appropriate message is produced on attempts to push, pull or turn animate objects. 101. If Initialise() returns 2, then no game banner is printed; thus, it can appear later on instead, as in "Sorcerer". 102. PlayerTo() now works in the (dark room) -> (dark room) case. 103. A bug to do with message passing (which only existed under a rough to-get-Inform-tested copy of 5/10 anyway) has been fixed. 104. A really disastrous bug to do with the parser asking supplementary questions (causing interpreters to behave badly on some machines, e.g. by repeatedly saying "I beg your pardon") has hopefully now been fixed, largely thanks to detective work by Robert Stone and Matthew Russotto. My own interpreter never showed this bad behaviour, and I was barking up the wrong tree in attempts to find it. I now believe it was caused by over-writes in the multiple_object array corrupting the "length" byte of the (immediately following) input buffer "buffer2" used by the parser for disambiguation questions. I have taken three different precautions to prevent this occurring in future. 105. A bug to do with changing the player character and then entering dark locations (when one might spookily bump into one's former self) has been fixed. 106. "ask someone for something" is now automatically translated into "someone, give something to me" (i.e., this ##Order is generated). 107. Multiple-object commands (such as "take all") generate a list of actions, which all make contextual sense at the time when the command is typed. However, a weakness of the parser is that when some of these actions have been processed, the remaining ones may no longer make sense. For instance, if the player has been teleported to the planet Mars halfway through picking up a pile of ten items. The parser now stops the list if the player has either (a) moved location, or (b) fallen into darkness, as a result of earlier actions. 108. When the parser is working on a "creature" token, and the player typed something which is ambiguous but definitely isn't animate, then no question is now asked to resolve this ambiguity (as there's no point). (Such a question used to read slightly oddly.) 109. print (DirectionName) x; will now (under I5.5) print the name of the direction whose door_dir is x. Thus, x==n_to results in "north" being printed. 110. The property "capacity" can now take a routine returning a value, instead of a value. 111. "full score" is now understood as "fullscore". ("full" always was.) ----------------------------------------------------------------------------