inform7/resources/Changes/Change Logs/4X60.txt

4X60 (23 August 2007)

This build adds 19 new examples and modernises a dozen others, and presents
a new volume of built-in documentation: the Inform Recipe Book. It also
provides new features for variable text, improves and extends table-handling,
allows Glulx-format games to read and write files and communicate with
external programs, and allows extensions to create more readable and
useful documentation.

(Windows only) Added support for Glulx mouse events and hyperlinks to the
	game tab.
(Windows only) The justification style hint is now supported when running
	a Glulx game in the game tab. As a result, games using Emily Short's
	"Glulx Image Centering" will now work when run within the application.

A new manual, The Inform Recipe Book, has been added to the application. It
	sits alongside the previous manual (Writing with Inform) and presents
	the examples thematically, with connecting advice and comparisons of
	techniques to achieve a wide range of IF effects. This should make the
	(now 357) examples much easier to browse and to borrow from.
The "[one of]" text substitution previously provided by Jon Ingold's
	extension "Text Variations", which built on code by Andrew Plotkin and
	Roger Firth, has now been adopted into Inform's core language. Examples
	of its use include:
		say "You flip the coin. [one of]Heads[or]Tails[purely at random].";
		say "[one of]The phone rings[or]The phone rings a second time[or]The
			phone rings again[stopping].";
		say "You turn the light switch [one of]off[or]on[cycling]. Nothing
			happens.";
		say "The newspaper headline is: [one of]War Casualties
			[or]Terrorists[or]Banks[sticky random] [one of]Continue To Expand
			[or]Lose Out[sticky random].";
		say "The light changes randomly again; now it's [one of]green
			[or]amber[or]red[at random].";
		say "Zorro strides by, [one of]looking purposeful[or]grim-faced[or]deep
			in thought[or]suppressing a yawn[or]scratching his ribs[or]trying
			to conceal that he has cut himself shaving[as decreasingly
			likely outcomes].";
		say "You dip into the chapter on [one of]fish[or]mammals[or]birds
			[or]reptiles such as the black salamander[in random order]."
	See the new section 5.6 in the documentation: note that "[as decreasingly
	likely outcomes]" and "[in random order]" are new options, the former
	using a tapering probability distribution, the latter a random permutation.
>--> It should be noted that the new implementation of this substitution is
	completely different to the one provided by the extension. The previous
	method involved printing all the text to a buffer array, then hash-coding
	it and taking choices based on this hash, which meant that the same
	sequence of choices occurring twice in the same text would be effectively
	the same (because of having the same hash code); thus
		"This is [one of]A[or]B[at random] versus [one of]A[or]B[at random]."
	could never print "This is A versus A." or "This is B versus B." The new
	implementation treats each "[one of]..." individually. To get around this,
	define
		To say A-or-B: say "[one of]A[or]B[at random]".
	and then change the text to
		"This is [A-or-B] versus [A-or-B]."
	Furthermore, there is no buffer array, no hash code, and it is no longer
	possible to extract state information by deliberately printing the text
	with an incomplete "[one of]" construction. (To quote the Text Variations
	documentation: "a terrible way to solve that kind of problem", so we don't
	feel too bad about withdrawing it.) Thus the phrases "the index of the
	last buffer" and "the index of the buffer" no longer exist.
	In any case, the new implementation polices the use of the construction
	so that leaving it incomplete is no longer possible. "[one of]" must be
	matched by one of its possible conclusions "[purely at random]",
	"[stopping]", ..., or problem messages will be generated; similarly,
	"[or]" can only legally be used inside the construction. On the other
	hand, the new implementation does allow the construction to be nested, both
	explicitly in a single text and also implicitly (where a text substitution
	inside one of the options itself does something which also involves a
	"[one of]"), where the old implementation would silently have failed.
	As an explicit example:
		"[one of]A palace on the [one of]Nile[or]Euphrates[purely at random]
		delta[or]A hovel by the [one of]Tigris[or]Rhine[purely at random]
		river[purely at random]."
	In practice, if a work in progress used "Text Variations" and did not
	try to use "the index of the last buffer" then there is a good chance
	that simply deleting the line
		Include Text Variations by Jon Ingold.
	will be the only change required.
	We thank Jon Ingold and his collaborators for donating their design. The
	extension "Text Variations" will continue to be available from the website
	for the time being, but marked as no longer needed or compatible with
	builds from here onwards. We suggest that users uninstall it once they
	are sure that any works in progress continue to work without.
	This change implements proposal (6.20) from the January 2007 consultation
	document.
The run-time code for handling tables has been rewritten to improve its
	reliability and efficiency. A number of minor bugs have been fixed in
	the process, notably a failure to sort correctly on tables which contain
	mixed blank and non-blank rows, and a rarely occurring problem to do with
	storing the number 32739 in table entries under the Z-machine.
Table sorting is now carried out using a hybrid algorithm: insertion sort
	from 1 to 11 rows, and in-place mergesort for 12 rows and up. This is
	much faster on even medium-sized tables (e.g. about ten times faster on
	tables of 200 rows), and is also stable in all cases: that is, if
	two rows have the same value in the X column of a table, and that
	table is then sorted (forwards or backwards) on the X column, then
	they will stay the same side as each other. As a consequence, all sorts
	are idempotent, that is, performing the same sort operation twice always
	results in the second operation making no changes at all. (The previous
	algorithm was idempotent but, owing to a bug, not in all cases stable.)
	Insertion/in-place mergesort was chosen because we needed stability,
	O(n log n) average running time (together with good performance
	on nearly-sorted tables, which are the commonest usage cases in
	actual Inform source text), O(1) storage overhead (the Z-machine is
	extremely short of table space), and reasonably predictable stack usage.
Projects compiled for Glulx rather than the Z-machine now have the ability
	to make use of external files. Like sound effects and figures, these
	are declared and given names before use:
		The File of Glaciers is called "ice".
	This creates a new named constant "File of Glaciers" (whose kind of value
	is "external-file") for use in file contexts. (The prefix "binary file"
	rather than "file" can be used to make the file binary in the Glk sense,
	but the default is to use text files for all purposes.) Each file is
	considered to be owned by some project, identified by its IFID. By
	default, a newly declared file is owned by its own project, but we can
	also specify that we want to use somebody else's file, either explicitly
	or vaguely:
		The file of Spectral Sequences (owned by project
			"4122DDA8-A153-46BC-8F57-42220F9D8795") is called "adams".
		The file of Boundaries (owned by another project) is called "milnor".
	We can write or append to a file owned by anyone, but can only read a
	file whose ownership matches this description.
	External files are indexed in the Contents index, alongside figures and
	sound effects.
	Files sometimes exist, and sometimes do not: they are sometimes complete,
	sometimes only partly written. (For a file shared between two games
	running simultaneously, one might try to read a file the other is still
	in the middle of writing.) We can test this with:
		if the file of Invariants exists...
		if ready to read the file of Invariants...
	A file cannot be ready if it does not exist, so the latter is a stronger
	condition.
Tables can be saved to external files, and loaded them back in again, during
	play: all file-handling is done automatically. The user only needs to use
	the phrases:
		read the File of Glaciers into the Table of Antarctic Features;
		write the File of Glaciers from the Table of Antarctic Features;
	Blank entries are preserved; it is legal to write a small file into a
	large table, and if so, all unwritten entries are blanked; a run-time
	problem is shown if the file contains more rows or columns than will
	fit into the table which it is being loaded into; similarly, a run-time
	problem is shown on trying to write a table which contains data not
	safely exchangeable with other story files (or other compilations of
	itself).
Text can also be saved to a file, and again all file-handling is automatic:
		write "Jackdaws love my big sphinx of quartz." to the file of
			Abecedary Wisdom;
		append "Jinxed wizards pluck ivy from the big quilt." to the file of
			Abecedary Wisdom;
	The quoted text can, of course, contain substitutions, so can be
	long and complex if need be. On an append, the file is created if it does
	not already exist.
Text from a file is printed back with the text substitution:
		"[text of the File of Abecedary Wisdom]"
	To copy one file to another, for instance,
		write "[text of the file of Abecedary Wisdom]" to the file of
			Secondary Wisdom;
>--> The implications to do with lockability have been improved:
		A locked thing is usually lockable.
		A locked container is usually closed.
		A locked door is usually closed.
		A lockable container is usually openable.
		A lockable door is usually openable.
	Thus writing "The ballot box is a locked container." will now deduce that
	the box is probably lockable, closed but openable. These are only guesses
	by Inform, and can be overridden by giving explicit instructions to the
	contrary: "The ballot box is a locked unopenable container."
Definitions of adjectives, which previously had to refer to their subjects
	only by the pronoun "it" (or in some cases "his", "her", etc.), can now
	make callings. For instance:
		Definition: a direction (called thataway) is viable if the
			room thataway from the location is a room.
	is a good deal easier to read than
		Definition: a direction is viable if the room it from the location
			is a room.
	which was previously the only way to write this. Only a single calling
	can be made, and it must refer to the specific object to which the
	definition applies.
A new rule in the Standard Rules, the "can only take things rule", prevents
	the taking of objects which are not things - for instance, rooms or
	directions. (Such an action can never normally be generated by the
	grammar for typed commands, but if Understand sentences are written
	to open the possibility then the player will see ugly "programming error"
	messages: the new rule prints a more suitable reply.)
Extension documentation can now request "paste into the source text" icons
	like those found in the main documentation and its examples. If an
	indented paragraph of quoted source text begins with an asterisk and
	then a colon, like so...
		*: A dog is a kind of animal.
	...then the asterisk-and-colon are replaced in the final documentation
	by a paste icon: clicking this will insert the copy which follows into
	the source text. The text to be pasted is considered to begin after the
	colon, and to continue until the next unindented text, i.e., it can
	run for many quoted paragraphs, but as soon as the quotation is broken
	the paste extent will end. Any tables within the quoted range should
	be safely rendered with tabs in between the columns.
Large extensions which need to include a large amount of documentation
	can now subdivide it using headings and/or subheadings, like so:
		Chapter: Pesky Meddling Kids
		Section: Dog Food
	A suitable table of contents with navigation links will be automatically
	added to the extension documentation, if so.
The Extensions chapter of the documentation has, appropriately enough, been
	extended: it now opens up a limited number of previously restricted
	syntaxes to public use. These will only be useful to experienced Inform 6
	programmers.
Fixed a further namespace clash: a "let" name can now coincide with the
	column name of a table. (This was preventing John Clemens's extension
	"Scheduled Activities" from working in recent builds.)
Extensions:
	"Basic Screen Effects" very slightly updated so that the documentation
		is clearer about the lack of colored letters in Glulx, and suggests
		that the author turn to Glulx Text Effects for these capabilities
		instead; also given a new example to demonstrate forcing the player
		to type what we want him to type (since this is becoming something
		of a frequently-asked question); chapter and section headings and
		paste-able examples added.
	"Basic Help Menu", "Glulx Text Effects", "Locksmith", "Menus",
		"Punctuation Removal" tagged so that the example can be pasted.
	"Complex Listing", "Plurality" tagged and given chapter and section
		headings.
Examples:
	"Radio Daze" example from Jon Ingold's Text Variations extension brought
		into the main documentation.
	"Camp Bethel" added to demonstrate several other common applications of
		text alternatives.
	"Chanel version 1" added to demonstrate paired "[i]...[/i]" and
		"[b]...[/b]" italic and boldface tags, similar to HTML's.
	"Blink" added to demonstrate creating one's own text variations keyed
		to values, using the special terminology explained in the Extensions
		chapter.
	"Uncommon Ground" added to demonstrate creating one's own text variations
		keyed to the identity of the player character.
	"Labyrinth of Ghosts" added to demonstrate recording the deaths of all
		previous players of the story file by storing them in a file.
	"Alien Invasion Part 23" added to demonstrate saving preference files
		from one game in a series for use in the next episode.
	"Flathead News Network" added to demonstrate communicating with a simple
		Unix script running in the background, in order to provide live news
		headlines (drawn from RSS feeds) inside a story file.
	"Ferragamo Again", "Straw Boater" slightly cleaned up to be better filed
		in the Recipe Book.
	"Cinco" edited to fix a particularly bone-headed bug that vitiated the
		whole point of the example.
	"When?" adjusted to slightly improve the way the example is described.
	"Modern Conveniences" added to demonstrate standard kitchen and bathroom
		appliances.
	"Do Pass Go" added to demonstrate a pair of dice.
	"Mirror, Mirror" added to demonstrate remembering the current room
		description by preserving it in an external file.
	"The Unbuttoned Elevator Affair" added as an example of a simpler lift
		than the elaborate one in "Dubai".
	"Further Reasons Why All Poets Are Liars" added as an example of using
		action variables for an action which moves a box around internal
		positions inside a location; a much thinner version of this example,
		"A pushable box", has been removed.
	"M. Melmoth's Duel" added, similarly to replace "Tinted wallpaper".
	"The Second Oldest Problem" added to demonstrate using action variables
		to make the going action react to moving between dark rooms.
	"Saint Eligius" added to demonstrate an additional comment added to a
		room description when the player first enters.
	"Baritone, Bass" added to demonstrate defining the character at the
		start of play.
	"Bic" added to demonstrate testing whether any defined objects are missing
		description properties.
	"Meet Market" added to demonstrate relations involving multiple values.
	"Depth" rewritten to improve the simulated geometry used to test whether
		an item could fit inside a container.
	"Patient Zero," "Today Tomorrow," "Reporting rules for other characters'
		behavior," "Uptown Girls", "Full Moon" edited to take advantage of
		new text variation features.
	"Belfry", "Bikini Atoll", "Dearth and the Maiden", "Hayes Code",
		"Lies", "Safety", "Undertomb" and "Weathering" all made into formal
		numbered examples rather than, as in previous builds, appearing in
		the running text of the manual.
Bug fixed (or, if you prefer, feature added) whereby sentences providing
	alternative names for times of day, like:
		Understand "lunch time" as 11:30 am.
	...now work as might be expected.
Bug fixed whereby Understand ... as a person would fail with I6 errors.
	(Apologies for this: an oversight in 4W37's abolition of the
	player-character kind, which had the same flaw, but nobody noticed
	because it was so little used.)
Bug fixed whereby "if S is not happening", for S a scene, would incorrectly
	think that a completed once-only scene was still happening.
Bug fixed whereby implications would in some cases be ignored in circumstances
	which it would be tiresome to write out, but to do with multiple things
	being simultaneously present, some qualifying and some not.
Bug fixed whereby using I7 to rerelease an existing I6 story file in
	blorbed format with bibliographic data would fail because of the lack
	of a room (needed to initialise certain room variables).
Bug fixed whereby a few either/or properties could not be changed in play
	without spurious run-time problems being produced. (In particular,
	"now X is transparent" or "now X is opaque" caused problems.)
Bug fixed whereby declaring that the player is a person who happens to be
	initially somewhere other than in the earliest-created room, or outside
	the map altogether, would cause programming errors or other strange
	phenomena at run-time.
Bug fixed where a player attempting to UNLOCK a door which is "locked" but
	which, unbeknownst to the player, has no matching key, would cause a
	run-time problem complaining about the lack of a "matching key" property.
Problem message added for trying to use "[something related by...]" to
	understand something which can have no relations.