Release notes for Inform v3.1 (build 4F59)

This release was made on 21 December 2006, before Inform was open-sourced. At that time versions of Inform were identified by build codes in the form NLNN.

This is part of the historical archive of release notes.

Overview

The main purpose of this build is to publish a redesigned system for phrase and rule declarations, fixing a number of miscellaneous bugs, removing some exceptions and clarifying ambiguities in the existing design. Chapter 18 of the documentation is substantially rewritten as a result, and the Rules page of the index has been redesigned. We believe that the new design is much less ambiguous and, as a result, more fully explained than the old, but the removal of some of these ambiguities does mean that minor changes to some existing source text will be needed. If you have a work in progress nearing its completion, you may need to test that the new rules system does not change its behaviour.

Language

Phrases can be defined by "To ...:" (declaring a new phrase to be used in the definitions of other phrases), by "Definition:" (defining adjectives), by "At ...:" (declaring events to happen at given times) or as rules to go into rulebooks (for instance, "Instead of taking:" goes into the "instead" rulebook). In order to make it easier to tell immediately which of these four forms is intended:
- (i) Rulebook names are now forbidden to begin with the words "To", "At" or "Definition". (So far as we are aware, nobody has ever done this, so this should not cause inconvenience.)
- (ii) Events happening at a fixed time are written "At 3:02 AM:" or similar: events happening at some time not yet determined are now written "At the time when the clock chimes:" rather than, as in previous builds, just "When the clock chimes:". This removes the confusing ambiguity with scene start/end rules (e.g. "When Scene IV begins:") and with "When play begins:", etc.
When Inform adds rules to rulebooks, it sorts them so that more specifically applicable rules (say, "instead of taking the fish") come before vaguer ones ("instead of taking or dropping something"). The method of sorting used was largely unchanged from 3K27 to 4B91, but has now sharpened in the following ways:
- (i) being "in" a room is considered more specific than in a region,
- (ii) and in a subregion more specific than in a super-region,
- (iii) "during..." clauses are now taken account of,
- (iv) "in the presence of..." clauses are now taken account of,
- (v) rules attached to a wider range of actions ("taking or dropping") are less specific than rules attached to a narrower range ("taking"),
- (vi) rules with longer or more complicated "when" conditions are considered more specific than those with shorter,
- (vii) rules applying in a limited range of turns or for a limited number of times are considered more specific than other such rules if the number of turns in which the rule could apply is smaller. Though these changes may change the effect of some complicated source texts now standing, they should only really affect cases where rules were previously considered equally applicable.
When the Index shows the contents of a rulebook, it now uses a graphical notation to show which rules are considered more specific than which others. Hovering the mouse over one of the icons used in this notation causes a "tool tip" to be displayed which explains on what basis the decision was taken.

The special verb "to be listed", used to specify how named rules are listed in rulebooks, is now more flexible. The existing syntax remains:

	The summer breeze rule is listed in the every turn rules.
	The summer breeze rule is listed after the chirping magpie rule
		in the every turn rules.
	The summer breeze rule is listed before the chirping magpie rule
		in the every turn rules.

And the following possibilities are added:

	The summer breeze rule is listed first in the every turn rules.
	The summer breeze rule is listed last in the every turn rules.
	The can't eat unless edible rule is not listed in the check eating rules.
	The can't eat unless edible rule is not listed in any rulebook.
	The refined palate rule is listed instead of the can't eat unless
		edible rule in the check eating rules.

The last three possibilities allow rules to be abolished for the whole game without the need for procedural rules. (A rule abolished in this way still exists, it merely isn't found in rulebooks at the start of play.) This will make extensions which carry out large-scale library changes more efficient.

A "when/while" clause can now be attached to a rule in an object-based rulebook not derived from an activity. (These used to be the only rulebooks whose rules were not allowed a "when" clause, so the change removes an unnecessary exception.)
The synonym "final" for "last", in the context of rulebook placements, has been withdrawn - it was an unnecessary complication. Thus "The last chirping magpie rule:" still works, but "The final chirping magpie rule:" does not.
The new text substitution "[otherwise if ...]" has been added: this can be used in text, between "[if ...]" and "[end if]" substitutions, in just the same way that the phrase "otherwise if ..." can be used between "if ..." and "end if" phrases.
A new rulebook, "does the player mean", has been added to give the parser clues on how to disambiguate commands. (This offers facilities analogous to those provided by ChooseObjects in Inform 6, but applying to whole actions and not to nouns alone.) See the new section 16.16 in the documentation.
File extension for blorbed Glulx-format releases changed from ".zblorb" to ".gblorb". (Apologies: an oversight.)
The horizontal compass directions can no longer automatically be referred to by the word "wall", so that "examine the north wall" no longer generates the action of examining north. This was an old Infocom convention, carried over into Inform 6 for some years, but which causes problems more often than it confers benefits.

Documentation, examples and extensions

Examples

Masochism Deli added to demonstrate "does the player mean..." rules.
Flotation added to demonstrate an object-based rulebook and named outcomes.
Being Peter added to demonstrate an action-based rulebook with named outcomes.
Bronze, 3 AM, MRE, Mr Spruce's Non-Modal Question, Chronic Hinting Syndrome, Fifty Times Fifty Ways, Happy Hour, Lakeside Living, Lemonade, Noisy Cricket, Patient Zero, Y Ask Y modified to show "otherwise if" better.
Barter Barter, Bribery, Bruneseau's Journey, The Dark Ages Revisited, Emma, Fragment of a Greek Tragedy, Mimicry, Minimal Movement, Nickel and Dimed, Stately Gardens, Under Contract, Waning Moon modified to get rid of now-unnecessary procedural rules and use "is not listed..." instead.
Aftershock, Crusoe, Get Axe, The Hang of Thursdays, Panache, Swigmore U, Uptempo, Zqlran Era 8 modified to get rid of now-unnecessary procedural rules and use "is listed instead of..." instead.
Instant Examine and Look modified to get rid of procedural rule in favor of a first rule in the turn sequence rules. Commentary added to explain how the procedural rule might be used and why the first-rule method might be preferable.
No Place Like Home reassigned to the Awarding Points section, as being more relevant there.
Strictly Ballroom corrected for a missing word.
Up and Up modified to use after going rather than before, as this is more reliable.
Beneath the Surface improved to make the chair a supporter.
Witnessed 1 expanded to include new "does the player mean..." rules, improving parsing behavior of the example.
The Night Before added to demonstrate "does the player mean..." rules to lower the parsing significance of body parts belonging to the player compared to those of other people;
Hudsucker Industries substantially updated to simplify logic, provide better parsing behavior using "does the player mean..." rules, and allow the player to refer to sorted letters by property.
Costa Rican Ornithology given slightly more explanation of the topic column, since this appears before the format has been fully introduced.
We, and the two gas diffusion examples, moved to a new location.
We given slightly more commentary to point users at extensions for changing library messages if they want to do so wholesale.
No Relation edited to discuss how Instead of going by... applies to vehicles and other objects.
Morning After edited for a typo in the commentary.
Uptown Girls edited for a typo in the source text.

Bug fixes

Bug fixed by which (on Windows only) accented letters sometimes caused confusion with digits.
Bug fixed by which a rule which applied e.g. "for the third to eighth time" (an explicit range of iterations) would generate code which failed to compile in I6.
Bug fixed in which rules "listed after" or "listed before" might give spurious problems if the rulebook named had a name including the word "with".
Bug fixed whereby the Glulx interpreter was not checked to see if it could provide pictures before being instructed so to do, which produced problems with some text-only Glulx interpreters.

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