define phrasebook, use phrasebook

A phrasebook groups phrase definitions into one named collection, optionally gated by a while predicate. It carries no fixed meaning of its own. It is simply a way to differentiate text by world state, and whatever the predicate selects for is up to you: a narrative voice, a mood, a chapter, or a location. Whichever declared book's while predicate holds at render time supplies the text, matched first in declaration order, per key. A predicate-less book is the default phrasebook. It is active whenever no earlier book claims the key, and it is the feature at its simplest: one named book with no predicates, used only to group entries.

define phrasebook midnight-book while midnight
  vane-mood, first-time:
    The vane swings hard north, as if the night had opinions.
  or
    The vane holds north. Of course it does.
end phrasebook

define phrasebook evening-book
  vane-mood, first-time:
    The vane noses the evening breeze, unhurried.
  or
    The vane sits easy in the last of the light.

  vane-quiet:
    The vane keeps its own counsel.
end phrasebook

Entries are ordinary phrase definitions. Each takes the form <key>[, strategy]: with or variants, and all five strategies apply, verbatim included. The consuming side is unchanged: you write phrase vane-mood in a clause body, or a {vane-mood} marker in prose. At midnight the first book wins vane-mood, and at any other time the default book supplies it. The default book covers vane-quiet alone, so vane-quiet renders the same in every state. Fallthrough is per key, never per book.

The compiler load-checks each of the following rules.

• Story text always wins. A story-wide define phrase vane-mood (outside any book) beats every book, in every state; a per-entity phrase vane-mood: beats even that. Swapping books never changes text you wrote at those levels.
• Story keys only. A book entry key is a single kebab-case word in the story's own phrase namespace. A dotted platform message ID raises analysis.phrasebook-dotted-key. To override a platform message, use a story-level override message <alias> block (ADR-255).
• The book's while is the only gate. An entry-level while raises analysis.phrasebook-entry-gate. Split the entry into a second book instead.
• Counters are per book. first-time/cycling/sticky state belongs to the entry: two books' first-time texts for the same key each fire their own "first", and both survive save/restore.
• The active book is chosen at render. The choice happens when the turn's text renders, against the turn's final state. A turn that flips a predicate renders its whole output from the newly active book.

Two companion forms live outside the define phrasebook block, in the story header and in imported files.

story "The Folly at Fernhill" by "The Sharpee Project"
  use phrasebook candlewick-gothic while the player holds the locket
  use phrasebook plain-country

import "voices/winter"

use phrasebook <name> [while <condition>] in the story header activates a packaged phrasebook by name and binds the predicate at the use site. You may write it any number of times, and an unknown name raises analysis.unknown-phrasebook. import "voices/winter" at the top level splices in a file of your own define phrasebook blocks. The file on disk is voices/winter.chord, and its books take their arbitration position at the import line. A phrasebook file is just one kind of fragment, because import pulls in any multi-file story source, not only phrasebook blocks. Header use lines and spliced body blocks arbitrate together, in file order.