Line Templates

Lines in brink can be plain strings or templates with interpolation slots and plural/gender selects.

LineContent

enum LineContent {
    Plain(String),
    Template(LineTemplate),
}

struct LineTemplate {
    parts: Vec<LinePart>,
}

Template parts

enum LinePart {
    Literal(String),
    Slot(u8),
    Select {
        slot: u8,
        variants: Vec<(SelectKey, String)>,
        default: String,
    },
}

• Literal — static text fragments between dynamic parts.
• Slot — runtime value interpolation. The u8 is an index into the evaluation stack snapshot captured when the line is emitted. For example, "You have {0} gold" becomes [Literal("You have "), Slot(0), Literal(" gold")].
• Select — plural/keyword branching. Selects a variant string based on the runtime value at the given slot, using a SelectKey to match. Falls back to default if no variant matches.

Select keys

enum SelectKey {
    Cardinal(PluralCategory),
    Ordinal(PluralCategory),
    Exact(i32),
    Keyword(String),
}

• Cardinal — CLDR cardinal plural categories (zero, one, two, few, many, other). Used for “1 apple” vs “2 apples”.
• Ordinal — CLDR ordinal categories. Used for “1st”, “2nd”, “3rd”.
• Exact — matches a specific integer value. Useful for special-casing “0 items” or “exactly 1”.
• Keyword — matches a named string key. Used for gender or custom grammatical categories.

Line tables

Line tables are stored per-scope (one per knot/stitch/root) in the .inkb format. Each scope has a sequence of LineEntry values referenced by index from EmitLine opcodes. The EvalLine opcode handles templates with interpolation, evaluating slots from the current stack state.

Choice text decomposition

Ink choices have up to three text parts: start content (before [), choice-only content (inside []), and output-only content (after ]). The compiler decomposes each choice into two independent lines:

• Display line = start + choice-only (what the player sees in the choice list)
• Output line = start + output-only (what appears in the narrative after selection)

This decomposition allows translators to localize each line independently — the target language can use completely different grammatical constructions for the prompt and the narrative output.