lib/match-plan.x

Lowering Match patterns to prepared plans.

Runtime-internal callables

These callables connect runtime translation units. They are documented for source readers but are not supported as user API.

MatchPlan

MatchPlan.free

void MatchPlan.free(MatchPlan plan)

Releases resources owned by plan. A null plan is ignored; the plan, layout, program, and all aliases to them are invalid afterward. Borrowed pattern constants are not released.

Source: lib/match-plan.x:78

MatchPlan.prepare

MatchPlan MatchPlan.prepare(Var pattern)

Compiles pattern into a reusable immutable MatchPlan. The caller owns the returned plan in the active Scope. Preparation records MACHINE_PREPARED, MACHINE_MALFORMED, or MACHINE_INELIGIBLE in the plan and raises for none of them; only a prepared plan has a program. reason is a borrowed static category string. The plan borrows pattern constants, which must outlive it.

Raises: <alloc-fail> while analyzing, lowering, or freezing.

Source: lib/match-plan.x:48

Design notes

A MatchPlan is the prepared form of one pattern: its capture layout and a program in the wordcode of machine.x. A plan owns both and borrows the canonical values in its pattern. Preparation records why a pattern has no program and raises for none of them; match.x runs the plan.