Enum ControlFlow

pub enum ControlFlow {
    Match {
        source: BindingId,
        arms: Vec<MatchArm>,
    },
    Equal {
        a: BindingId,
        b: BindingId,
        body: Block,
    },
    Loop {
        result: BindingId,
        body: Block,
    },
    Return {
        pos: Pos,
        result: BindingId,
    },
}

What kind of control-flow structure do we need to emit here?

Variants

Match

Test a binding site against one or more mutually-exclusive patterns and branch to the appropriate block if a pattern matches.

Fields

source: BindingId

Which binding site are we examining at this point?

arms: Vec<MatchArm>

What patterns do we care about?

Equal

Test whether two binding sites have values which are equal when evaluated on the current input.

Fields

a: BindingId

One binding site.

b: BindingId

The other binding site. To ensure we always generate the same code given the same set of ISLE rules, b should be strictly greater than a.

body: Block

If the test succeeds, evaluate this block.

Loop

Evaluate a block once with each value of the given binding site.

Fields

result: BindingId

A binding site of type Binding::Iterator. Its source binding site must be a multi-extractor or multi-constructor call.

body: Block

What to evaluate with each binding.

Return

Return a result from the right-hand side of a rule. If we’re building a multi-constructor then this doesn’t actually return, but adds to a list of results instead. Otherwise this return stops evaluation before any later steps.

Fields

pos: Pos

Where was the rule defined that had this right-hand side?

result: BindingId

What is the result expression which should be returned if this rule matched?