glisp / expand

expand

Functions

expand()

expand(ast, env): AST

One step of macro expansion. If ast is a call to a Glisp closure with a body, substitute the closure’s parameters with the call’s argument ASTs throughout the body and return the resulting AST. Otherwise return ast unchanged.

Reserved special forms (?, |>, def, undef, overload) are not expanded: expanding them would lose their custom dispatch semantics. For repeated expansion until a fixed point, see expandLadder and expandAll.

Parameters

Parameter	Type
`ast`	`AST`
`env`	`Env`

Returns

AST

expandAll()

expandAll(ast, env, options?): AST

Defined in: expand.ts:72

Convenience: same as expandLadder(ast, env).at(-1) — only the fully-expanded fixed point.

Parameters

Parameter	Type
`ast`	`AST`
`env`	`Env`
`options?`	{ `maxSteps?`: `number`; }
`options.maxSteps?`	`number`

Returns

AST

expandLadder()

expandLadder(ast, env, options?): readonly AST[]

Defined in: expand.ts:51

Iterate expand from ast until a fixed point is reached. Returns the sequence of intermediate ASTs (the “abstraction ladder” per docs/spec/eval.md), starting with the input. The last entry is always the fixed point — calling expand again yields the same node.

maxSteps guards against pathologically slow but non-cyclic expansion. Defaults to 64.

Parameters

Parameter	Type
`ast`	`AST`
`env`	`Env`
`options?`	{ `maxSteps?`: `number`; }
`options.maxSteps?`	`number`

Returns

readonly AST[]