Typle.Inference.Pattern (Typle v0.3.1)

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Extracts variable type bindings from pattern matches.

Given a pattern AST and the type of the expression being matched, narrows the type to the subset compatible with the pattern structure, decomposes composite types (tuples, lists, maps) into their element types, and propagates those types to bound variables.

Also records the inferred type at each variable's source position so that Typle.type_at/3 can report pattern-variable types.

Summary

Types

bindings()
positions()

Functions

infer(pattern, matched_type)

Infers variable types from a pattern, given the type of the matched expression.

Types

bindings()

@type bindings() :: %{required(atom()) => Typle.Type.t()}

positions()

@type positions() :: %{
  required({non_neg_integer(), non_neg_integer()}) =>
    {Typle.Type.t(), String.t() | nil}
}

Functions

infer(pattern, matched_type)

@spec infer(Macro.t(), Typle.Type.t()) :: {bindings(), positions()}

Infers variable types from a pattern, given the type of the matched expression.

Returns {bindings, positions} where bindings maps variable names to their inferred types and positions maps {line, col} to the type at that source location.