Muex.Mutator behaviour (Muex v0.3.3)

Behaviour for mutation operators that transform AST nodes.

Mutators implement specific mutation strategies (e.g., arithmetic operators, boolean operators, literals) and return a list of possible mutations for a given AST.

Each mutator is language-agnostic and works with the raw AST structure provided by the language adapter.

Example

defmodule Muex.Mutator.MyMutator do
  @behaviour Muex.Mutator

  @impl true
  def mutate(ast, _context) do
    # Return list of mutated AST variants
    [mutated_ast_1, mutated_ast_2]
  end

  @impl true
  def name, do: "My Mutator"

  @impl true
  def description, do: "Mutates specific AST patterns"
end

Summary

Types

mutation()

Represents a single mutation with its metadata.

Callbacks

description()

Returns a description of what this mutator does.

mutate(ast, context)

Applies mutations to the given AST.

name()

Returns the name of the mutator.

Functions

walk(ast, mutators, context)

Walks through an AST and applies all registered mutators.

Types

mutation()

@type mutation() :: %{
  ast: term(),
  mutator: module(),
  description: String.t(),
  location: %{file: String.t(), line: non_neg_integer()}
}

Represents a single mutation with its metadata.

Callbacks

description()

@callback description() :: String.t()

Returns a description of what this mutator does.

Returns

String describing the mutation strategy

mutate(ast, context)

@callback mutate(ast :: term(), context :: map()) :: [mutation()]

Applies mutations to the given AST.

Parameters

ast - The AST to mutate
context - Map containing additional context (file path, line number, etc.)

Returns

List of mutation maps, each representing a possible mutation

name()

@callback name() :: String.t()

Returns the name of the mutator.

Returns

String name identifying this mutator

Functions

walk(ast, mutators, context)

@spec walk(ast :: term(), mutators :: [module()], context :: map()) :: [mutation()]

Walks through an AST and applies all registered mutators.

Parameters

ast - The AST to traverse
mutators - List of mutator modules to apply
context - Context map with file information

Returns

List of all possible mutations found in the AST