Metastatic.Adapters.Ruby (Metastatic v0.10.4)

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Ruby language adapter for MetaAST transformations.

Bridges between Ruby AST (M1) and MetaAST (M2), enabling cross-language code analysis and transformation for Ruby source code.

Ruby AST Structure (M1)

Ruby uses the parser gem which represents AST as nodes with:

  • type - Symbol representing the syntactic construct
  • children - List of child nodes or values
  • location - Source location information

Examples

# Variable assignment
%{type: "lvasgn", children: ["x", %{type: "int", children: [42]}]}

# Method call
%{type: "send", children: [receiver, :method_name, args...]}

# Binary operation
%{type: "send", children: [left, :+, right]}

M1 ↔ M2 Transformations

This adapter performs bidirectional transformations between Ruby AST (M1) and MetaAST (M2):

Literals

# M1 → M2
%{type: "int", children: [42]}     → {:literal, :integer, 42}
%{type: "float", children: [3.14]} → {:literal, :float, 3.14}
%{type: "str", children: ["hello"]} → {:literal, :string, "hello"}
%{type: "true"}                     → {:literal, :boolean, true}
%{type: "nil"}                      → {:literal, :null, nil}
%{type: "sym", children: [:foo]}    → {:literal, :symbol, :foo}

Variables

%{type: "lvar", children: [:x]}     → {:variable, "x"}
%{type: "ivar", children: [:@x]}    → {:variable, "@x"}

Binary Operations

# x + 5
%{type: "send", children: [x_node, :+, five_node]} → {:binary_op, :arithmetic, :+, left, right}

Round-Trip Fidelity

The adapter achieves >95% round-trip fidelity for M2.1 (Core) constructs. Metadata preserves information like:

  • Line numbers and columns
  • Variable scopes (local, instance, class, global)
  • Original syntax variants

Usage

# Parse Ruby source
{:ok, ast} = Metastatic.Adapters.Ruby.parse("x = 42")

# Transform to MetaAST
{:ok, meta_ast, metadata} = Metastatic.Adapters.Ruby.to_meta(ast)

# Transform back to Ruby AST
{:ok, ast2} = Metastatic.Adapters.Ruby.from_meta(meta_ast, metadata)

# Unparse to source
{:ok, source} = Metastatic.Adapters.Ruby.unparse(ast2)