AbstractSyntaxTree provides methods to parse Ruby code into abstract syntax trees. The nodes in the tree are instances of RubyVM::AbstractSyntaxTree::Node.

This module is MRI specific as it exposes implementation details of the MRI abstract syntax tree.

This module is experimental and its API is not stable, therefore it might change without notice. As examples, the order of children nodes is not guaranteed, the number of children nodes might change, there is no way to access children nodes by name, etc.

If you are looking for a stable API or an API working under multiple Ruby implementations, consider using the parser gem or Ripper. If you would like to make RubyVM::AbstractSyntaxTree stable, please join the discussion at bugs.ruby-lang.org/issues/14844.

Class Methods

Returns AST nodes of the given proc or method.

RubyVM::AbstractSyntaxTree.of(proc {1 + 2})
# => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:35-1:42>

def hello
  puts "hello, world"
end

RubyVM::AbstractSyntaxTree.of(method(:hello))
# => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-3:3>

Parses the given string into an abstract syntax tree, returning the root node of that tree.

SyntaxError is raised if the given string is invalid syntax.

RubyVM::AbstractSyntaxTree.parse("x = 1 + 2")
# => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-1:9>

Reads the file from pathname, then parses it like ::parse, returning the root node of the abstract syntax tree.

SyntaxError is raised if pathname’s contents are not valid Ruby syntax.

RubyVM::AbstractSyntaxTree.parse_file("my-app/app.rb")
# => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-31:3>