module Lox module Expr def self.expr(name, *children) klass = Struct.new(name.to_s, *children) do def accept(visitor) klass = self.class.to_s.split("::").last.downcase visitor.send("visit_#{klass}", self) end end const_set(name, klass) end expr :Assign, :name, :value expr :Binary, :left, :op, :right expr :Call, :callee, :paren, :args expr :Get, :object, :name expr :Grouping, :expr expr :Literal, :value expr :Logical, :left, :op, :right expr :Set, :object, :name, :value expr :Super, :keyword, :method expr :This, :keyword expr :Unary, :op, :right expr :Variable, :name end end