module AST::Sexp
This simple module is very useful in the cases where one needs to define deeply nested ASTs from Ruby code, for example, in tests. It should be used like this:
describe YourLanguage::AST do include Sexp it "should correctly parse expressions" do YourLanguage.parse("1 + 2 * 3").should == s(:add, s(:integer, 1), s(:multiply, s(:integer, 2), s(:integer, 3))) end end
This way the amount of boilerplate code is greatly reduced.
Public Instance Methods
s(type, *children)
click to toggle source
Creates a {Node} with type `type` and children `children`. Note that the resulting node is of the type AST::Node
and not a subclass. This would not pose a problem with comparisons, as {Node#==} ignores metadata.
# File lib/ast/sexp.rb, line 26 def s(type, *children) Node.new(type, children) end