🕷 software releases

by ryan davis


ParseTree version 2.0.0 has been released!

Published 2007-08-01 @ 10:25

ParseTree is a C extension (using RubyInline) that extracts the parse tree for an entire class or a specific method and returns it as a s-expression (aka sexp) using ruby’s arrays, strings, symbols, and integers.

As an example:

  def conditional1(arg1)
    if arg1 == 0 then
      return 1
    return 0


      [:args, :arg1],
       [:call, [:lvar, :arg1], :==, [:array, [:lit, 0]]],
       [:return, [:lit, 1]],
      [:return, [:lit, 0]]]]]
  • Uses RubyInline, so it just drops in.
  • Includes SexpProcessor and CompositeSexpProcessor.
    • Allows you to write very clean filters.
  • Includes UnifiedRuby, allowing you to automatically rewrite ruby quirks.
  • ParseTree#parse_tree_for_string lets you parse arbitrary strings of ruby.
  • Includes parse_tree_show, which lets you quickly snoop code.
    • echo “1+1” parse_tree_show -f for quick snippet output.
  • Includes parse_tree_abc, which lets you get abc metrics on code.
    • abc metrics = numbers of assignments, branches, and calls.
    • whitespace independent metric for method complexity.
  • Includes parse_tree_deps, which shows you basic class level dependencies.
  • Does not work on the core classes, as they are not ruby (yet).


  • 2 major enhancements:

    • Rewrite methods completely rewritten. Rewriters:
      • are no longer recursive.
      • are no longer required to empty the sexp coming in.
      • are depth first, so rewriter gets passed everything already normalized.
      • keep rewriting until type doesn’t change.
      • are magical goodness.
    • Added UnifiedRuby module to aid others in writing clean SexpProcessors:
      • bmethod/dmethod/fbody unified with defn
      • fcall/vcall unified with call
      • resbody unified with itself (lots of different forms)
  • 5 minor enhancements:

    • Add #modules to Module.
    • Add Sexp::for shortcut for Sexp.from_array ParseTree.translate(…).
    • Add parens for :block nodes as appropriate. May be overzealous.
    • Made add_to_parse_tree global for reuse by other C extensions.
    • Made test_ruby2ruby MUCH more rigorous with circular testing.
  • 6 bug fixes:

    • Added $TESTING = true to pt_testcase.rb. OOPS!
    • Fixed some circular bugs, mostly by hacking them out, wrt operator precidence.
    • Fixed splat arg processing when arg has no name.
    • Fixed trinary operator.
    • Fixed BMETHOD with no arguments.
    • Removed hacky “self.” thing for defs at top level PT use.
  • https://www.zenspider.com/ZSS/Products/ParseTree/