Any one write an AST aware regex engine?

Examples: replace s/(?ast:comment)foo/bar to replace foo with bar but only in comments. Or s/(\w+): (?ast:openparent)(.?)(?ast:closeparen)\s+(?ast:openbracked)(.?)(?ast:closebracket)/function $1($2)\n{\n$3\n}\n/ to convert from

    foo: (args) {
      codeblock
    }

to

    function foo(args) {
      codeblock
    }

etc..?