dmajda

 def check_classes
   # Get list of all subclasses of Scanny::Checks::Check.
   classes = []
   ObjectSpace.each_object(Class) do |klass|
     classes << klass if klass < Scanny::Checks::Check
   end

   # Filter out classes that are a superclass of some other class in the list.
   # This way only "leaf" classes remain.
   classes.reject do |klass|

dmajda

  [
    :REGEXP,
    /^
      \/
        (
          \\                # escape
          (
            [\\"ntrfvaebs]    # one-character escape
            |
            [0-7]{1,3}        # octal number escape

dmajda

{
  function makeNode(type, head, tail) {
    return tail.length > 0
      ? {
          type:  type,
          terms: [head].concat(tail.map(function(t) { return t[1]; }))
        }
      : head;
  }
}

dmajda

/*
 * Task: Parse even numbers in PEG.js (http://pegjs.majda.cz).
 *
 * Solution: Let's parse all numbers and reject odd ones using a semantic
 * predicate -- an arbitrary piece of code that returns true (meaning "continue
 * parsing") or false (meaning "halt parsing").
 *
 * This solution wouldn't work before commit a2af1fe612 because predicates
 * didn't have access to labeled expressions in the grammar as variables
 * (without ugly workarounds). But they have the access now and the solution

dmajda

# Syntax of Ruby is flexible enough to allow writing Lisp-like code.

# We need few helper functions (no Lisp yet):

def list(*args)
  args
end

def car(list)
  list.first