meta.rb

require "rubygems"
require "johnson"

require "./visitor.rb"

js =<<-END
  function top() {
    "top docstring", { command: true }
    doSomething();
  };
  
  function justADocstring() {
    "justADocstring docstring"
    doSomething();
  }
  
  function noMeta() {
    doSomething();
  };

  Namespace = {
    nested: function() {
      "nested docstring", { command: true }
      doSomething();
    },
    
    Doubly: {
      nested: function() {
        "doubly nested docstring", { command: true }
        doSomething();
      }
    }
  };
  
  var NamespaceWithVar = {
    nested: function() {
      "nested with var docstring", { command: true }
      doSomething();
    }
  };
END

ast = Johnson.parse(js);

visitor = MetaVisitor.new("inlineText") do |data|
  puts data.inspect
end

ast.accept(visitor)

visitor.rb

class Array
  def poke(item, &block)
    push(item)
    yield(item)
    pop
  end
end

class MetaVisitor < Johnson::Visitors::EnumeratingVisitor
  class Data
    attr_reader :name, :file, :line, :column, :docs, :extras
    
    def initialize(name, file, line, column, docs, extras={})
      @name = name
      @file = file
      @line = line
      @column = column
      @docs = docs
      @extras = extras
    end
  end

  def initialize(file, &block)
    @file      = file
    @block     = lambda {} # FIXME: refactoring Johnson to make this better
    @realblock = block
    @namespace = []
  end

  def visit_Function(o)
    name = (@namespace + [o.name]).compact.join(".")
    docs = extract_docs(o)
    extras = extract_extras(o)
    
    if docs
      data = Data.new(name, @file, o.line, o.column, docs, extras)
      @realblock[data]
    end
  end

  %w(OpEqual AssignExpr Property).each do |type|
    define_method(:"visit_#{type}") do |o|
      @namespace.poke(o.left.value) { super }
    end
  end
  
  def extract_extras(function)
    extras = {}

    if Johnson::Nodes::Comma === comma = function.body.value.first
      if Johnson::Nodes::ObjectLiteral === object = comma.value.last
        object.value.each do |property|
          extras[property.left.value.to_sym] = property.right.value
        end
      end
    end
    
    extras
  end
  
  def extract_docs(function)
    case node = function.body.value.first
    when Johnson::Nodes::String
      node.value
    when Johnson::Nodes::Comma
      node.value.first.value
    end
  end
end