require 'polyglot'
require 'treetop'
require 'awesome_print'
require File.join(File.dirname(__FILE__), 'scope')

Treetop.load File.join(File.dirname(__FILE__), 'expressive_grammar.treetop')

module Expressive
  def self.run(source_code, scope = TopLevel.new )
    program = parse(source_code)
    program.eval(scope)
  end

  def self.parse(expressions)
    @parser ||= ::ExpressiveParser.new
    @parser.parse(expressions)
  end
end


module Boolean 
  def eval(scope)
   'true' == text_value 
  end
end

module IntegerValue 
  def eval(scope) 
    text_value.to_i
  end
end

module FloatValue 
  def eval(scope) 
    text_value.to_f 
  end
end

class Program < Treetop::Runtime::SyntaxNode
  def eval(scope)
    elements.map {|e| 
      e.eval(scope)
    }.last
  end
end

class List < Treetop::Runtime::SyntaxNode
  def statements
    elements[1].elements.map {|e| e.data }
  end

  def eval(scope)
    function = statements.first.eval(scope)
    function.call(scope, statements[1..-1])
  end
end

class Statement < Treetop::Runtime::SyntaxNode
  def data
    elements[1]
  end

  def eval(scope)
    data.eval(scope)
  end
end

# class SetNode < Treetop::Runtime::SyntaxNode
#   def pieces
#     [ :set, fieldname.text_value, value.text_value ]
#   end
# end

class Identifier < Treetop::Runtime::SyntaxNode
  def eval(scope)
    scope[text_value]
  end
end

class Function
  def initialize(&block)
    @block = block
  end

  def call(scope, statements)
    parameters = statements.map {|c| c.eval(scope)} 
    @block.call(*parameters)
  end
end

class Syntax < Function
  def call(scope, statements)
    @block.call(scope, statements)
  end
end