module Opal::Nodes::Helpers

def current_indent 

def current_indent
  compiler.parser_indent
end

def empty_line 

def empty_line
  push "\n"
end

def indent(&block) 

def indent(&block)
  compiler.indent(&block)
end

def js_falsy(sexp) 

def js_falsy(sexp)
  if sexp.type == :call
    mid = sexp[2]
    if mid == :block_given?
      scope.uses_block!
      return "#{scope.block_name} === nil"
    end
  end
  with_temp do |tmp|
    [fragment("((#{tmp} = "), expr(sexp), fragment(") === nil || (#{tmp}._isBoolean && #{tmp} == false))")]
  end
end

def js_truthy(sexp) 

def js_truthy(sexp)
  if optimize = js_truthy_optimize(sexp)
    return optimize
  end
  with_temp do |tmp|
    [fragment("((#{tmp} = "), expr(sexp), fragment(") !== nil && (!#{tmp}._isBoolean || #{tmp} == true))")]
  end
end

def js_truthy_optimize(sexp) 

def js_truthy_optimize(sexp)
  if sexp.type == :call
    mid = sexp[2]
    if mid == :block_given?
      expr(sexp)
    elsif Compiler::COMPARE.include? mid.to_s
      expr(sexp)
    elsif mid == :"=="
      expr(sexp)
    end
  elsif [:lvar, :self].include? sexp.type
    [expr(sexp.dup), fragment(" !== false && "), expr(sexp.dup), fragment(" !== nil")]
  end
end

def line(*strs) 

def line(*strs)
  push "\n#{current_indent}"
  push(*strs)
end

def lvar_to_js(var)

varibales
are valid in javascript. A $ suffix is added to non-valid names.
Converts a ruby lvar/arg name to a js identifier. Not all ruby names 
def lvar_to_js(var)
  var = "#{var}$" unless valid_name? var.to_s
  var.to_sym
end

def mid_to_jsid(mid)

wrapped in brackets to use reference notation calling.
have a '.' prefix (for dot-calling), otherwise it will be
a '$', and if the name is a valid javascript identifier, it will
a method/function call. All ruby method names get prefixed with
Converts a ruby method name into its javascript equivalent for 
def mid_to_jsid(mid)
  if /\=|\+|\-|\*|\/|\!|\?|\<|\>|\&|\||\^|\%|\~|\[/ =~ mid.to_s
    "['$#{mid}']"
  else
    '.$' + mid
  end
end

def property(name) 

def property(name)
  valid_name?(name) ? ".#{name}" : "[#{name.inspect}]"
end

def valid_name?(name) 

def valid_name?(name)
  BASIC_IDENTIFIER_RULES =~ name and not(
    ES51_RESERVED_WORD          =~ name or
    ES3_RESERVED_WORD_EXCLUSIVE =~ name or
    IMMUTABLE_PROPS             =~ name
  )
end

def variable(name) 

def variable(name)
  valid_name?(name.to_s) ? name : "#{name}$"
end