module Erubis::OptimizedGenerator

def self.supported_properties()  # :nodoc:
  return []
end

def add_expr_debug(src, code)
  code.strip!
  s = (code.dump =~ /\A"(.*)"\z/) && $1
  src << ' $stderr.puts("*** debug: ' << s << '=#{(' << code << ').inspect}");'
end

def add_expr_escaped(src, code)
  unless @initialized; src << "_buf = ''"; @initialized = true; end
  switch_to_expr(src)
  src << " << " << escaped_expr(code)
end

def add_expr_literal(src, code)
  unless @initialized; src << "_buf = ''"; @initialized = true; end
  switch_to_expr(src)
  src << " << (" << code << ").to_s"
end

def add_postamble(src)
  #super if @initialized
  src << "\n_buf\n" if @initialized
end

def add_preamble(src)
  #@initialized = false
  #@prev_is_expr = false
end

def add_stmt(src, code)
  switch_to_stmt(src) if @initialized
  #super
  src << code
  src << ';' unless code[-1] == ?\n
end

def add_text(src, text)
  return if text.empty?
  if @initialized
    switch_to_expr(src)
    src << " << '" << escape_text(text) << "'"
  else
    src << "_buf = '" << escape_text(text) << "';"
    @initialized = true
  end
end

def escape_text(text)
  text.gsub(/['\\]/, '\\\\\&')   # "'" => "\\'",  '\\' => '\\\\'
end

def escaped_expr(code)
  @escapefunc ||= 'Erubis::XmlHelper.escape_xml'
  return "#{@escapefunc}(#{code})"
end

def init_generator(properties={})
  super
  @escapefunc ||= "Erubis::XmlHelper.escape_xml"
  @initialized = false
  @prev_is_expr = false
end

def switch_to_expr(src)
  return if @prev_is_expr
  @prev_is_expr = true
  src << ' _buf'
end

def switch_to_stmt(src)
  return unless @prev_is_expr
  @prev_is_expr = false
  src << ';'
end