module Erubis::SchemeGenerator

def self.supported_properties()  # :nodoc:
  return [
          [:func,  '_add',   "function name (ex. 'display')"],
          ]
end

def add_expr_debug(src, code)
  s = (code.strip! || code).gsub(/\"/, '\\"')
  src << "(display \"*** debug: #{s}=\")(display #{code.strip})(display \"\\n\")"
end

def add_expr_escaped(src, code)
  add_expr_literal(src, escaped_expr(code))
end

def add_expr_literal(src, code)
  code.strip!
  src << "(#{@func} #{code})"
end

def add_postamble(src)
  return unless @func == '_add'
  src << "\n" unless src[-1] == ?\n
  src << "  (reverse _buf))\n"
end

def add_preamble(src)
  return unless @func == '_add'
  src << "(let ((_buf '())) " + \
           "(define (_add x) (set! _buf (cons x _buf))) "
  #src << "(let* ((_buf '())" + \
  #             " (_add (lambda (x) (set! _buf (cons x _buf))))) "
end

def add_stmt(src, code)
  src << code
end

def add_text(src, text)
  return if text.empty?
  t = escape_text(text)
  if t[-1] == ?\n
    t[-1, 1] = ''
    src << "(#{@func} \"" << t << "\\n\")\n"
  else
    src << "(#{@func} \"" << t << '")'
  end
end

def escape_text(text)
  @table_ ||= { '"'=>'\\"', '\\'=>'\\\\' }
  text.gsub!(/["\\]/) { |m| @table_[m] }
  return text
end

def escaped_expr(code)
  code.strip!
  return "(#{@escapefunc} #{code})"
end

def init_generator(properties={})
  super
  @escapefunc ||= 'escape'
  @func = properties[:func] || '_add'   # or 'display'
end