Module: Net::IMAP::ResponseParser::ParserUtils::Generator

Included in:
Net::IMAP::ResponseParser
Defined in:
lib/net/imap/response_parser/parser_utils.rb

Overview

:nodoc:

Constant Summary collapse

LOOKAHEAD =

:nodoc:

"(@token ||= next_token)"
SHIFT_TOKEN = 
"(@token = nil)"

Instance Method Summary collapse

Instance Method Details

#def_char_matchers(name, char, token) ⇒ Object

we can skip lexer for single character matches, as a shortcut



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# File 'lib/net/imap/response_parser/parser_utils.rb', line 17

def def_char_matchers(name, char, token)
  byte = char.ord
  match_name = name.match(/\A[A-Z]/) ? "#{name}!" : name
  char = char.dump
  class_eval "    # frozen_string_literal: true\n\n    # force use of #next_token; no string peeking\n    def lookahead_\#{name}?\n      \#{LOOKAHEAD}&.symbol == \#{token}\n    end\n\n    # use token or string peek\n    def peek_\#{name}?\n      @token ? @token.symbol == \#{token} : @str.getbyte(@pos) == \#{byte}\n    end\n\n    # like accept(token_symbols); returns token or nil\n    def \#{name}?\n      if @token&.symbol == \#{token}\n        \#{SHIFT_TOKEN}\n        \#{char}\n      elsif !@token && @str.getbyte(@pos) == \#{byte}\n        @pos += 1\n        \#{char}\n      end\n    end\n\n    # like match(token_symbols); returns token or raises parse_error\n    def \#{match_name}\n      if @token&.symbol == \#{token}\n        \#{SHIFT_TOKEN}\n        \#{char}\n      elsif !@token && @str.getbyte(@pos) == \#{byte}\n        @pos += 1\n        \#{char}\n      else\n        parse_error(\"unexpected %s (expected %p)\",\n                    @token&.symbol || @str[@pos].inspect, \#{char})\n      end\n    end\n  RUBY\nend\n", __FILE__, __LINE__ + 1

#def_token_matchers(name, *token_symbols, coerce: nil, send: nil) ⇒ Object

TODO: move coersion to the token.value method?



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# File 'lib/net/imap/response_parser/parser_utils.rb', line 62

def def_token_matchers(name, *token_symbols, coerce: nil, send: nil)
  match_name = name.match(/\A[A-Z]/) ? "#{name}!" : name

  if token_symbols.size == 1
    token   = token_symbols.first
    matcher = "token&.symbol == %p" % [token]
    desc    = token
  else
    matcher = "%p.include? token&.symbol" % [token_symbols]
    desc    = token_symbols.join(" or ")
  end

  value = "(token.value)"
  value = coerce.to_s + value   if coerce
  value = [value, send].join(".") if send

  raise_parse_error = "    parse_error(\"unexpected %s (expected \#{desc})\", token&.symbol)\n  RUBY\n\n  class_eval <<~RUBY, __FILE__, __LINE__ + 1\n    # frozen_string_literal: true\n\n    # lookahead version of match, returning the value\n    def lookahead_\#{name}!\n      token = \#{LOOKAHEAD}\n      if \#{matcher}\n        \#{value}\n      else\n        \#{raise_parse_error}\n      end\n    end\n\n    def \#{name}?\n      token = \#{LOOKAHEAD}\n      if \#{matcher}\n        \#{SHIFT_TOKEN}\n        \#{value}\n      end\n    end\n\n    def \#{match_name}\n      token = \#{LOOKAHEAD}\n      if \#{matcher}\n        \#{SHIFT_TOKEN}\n        \#{value}\n      else\n        \#{raise_parse_error}\n      end\n    end\n  RUBY\nend\n"