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ruby--ruby/tool/ruby_vm/helpers/scanner.rb
Nobuyoshi Nakada ec03d13742
Fallback if Pathname#relative_path_from fails
It can fail due to different prefixes, e.g., drive letters or UNC
paths on DOSish platform.
2020-04-05 11:58:31 +09:00

53 lines
1.3 KiB
Ruby

#! /your/favourite/path/to/ruby
# -*- Ruby -*-
# -*- frozen_string_literal: true; -*-
# -*- warn_indent: true; -*-
#
# Copyright (c) 2017 Urabe, Shyouhei. All rights reserved.
#
# This file is a part of the programming language Ruby. Permission is hereby
# granted, to either redistribute and/or modify this file, provided that the
# conditions mentioned in the file COPYING are met. Consult the file for
# details.
require 'pathname'
# Poor man's StringScanner.
# Sadly https://bugs.ruby-lang.org/issues/8343 is not backported to 2.0. We
# have to do it by hand.
class RubyVM::Scanner
attr_reader :__FILE__
attr_reader :__LINE__
def initialize path
src = Pathname.new(__FILE__)
src = (src.relative_path_from(Pathname.pwd) rescue src).dirname
src += path
@__LINE__ = 1
@__FILE__ = src.to_path
@str = src.read mode: 'rt:utf-8:utf-8'
@pos = 0
end
def eos?
return @pos >= @str.length
end
def scan re
ret = @__LINE__
@last_match = @str.match re, @pos
return unless @last_match
@__LINE__ += @last_match.to_s.count "\n"
@pos = @last_match.end 0
return ret
end
def scan! re
scan re or raise sprintf "parse error at %s:%d near:\n %s...", \
@__FILE__, @__LINE__, @str[@pos, 32]
end
def [] key
return @last_match[key]
end
end