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-rw-r--r--tool/ruby_vm/helpers/scanner.rb49
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diff --git a/tool/ruby_vm/helpers/scanner.rb b/tool/ruby_vm/helpers/scanner.rb
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+#! /your/favourite/path/to/ruby
+# -*- mode: ruby; coding: utf-8; indent-tabs-mode: nil; ruby-indent-level: 2 -*-
+# -*- 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'
+require 'strscan'
+
+class RubyVM::Scanner
+ attr_reader :__FILE__
+ attr_reader :__LINE__
+
+ def initialize path
+ src = Pathname.new __dir__
+ src += path
+ @__LINE__ = 1
+ @__FILE__ = src.realpath.to_path
+ str = src.read mode: 'rt:utf-8:utf-8'
+ @scanner = StringScanner.new str
+ end
+
+ def eos?
+ @scanner.eos?
+ end
+
+ def scan re
+ ret = @__LINE__
+ match = @scanner.scan re
+ return unless match
+ @__LINE__ += match.count "\n"
+ return ret
+ end
+
+ def scan! re
+ scan re or raise sprintf "parse error at %s:%d near:\n %s...", \
+ @__FILE__, @__LINE__, @scanner.peek(32)
+ end
+
+ def [] key
+ return @scanner[key]
+ end
+end