1 files changed, 20 insertions, 0 deletions
diff --git a/tool/pure_parser.rb b/tool/pure_parser.rb
new file mode 100644
index 0000000000..aa00a2defa
--- /dev/null
+++ b/tool/pure_parser.rb
@@ -0,0 +1,20 @@
+#!/usr/bin/ruby -pi
+BEGIN {
+  require_relative 'colorize'
+
+  colorize = Colorize.new
+  file = ARGV.shift
+  begin
+    version = IO.popen(ARGV+%w[--version], &:read)
+  rescue Errno::ENOENT
+    abort "Failed to run `#{colorize.fail ARGV.join(' ')}'; You may have to install it."
+  end
+  unless /\Abison .* (\d+)\.\d+/ =~ version
+    puts colorize.fail("not bison")
+    exit
+  end
+  exit if $1.to_i >= 3
+  ARGV.clear
+  ARGV.push(file)
+}
+$_.sub!(/^%define\s+api\.pure/, '%pure-parser')