1 files changed, 124 insertions, 0 deletions
diff --git a/ext/ripper/tools/preproc.rb b/ext/ripper/tools/preproc.rb
new file mode 100644
index 0000000000..5e8a6e0cb5
--- /dev/null
+++ b/ext/ripper/tools/preproc.rb
@@ -0,0 +1,124 @@
+# frozen_string_literal: true
+# $Id$
+
+require 'optparse'
+
+def main
+  output = nil
+  template = nil
+  parser = OptionParser.new
+  parser.banner = "Usage: #{File.basename($0)} [--output=PATH] [--template=PATH] <parse.y>"
+  parser.on('--output=PATH', 'An output file.') {|path|
+    output = path
+  }
+  parser.on('--template=PATH', 'An template file.') {|path|
+    template = path
+  }
+  parser.on('--help', 'Prints this message and quit.') {
+    puts parser.help
+    exit true
+  }
+  begin
+    parser.parse!
+  rescue OptionParser::ParseError => err
+    warn err.message
+    abort parser.help
+  end
+  out = "".dup
+  if ARGV[0] == "-"
+    unless ARGV.size == 2
+      abort "wrong number of arguments (#{ARGV.size} for 2)"
+    end
+    process STDIN, out, ARGV[1], template
+  else
+    unless ARGV.size == 1
+      abort "wrong number of arguments (#{ARGV.size} for 1)"
+    end
+    File.open(ARGV[0]) {|f|
+      process f, out, ARGV[0], template
+    }
+  end
+  if output
+    File.write(output, out)
+  else
+    print out
+  end
+end
+
+def process(f, out, path, template)
+  prelude f, out
+  grammar f, out
+  usercode f, out, path, template
+end
+
+require_relative 'dsl'
+
+def generate_line(f, out)
+  while line = f.gets
+    case
+    when gen = DSL.line?(line, f.lineno)
+      out << gen.generate << "\n"
+    when line.start_with?("%%")
+      out << "%%\n"
+      break
+    else
+      out << yield(line)
+    end
+  end
+end
+
+def prelude(f, out)
+  @exprs = {}
+  generate_line(f, out) do |line|
+    if (/^enum lex_state_(?:bits|e) \{/ =~ line)..(/^\}/ =~ line)
+      case line
+      when /^\s*(EXPR_\w+),\s+\/\*(.+)\*\//
+        @exprs[$1.chomp("_bit")] = $2.strip
+      when /^\s*(EXPR_\w+)\s+=\s+(.+)$/
+        name = $1
+        val = $2.chomp(",")
+        @exprs[name] = "equals to " + (val.start_with?("(") ? "<tt>#{val}</tt>" : "+#{val}+")
+      end
+    end
+    line
+  end
+end
+
+def grammar(f, out)
+  generate_line(f, out) do |line|
+    case line
+    when %r</\*%%%\*/>
+      "#if 0\n"
+    when %r</\*%>
+      "#endif\n"
+    when %r<%\*/>
+      "\n"
+    else
+      line
+    end
+  end
+end
+
+def usercode(f, out, path, template)
+  require 'erb'
+  lineno = nil
+  src = nil
+  compiler = ERB::Compiler.new('%-')
+  compiler.put_cmd = compiler.insert_cmd = "out.<<"
+
+  if template
+    File.open(template) do |f|
+      out.clear
+      lineno = f.lineno
+      src, = compiler.compile(f.read)
+      path = template
+    end
+  else
+    lineno = f.lineno
+    src, = compiler.compile(f.read)
+  end
+
+  eval(src, binding, path, lineno)
+end
+
+main