1 files changed, 108 insertions, 0 deletions
diff --git a/tool/ruby_vm/helpers/dumper.rb b/tool/ruby_vm/helpers/dumper.rb
new file mode 100644
index 0000000000..8f14d90d1f
--- /dev/null
+++ b/tool/ruby_vm/helpers/dumper.rb
@@ -0,0 +1,108 @@
+#! /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 'erb'
+require_relative 'c_escape'
+
+class RubyVM::Dumper
+  include RubyVM::CEscape
+
+  # I learned this handy "super-private" maneuver from @a_matsuda
+  # cf: https://github.com/rails/rails/pull/27363/files
+  using Module.new {
+    refine RubyVM::Dumper do
+      private
+
+      def new_binding
+        # This `eval 'binding'` does not return the current binding
+        # but creates one on top of it.
+        return eval 'binding'
+      end
+
+      def new_erb spec
+        path  = Pathname.new __dir__
+        path += '../views'
+        path += spec
+        src   = path.read mode: 'rt:utf-8:utf-8'
+      rescue Errno::ENOENT
+        raise "don't know how to generate #{path}"
+      else
+        erb = ERB.new src, nil, '%-'
+        erb.filename = path.realpath.to_path
+        return erb
+      end
+
+      def finderb spec
+        return @erb.fetch spec do |k|
+          erb = new_erb k
+          @erb[k] = erb
+        end
+      end
+
+      def replace_pragma_line str, lineno
+        if str == "#pragma RubyVM reset source\n" then
+          return "#line #{lineno + 2} #{@file}\n"
+        else
+          return str
+        end
+      end
+
+      public
+
+      def do_render source, locals
+        erb = finderb source
+        bnd = @empty.dup
+        locals.each_pair do |k, v|
+          bnd.local_variable_set k, v
+        end
+        return erb.result bnd
+      end
+
+      def replace_pragma str
+        return str                                 \
+          . each_line                              \
+          . with_index                             \
+          . map {|i, j| replace_pragma_line i, j } \
+          . join
+      end
+    end
+  }
+
+  def initialize path
+    @erb   = {}
+    @empty = new_binding
+    dst    = Pathname.new Dir.getwd
+    dst   += path
+    @file  = cstr dst.realdirpath.to_path
+  end
+
+  def render partial, locals: {}
+    return do_render "_#{partial}.erb", locals
+  end
+
+  def generate template
+    str = do_render "#{template}.erb", {}
+    return replace_pragma str
+  end
+
+  private
+
+  # view helpers
+
+  alias cstr rstring2cstr
+  alias comm commentify
+
+  def render_c_expr expr
+    render 'c_expr', locals: { expr: expr, }
+  end
+end