Added Melbourne parser extension.

The basic machinery is in place but the processor is all stubs. Both
String#to_ast and File.to_ast "work". The next steps are:

1. Get a harness in place to run the specs
2. Start adding functionality to the processor methods
3. Fix the arguments passed to processor methods from the visitor
4. Augment the compiler Node classes with additional methods as needed
5. Get all specs passing
6. Remove the dependencies on libmpa, libmquard, libcchash

lib/bin/compile.rb

@@ -75,6 +75,10 @@ def add_include(inc)
     @includes << "-I#{inc}"
   end
 
+  def add_pre_compile(block)
+    @block = block
+  end
+
   attr_reader :output
 
   def calculate_output
@@ -151,10 +155,14 @@ def link_options
     return opts.join(" ")
   end
 
+  def pre_compile
+    @block.call if @block
+  end
+
   def compile_files
     @objects = []
     @files.each do |file|
-      out = file.sub /\.c$/, '.o'
+      out = file.sub /\.cpp|\.c$/, '.o'
 
       cmd = "#{compiler} #{compile_options} -c -o #{out} #{file}"
       puts cmd if $VERBOSE
@@ -203,8 +211,8 @@ def name(name)
       @ec.set_output name
     end
 
-    def files(glob)
-      Dir[glob].each { |f| @ec.add_file f }
+    def files(*glob)
+      Dir[*glob].each { |f| @ec.add_file f }
     end
 
     def flags(*args)
@@ -219,6 +227,10 @@ def includes(*args)
       args.each { |a| @ec.add_include a }
     end
 
+    def pre_compile(&block)
+      @ec.add_pre_compile block
+    end
+
     def setup
       $ec_dsl = self
     end
@@ -282,9 +294,10 @@ def extension
   Dir.chdir file
   load "build.rb"
 
+  ext.pre_compile
   ext.compile
 
-elsif file.suffix?(".c")
+elsif file.suffix?(".c") or file.suffix?(".cpp")
   puts "Compiling extension #{file}..." if $VERBOSE
 
   ext = ExtensionCompiler.new(flags, ARGV)

lib/ext/melbourne/build.rb

@@ -0,0 +1,14 @@
+extension do |e|
+  e.name 'melbourne'
+  e.files '*.c', '*.cpp'
+  e.includes '.', '../../../vm/external_libs/libbstring',
+             '../../../vm/external_libs/libmquark',
+             '../../../vm/external_libs/libmpa',
+             '../../../vm/external_libs/libcchash'
+
+  e.pre_compile do
+    if File.mtime("grammar.y") > File.mtime("grammar.cpp")
+      system "bison -o grammar.cpp grammar.y"
+    end
+  end
+end

lib/ext/melbourne/extconf.rb

@@ -0,0 +1,11 @@
+require 'rbconfig'
+require 'mkmf'
+
+create_makefile('melbourne')
+
+File.open("Makefile","a+") do |f|
+  f.puts <<END
+grammar.cpp: grammar.y
+	bison -o grammar.cpp grammar.y
+END
+end