[Mono-devel-list] ICodeParser && Mono

[Jonathan Pryor]

Below...

On Wed, 2004-02-04 at 13:21, Christian Birkl wrote:
> Hi all,
> 
> Is there something equivalent to Microsoft.CSharp namespace in Mono? I
> can't find any in the current class/ directory in recent cvs. I'm
> specifically interested in Microsoft.CSharp.CSharpProvider. I'd like to
> do some code analysing stuff via ICodeProvider, which can create a
> CodeCompileUnit via .CreateParser().Parse(). This would be a much nicer
> way than doing the parsing on my own. But unfortuntly .CreateParser() is
> defined to *always* return null. It would be nice if Mono would break
> this MS behaviour (or somehow provide a second .CreateParser() method.).

Are you sure it's not CSharpCodeProvider?  There's one in 
<cvs root="mcs"/>/class/System/Microsoft.CSharp/CSharpCodeProvider.cs.

There's also a Microsoft.CSharp namespace in class/Cscompgd.

I don't know if Mono would be willing to break compatibility, but I
suspect not.

> My second question is wether mcs (mono c# compiler) internally actually
> uses System.CodeDom for its code creation or not. And if yes, how can i
> access the CodeDom created by the parser?

I believe this is a misunderstanding of what CodeDom is for.  CodeDom
isn't for *parsing* code.  It's for *generating* code.  Not CIL code. 
Source code.

CodeDom would be used by e.g. VisualStudio for generating templates: you
would describe, via CodeDom, that you want a class (MyClass), with a
method (Main), and some comments ("Do something here").  This CodeDom
description could then be used to generate the template code in VB.NET,
C#, JavaScript...  Anything that has a CodeDom provider.  It's to
generate *human readable* source code.

This was discussed -- in excruciating depth because of perceived GPL
"backdoor" -- in May 2002, when miguel noted:

	The System.CodeDOM API is a mechanism to "build" source code 
	through an API.  It is just an abstraction so that ASP.NET can
	"create" pages built on a number of languages.

	Once you have constructed your "CodeDOM", it is written into a
	file, and an external compiler is invoked.  So there are no
	licensing problems.

See:	http://lists.ximian.com/archives/public/mono-list/2002-May/005929.html

To generate IL, System.Reflection.Emit is used.  This is what mcs does. 
You can also use PEAPI (in mcs CVS), or just directly emit the opcodes
(if you're writing in a non-managed environment).

I think PEAPI can also be used to parse existing IL code, but I'm not
entirely sure.

 - Jon