[antlr-interest] Visual Studio syntax highlighting for an Antlrgrammar

[Micheal J]

> One disadvantage of Babel is that it's old-skool C++.  
> However, Visual 
> Studio 2005 expands this API with managed wrappers enabling an entire 
> language service to be implemented in C#.  (The C# classes 
> lack flex/bison 
> integration however.)

There are C# ports of CUP and JFlex. And there is also the similar CSTools
suite and Mono's Jay/C#+flex port too. All will allow flex/bison-like
grammars to be used with a few changes with C#.

I've just added a "%antlr" mode to C# Flex in fact to make csflex->ANTLR
integration easier. Needs testing. Sowhatdoyousay?...  ;-)

> The required 
> C# interface looks like this:
> 
>    void IScanner.SetSource(string source, int offset);
>    bool IScanner.ScanTokenAndProvideInfoAboutIt(TokenInfo tokenInfo,
>      ref int state);
> 
> The idea is that the editor passes a single line of text to 
> SetSource(), 
> and then calls ScanTokenAndProvideInfoAboutIt() repeatedly to 
> obtain the 
> colored tokens for that line.  In this situation, the only context 
> available to the lexer is a single "state" integer (which for 
> Babel stores 
> flex's "yy_start" global variable).  Unfortunately, since Antlr is a 
> recursive descent design, there isn't an obvious way to 
> restart the lexer 
> e.g. in the middle of a multiline comment.  Has anyone else 
> dealt with this 
> problem before?

I think Bodgan Mitu did. And the ANTLRStudio guy too I would guess (if he
indeed uses ANTLR for his lexing/parsing).

> More generally, has anyone implemented a Visual Studio 
> language service 
> using an Antlr grammar?  Or, is it difficult to port an Antlr 
> grammar to 
> flex/bison?  :-)

I'm no flex/bison expert but, I shouldn't think so as long as you aren't
using too much of the cool technology in ANTLR (e.g. sempreds).

Micheal