RE: first-class support for csharp in cc-mode.el

[dino chiesa <dpchiesa@hotmail.com>]

Hi Alan, nice to meet you.
Stefan, thanks for the input. 
 
acm@muc.de wrote:
>> I don't have much experience with emacs-devel, but what would it take
>> to get csharp to be supported as a first-class (built-in) language in
>> cc-mode?
>
> The current policy is not to add any more languages to the core of CC
> Mode, since it's hassle enough supporting the seven that are already
> there. There are certainly lots of users of C, C++, Java, several users
> of Objective C and AWK, but I just don't know about Pike and IDL. The
> problem is, when somebody implements support for a language directly in
> CC Mode and they move on a few years later, support for that langauge
> effectively vanishes. It was to fix this that Martin Stjernholm (my
> predecessor) implemented the c-lang-const mechanism.
>
 
Very clear. In that case I should be petitioning to get csharp-mode put into the emacs progmodes distrib separately, rather than petitioning to get csharp-mode folded into cc-mode.

> If the c-lang-const stuff is inadequate to support, say, C#, then I
> would prefer to amend CC Mode so that C# can be supported. It looks
> like the @"....." syntax will need such an amendment. This will
> probably involve a large change, since the use of \ as an escape
> character is firmly embedded in the very fabric of CC Mode. Is @ used
> for anything else in C#? Is it forbidden to have whitespace between @
> and "?
 
Yes, according to the lang spec, the @ must immediately be followed by a double-quote. The symbol is not used for anything else in the language. I just looked and this is called a "verbatim string literal".
http://www.go-mono.com/docs/index.aspx?link=ecmaspec%3a9.4.4.5

>
> In fact, I've just thought of a way of fixing this: in an after-change
> function, splat the syntax (using syntax-table text-properties) of
> anything within @"....". I think there's already a suitable hook in CC
> Mode for this.
>
 
Is this the approach used for handling of slashes within awk? (can be either a divide operator or a string delimiter). I tried wading through that code but didn't yet figure it out.
 
In csharp, it is not only a trailing slash that is special - the verbatim string also allows verbatim newlines in the string. This is legal:
 
var s = @"The quick brown fox
jumps over the lazy dog";
 
and results in a string with a \n between the 4th and 5th words.
 
I don't know how that might affect the final design of a solution, or if it recommends or disrecommends Stefan's suggestion to worry only about the final slash. 
 
 

>> I have no idea if this is a friendly proposal or not, but it would
>> make things nice for people who write C# and use emacs.
>
> Thanks for the proposal! Constructive suggestions are always welcome at
> CC Mode. By the way, CC Mode has its own mailing list at
> bug-cc-mode@gnu.org and is hosted on sourceforge for historical reasons.
>
 
Ah, very good. Is bug-cc-mode intended to serve discussion related only to bugs or potential bugs, or is it also good for random discussion or questions from cc-derived modes? I mean, if I were to ask specifically about the verbatim string literals, should I ask on emacs-devel or is it better on bug-cc-mode ?

>> There are still a few issues with that C# mode - lambdas have no
>> special support, and the new dynamic keyword in .NET 4.0 isn't there
>> (simple to add), and there is the literal string thing I described in
>> my other mail thread - but mostly it works well. Including this would
>> provide a good baseline of support in emacs for C#.
>
> Those are all issues for C# Mode's maintainer.
>
 
Right, those are issues for me (and friends) to own. I wasn't really asking for *that*, although I may ask for specific advice on some of those in the future, after I take a run at them, I hope you don't mind.

My real goal regarding "first class support" is to make csharp-mode official and standard, so that someone downloading emacs 24 or 23.x will just get it. I had originally thought that meant major surgery on cc-mode, but you're telling me it could be simpler than that.
 

monnier@iro.umontreal.ca wrote:
>
> So you're moving towards a CC-mode which is more like
> a "generic" engine? That's good to hear. Do you intend to then move
> support for AWK, IDL, Java, etc.. outside of the core CC-mode as well?
>

I'll let Alan address that.  		 	   		  
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