Re: [boost] [preprocessor] What syntax to present to the user

From: Loïc Joly (loic.actarus.joly_at_[hidden])
Date: 2005-05-17 15:01:55

Paul Mensonides a écrit :

>Hi Loïc.
>
>Okay, I have a little more time now.
>
>  
>
Thank you for your help, it helps me clarify some fuzzy points.

>>I'm trying to use the boost preprocessor library to allow the 
>>user to define "rich" enums, for instance enums that cannot 
>>be converted to int, whose values can be displayed in human 
>>readable form on a stream...
>>    
>>
>
>You might already know that there are several fancy enum implementations around.
>However, I'm not sure if any them fit what you're looking for.  Specifically,
>enumerators that cannot be converted to integers.  What you want, AFAICT, is a
>set of symbols only that share a common type.  You may want to look for existing
>implementations first.
>  
>
I do this for a personnal project, part of which is to improve my 
skills, so even if I crave for re-use, not this time. By the way, I had 
a little check, and no fancy enum I have seen seems to have reached a 
wide acceptance yet, or to cover my requirements. Maybe I will call my 
system yafe (yet another fancy enum) :).

[snip example]

>In other words, the importance of debuggability greatly depends on what you're
>generating--i.e. what you want the preprocessor to write for you.  If it is
>something complex, particularly if it can fail inside the specific generated
>code, then debuggability is more important.
>  
>
>>And now, the questions :
>>Which writing do you think would be best ? Why ? Are there 
>>other possibilities I overlooked ? Is is possible to have a 
>>syntax like 1/ and 2/ with good debugability ?
>>    
>>
>
>To the last, yes.  But the point at which it is debugged is different.  Instead,
>when you write something like the above, you debug the preprocessor metaprogram
>to make sure it is generating what you want, and then you debug the *pattern*
>that it is generating by creating instances of the pattern (like color above),
>and making sure that it works correctly.  Once that is done, you shouldn't have
>to debug it again.
>
Ok, I think I can see your point. I guess that my reluctance was due to 
the fact that since I am not fluent in cpp, I was afraid to create a 
macro that would span on many lines. Let's go for this syntax then. 
Maybe I will publish the result in the mailing list files area, if I 
think "yafe" can be of interrest to other people.

Regards,

-- 
Loïc