Template constraints error messages using cputs()

[Mafi]

Am 08.08.2010 17:41, schrieb bearophile:
> BCS:
>
>> All the issues you address up to where you propose ctputs are bugs in DMD,
>> not pragma(msg,...) as for ctputs as a /replacement/ see my replay to the
>> bug.
>
> Thank you for this answer and the answer in bugzilla. I explain the problems I find while I program in D, and sometimes I try to give a starting point for a solution, but usually it's not hard to find solutions better than the ones I suggest.
>
> I have written an answer in Bugzilla, I don't know if it's enough.
>
>
>> you will not convince me that what it currently does is less than /very useful/.
>
> You are right :-)
>
>
>> My minimum requirements for a pragma(msgm...) replacement would be that it
>> take any expression that results in an immutable(char[]) and, at compile
>> time (and only compile time) during the semantic pass (while the code is
>> processed, not evaluated) output the string.
>
> I'd like to ctputs() to act as std.c.stdio.puts() if the function is run at run time.
>
>
>> The major cases where your ctputs fails on this are inside a function that
>> can be evaluated via CTFE:
>> - If placed in a RT loop it could be evaluated to many times.
>> - If placed in a code path that isn't hit via CTFE, it never outputs anything.
>> - If the function gets run at RT, then you need to add a guard to prevent
>> it from generating output at RT.
>
> This is by design.
>
> But I understand your point, ctputs seems designed for a purpose different than pragma(msg), it doesn't seem a replacement. ctputs is meant as a way to print strings from function if you call the function both at runtime or compile time with CTFE. pragma(msg) is meant to show a message at compile time. So pragma(msg) needs to be debugged and then kept.
>

I see the need for ctputs-like construct but I don't like the name. What 
about simply making puts magically ctfe-able. The runtime behavior is 
clearly defined and the compiler has to to simply catch calls to the 
real puts when ctfe-ing and replace it with it's implemantation.
What do you, bearophile and others, think?

> I probably have update the bug report, and I'd like to split it in a pragma(msg) bug report (essentially to make it test its input argument better), plus an enhancement request for a ctputs() probably in std.intrinsic :-)