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 :-)
