On 2011-02-01 11:31:54 -0500, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> said:
On 2/1/11 9:21 AM, Don wrote:
Jonathan M Davis wrote:
On Sunday 30 January 2011 05:28:36 SHOO wrote:
To be frank, I don't think that such a helper is necessary.
I think these helpers will harm intuitive readability of unittest code.
For unittest code, it is necessary to be able to understand easily even
if without the document.
Do you really find
assertPred!"=="(min(5, 7), 5);
to be all that harder to understand than
assert(min(5, 7) == 5);
I do. *Much* harder. Factor of two, at least.
In absolute terms, not so much, because it was the original assert is
very easy to understand. But the relative factor matters enormously.
Much as comparing:
a.add(b);
a += b;
And I think this is a very important issue.
>I don't see how these functions could be anything but an improvement.
> But even if they get into Phobos, you obviously don't have to use them.
This is not true. Including them in Phobos gives a legitimacy to that
style of programming. It's a role model.
Including stuff like this could give D a reputation for lack of
readability. My belief is that right now, the #1 risk for Phobos is that
it becomes too clever and inaccessible.
IMHO, something simple which has any appearance of being complicated,
needs a VERY strong justification.
One more thought. Don, you are in the unique position to (a) be
strongly opinionated about this and (b) have insider knowledge about
the compiler. You could, therefore, modify the definition of assert to
automatically rewrite failed calls of the form assert(expr == expr),
assert(expr < expr) etc. etc. as discussed in this thread.
The rewritten forms would give the runtime the compared values to do
whatever with. There is the sensitive issue of converting values of
arbitrary types to strings at the runtime level, but we may be able to
find a good solution to that.
TypeInfo holds a pointer to the toString function, so if the compiler
passes the two operands as D-style variadic arguments to the assert
handler, the assert handler can use toString to print them. The
operator should be passed as a string.
--
Michel Fortin
michel.for...@michelf.com
http://michelf.com/
