On Tuesday, 16 May 2017 at 18:57:37 UTC, H. S. Teoh wrote:
To me, it's actually worse, because now you have a visual
conflation with do-loops.
Overall, what I don't like about contract syntax is that it is
so unbearably verbose. It's not just the in and out blocks and
the (IMO redundant) marking of the function body; it's also the
repeated 'assert's that occur in the in and out blocks.
int foo(T, U)(T t, U u)
if (sigContraints!T && sigConstraints!U)
in
{
assert(t > 0 && u < 10);
}
out(val)
{
assert(val > 1 && val < 5);
}
body
{
// function body here
}
I understand this DIP is only to address the `body` part of
this ugly verbosity, but imagine how much better it would be if
we could write something like this instead:
int foo(T, U)(T t, U u)
if (sigConstraints!T && sigConstraints!U)
in (t > 0 && u < 10)
out(foo > 1 && foo < 5 )
{
// function body here
}
This is just tentative example syntax, of course. We can argue
over its fine points later, but the point is that the current
syntax is far too verbose, and can easily be reduced to half
the number of lines. Merely changing `body` to `do` does
nothing to address this, and seems to me to be just more
useless churn, replacing one bit of verbosity with another bit
of verbosity. (Not to mention the IMO very ugly syntax clash
with do-loops, which will reduce code readability even more.)
T
I think there are several issues at hand, and they need to be
dealt with individually:
1. `body` is a very useful identifier. It would be nice to have
it available.
2. Contract syntax is too verbose.
3. a. Some people think code looks better with a keyword, e.g.
`body`, `do`, etc. distinguishing the function from the contracts.
3. b. Other people think that such a keyword is unnecessarily
redundant and does not justify its own existence.
I think the thread will be more productive if the posters commit
to answering just one of these issues, and reserve other issues
for other threads. As the DIP in question is directly meant to
address issue #1, it makes sense to try to solve that problem and
only that problem here.
