On Thu, 24 Feb 2011 02:39:36 -0500, Jonathan M Davis <[email protected]>
wrote:
On Wednesday 23 February 2011 22:41:53 Christopher Bergqvist wrote:
Hi!
I've run into an issue which I don't understand.
Boiled down code:
import std.regex;
void main()
{
//string str = "sdf"; // works
//const string str = "sdf"; // doesn't work
immutable str = "sdf"; // doesn't work
auto pat = regex(", *");
auto split = splitter(str, pat);
}
Error:
/Library/Compilers/dmd2/osx/bin/../../src/phobos/std/regex.d(3022):
Error: this is not mutable
Should splitter() be able to cope with const/immutable ranges?
(That's with the latest official v2.052 dmd/phobos distribution for
mac. I got the same error before upgrading from the v2.051
also).
Pretty much _nothing_ copes with const or immutable ranges. And if you
think
about it, it generally makes sense. You can't pop the front off of a
const or
immutable range. So, how could you possibly process it? The are some
cases where
having tail const with ranges would work (assuming that we could have
tail const
with ranges - which we currently can't), but on the whole, const and
immutable
ranges don't really make sense. They can hold const or immutable data,
but a
const or immutable range is pretty useless on the whole.
The issue is not so much that the range is const or immutable, but that
splitter uses IFTI to determine the parameter type. If splitter could use
the tail-* version of itself when its argument was fully const or fully
immutable, then it would work.
-Steve
