Burton Radons wrote:
Andrei Alexandrescu Wrote:
This is a known problem for hich we will provide a solution.
If you have something which works everywhere please tell us because
we've been trying to find one for a long time, but as far as I know
there is no solution. The best I've ever gotten to is:
// "A" means that the constness of the return type depends upon the
constness of the argument. There are dozens of ways to specify the
same thing. const (A) mstring match (const (A) mstring text, RE
expression);
But setting aside whether that helps or hinders self-documentation,
that's far from the only place at which you put mutable data through
a const section that you need to modify later. What if the function
were instead:
struct REMatch { string match; /// The matched string. size_t offset;
/// Offset within the string where the match occurs. string []
groups; /// Matched groups.
this (string text); }
What am I going to do about this now without using templates? If you
define a special syntax to make this work, then I can give you
something even further which won't.
The problem is you set up artificially constrained rules, i.e. "without
using templates". You can't use the same struct to store mutable types
and non-mutable types mixed with always-mutable types, and for good
reasons. No type system will allow 100% of the correct programs to run.
Why the fuss. Use a gorram template and call it a day.
Andrei
