|Posted by Dmitry Olshansky|
in reply to Tobias Pankrath
Posted in reply to Tobias Pankrath
On 24.07.2011 20:46, Tobias Pankrath wrote:
> I needed a small script for a project of mine and hacked one in python.
> Since I want to learn some D, I tried to convert it. Took me a bit longer
> than I thought, because I got delayed by this lovely error message:
> Error: template instance ambiguous template declaration
> std.array.replace(R1,R2,R3) if (isDynamicArray!(R1)&& isForwardRange!(R2)
> && isForwardRange!(R3)&& (hasLength!(R3) || isSomeString!(R3))) and
> std.regex.replace(Range,Engine,String) if (is(Unqual!(Engine) == Regex!
> Took me a while do understand it, but it seems that I've got a name
> collision. What I don't understand is, why is the compiler unable to
> tell two functions, one with two parameter and one with three, apart?
Apparently, this overload of replace has 3 parameters: input, what to replace and a replacement. It searches and replaces all occurrences.
I've hit the same issue while implementing a replacement for std.regex, the underlying problem I think is that
std.array.replace has a way too lousy template constraint. According to source it checks only if it's input is a range or string, but if it has compatible type is *not* checked.
Now with std.regex since RegexMatch is ForwardRange it's of course matches, but element type is string/wstring/dstring, while I suppose std.array in this case would need element type of dchar.
It hadn't occurred to me that somebody will hit this anytime soon, so now I might roll out a pull request sooner :)