Why does std.string.munch take a string ref?

[monarch_dodra via Digitalmars-d]

On Wednesday, 11 June 2014 at 21:10:42 UTC, Sean Kelly wrote:
> On Wednesday, 11 June 2014 at 21:07:18 UTC, w0rp wrote:
>> On Wednesday, 11 June 2014 at 20:27:41 UTC, Sean Kelly wrote:
>>> It's the only function in std.string that takes a string by 
>>> ref instead of by value, and this screws up call chaining.  
>>> What's the reason for this?
>>
>> munch modifies the string you give it.
>
> Yes, but why does it do this when it could leave the string 
> as-is and return a modified slice instead, like all the other 
> routines in std.string?

I think it's because it "returns" both the munched data, and the 
modified string:

string s = "123abc";
string t = munch(s, "0123456789");
assert(t == "123" && s == "abc");

But it would indeed be more natural to simply return the updated 
"s". It's what things like "find" or "stripLeft" do anyways, and 
that works fine.