Is there a standard function that combines take() and popFrontExactly()

[realhet]

On Monday, 14 December 2020 at 14:16:41 UTC, Dukc wrote:
> On Friday, 11 December 2020 at 19:07:23 UTC, realhet wrote:
>> I've just made this unicode wordreplacer function working, but 
>> It seems not too nice and functional-ish.
>> Are there ways to make it more simple?
>
>
> To answer the title, yes there is:
>

Thanks for ideas!

Yesterday I ended up making this helper funct:
auto fetchFrontExactly(R)(ref R r, size_t n) if(isInputRange!R){
     auto res = r.takeExactly(n);
     r.popFrontExactly(n);
     return res;
}

Now I leaned from you: refRange and take-s ability to pop 
elements from a refRange.
That's what I was needed!

Now the 2 aproach looks like:

string replaceWords(alias fun = isWordChar)(string str, string 
from, string to){
     if(1){
         auto fetchAndReplace(Tuple!(bool, uint) p){
             auto act = refRange(&str).take(p[1]).text;
             return p[0] && act==from ? to : act;
         }
         return str.map!fun
                   .group
                   .map!fetchAndReplace
                   .join;
     }else{
         string res;
         foreach(isWord, len; str.map!fun.group){
             auto act = (&str).refRange.take(len).text;
             res ~= (isWord && act==from ? to : act);
         }
		return(res);
     }
}

They are the same thing, but the first looks nicer because it is 
a processing pipe with the state modifying thing extracted to a 
named function (so that's makes the pipe more understandable).
However in the foreach version I can have meaningful parameter 
names: (isWord, len) instead of a tuple.

I don't want to do functional programming just for itself. I'm 
just learning it, and want to understand it better. I already 
found a lot of good uses of it for my tasks and I still discover 
a lot of cool stuff.

Thanks again!