readln with buffer fails

[dcrepid via Digitalmars-d-learn]

On Wednesday, 29 October 2014 at 21:19:25 UTC, Peter Alexander 
wrote:
> You need to take a slice of the buffer:
>
> char[] buf = Input[];
> readln(buf);
> // line now in buf
>
> The reason for this is because you need to know where the 
> string ends. If you just passed in Input, how would you know 
> how long the line read was?

Thanks, that solves the problem.  I guess what confuses me is 
that Input isn't a slice, or at least not implicitly convertible 
to one.

Also, I've tried using Input[] directly at the callsite but 
apparently that would be an rValue, and D doesn't do rValues yet.

So here's a simple solution to reading a line using a fixed stack 
array:

     char[4096] Input;
     char[] InputSlice;  // actual slice of input'd text (instead 
of full 4K)
     size_t NumChars;

     while (NumChars == 0)
     {
         // readln(buf) requires a slice. Input isn't converted to 
one,
         // and readln() requires an rvalue for a buffer:
         char[] buf = Input[];
         NumChars = readln(buf);
         // Set InputSlice to range of text that was input, minus 
linefeed:
         InputSlice = chomp(buf[0 .. NumChars]);
         // Empty line?
         if (InputSlice == "")
             NumChars = 0;
     }

Thanks all for your help