Re: 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