Creating InputRanges from strings, files etc.

[rikki cattermole]

On 09/11/2018 2:58 AM, Vinay Sajip wrote:
> Excuse my ignorance, but from looking at the documentation on std.range 
> and a quick skim of the guides mentioned there near the top, I can't see 
> what the simple way is of creating an InputRange!(ubyte) from strings, 
> files etc. I would have expected to find something in the DLang Tour 
> about this, but couldn't find anything. Please can someone tell me how 
> to do it? Just to be clear, I want to create an object which is an 
> InputRange!(ubyte) and pass that around, rather than e.g. iterate over a 
> string or a file.

TLDR of how to write an input range:

struct MyInputRange {
	ubyte[] input;

	@property {
		ubyte front() {
			return this.input[0];
		}

		bool empty() {
			return this.input.length == 0;
		}
	}

	void popFront() {
		this.input = this.input[1 .. $];
	}
}

import std.stdio;

void main() {
     foreach(b; MyInputRange([1, 2, 3])) {
     	writeln(b);
     }
}