Truly lazy ranges, transient .front, and std.range.Generator

[Alex Parrill via Digitalmars-d]

On Saturday, 15 August 2015 at 10:06:13 UTC, Joseph Rushton 
Wakeling wrote:
> ...

I had this issue recently when reading from a command-line-style 
TCP connection; I needed to read the line up to the \n separator, 
but consuming the separator meant waiting for the next byte that 
would never arrive unless a new command was sent.

So I made a wrapper range that evaluates the wrapped range's 
popFront only when front/empty is first called ("just in time"). 
Source code here: 
https://gist.github.com/ColonelThirtyTwo/0dfe76520efcda02d848

You can throw it in a UFCS chain anywhere except (for some 
reason) after something that takes a delegate template parameter 
like map. For example:

     auto reader = SocketReader(socket).joiner.jitRange.map!(byt 
=> cast(char) byt);