Errors in TDPL

[Alix Pexton]

On 21/06/2010 21:51, Tomek Sowiński wrote:
> Dnia 21-06-2010 o 21:57:49 Alix Pexton <alix.DOT.pexton at gmail.dot.com>
> napisał(a):
>
>> There is only one mention of lazy evaluation in the index and it
>> doesn't mention the lazy k/w at all. I seem to remember Andrei
>> dislikes it, but also that there is another way to get function params
>> to be evaluated lazily without using it.
>
> Yeah, speaking of which - what happened to that proposal*?
>
> *The proposal AFAIR was (correct me if wrong): if a function has a
> parameterless delegate as a parameter, then on the call site any
> expression in the delegate slot is implicitly turned into a delegate. I
> think the delegate ought to be pure to make the magic happen.
>
> Yeah, speaking of which - do/will we have pure delegates?
>
>
> Tomek

This is the "trick" I was refering to, from a post by the programmer 
formerly known as downs...

Amusing D facts: typesafe variadic arrays are lazy!
 >
 > Did you know the following code compiles?
 >
 > > > module test;
 > > >
 > > > import std.stdio;
 > > >
 > > > void Assert(bool cond, string delegate()[] dgs...) {
 > > >   debug if (!cond) {
 > > >     string str;
 > > >     foreach (dg; dgs) str ~= dg();
 > > >     throw new Exception(str);
 > > >   }
 > > > }
 > > >
 > > > void main() {
 > > >   Assert(false, "O hai thar! ");
 > > > }
 >
 > It's true! :)

A...