PHP-style (embedded variables) print statements

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I hate it when people use this in PHP and Perl, it can be un-greppable and there's so much ambiguity when using arrays and similar.

Still, pretty cool to be able to do it in D.  Just shows D's strengths.

-[Unknown]


Don Clugston Wrote:

> With CTFE and text mixins, it is now reasonably straightforward to 
> implement PHP-style 'dollar' embedded variables, in a type-safe manner.
> 
> For example, the attached code (rough draft) allows you to write things 
> like:
> 
> int i;
> const k = 8;
> char [] str;
> mixin(dprint("current=$i next=$(i+1) const=$(k*3) $str\n"));
> 
> which is typesafe, converts all compile-time constants directly into the 
> format string, and converts everything else into a simple printf() call. 
> The mixin line above becomes
> 
> printf("current=%d next=%d const=24 %.*s\n", i, i+1, str);
> 
> Note that unlike a tuple solution, it does not cause any template bloat.
> Also doesn't have some of writefln's pitfalls (the case where a string 
> contains a % character).
> 
> Incidentally, this could do a lot better than printf, because it could 
> categorise the expressions. Eg, if there are no floating point 
> variables, it could translate it to a simple print function which 
> doesn't have the FP conversion code. Ditto for outputting arrays and 
> objects. Other optimisations are possible - eg, it could also estimate 
> how much buffer space is going to be required.
> 
> Downsides:
> (1) need to use "mixin()" until we get macros.
> (2) doesn't look like anything that's in D right now.
> (3) how are IDE's going to know when a string contains embedded variables?
> 
> Opinions? Is something like this worth considering as an alternative to 
> writefln, and to Tango's C# formatting and whisper syntax?