optimatization suggestion

[H. S. Teoh via Digitalmars-d]

On Sat, Apr 01, 2017 at 05:15:54PM +0000, Inquie via Digitalmars-d wrote:
> I use a lot of code that has string appending and it seems like it could be
> optimized;
> 
> wchar[] x;
> 
> x ~= "This is one line";
> x ~= "This is another line";

You could have just written instead:

	wchar[] x;
	x ~= "This is one line" ~
	     "This is another line";

?


[...]
> More complex cases could be handled such as
> 
> x ~= "This is one"~x~" line";
> x ~= "This is another line";
> 
> which turns in to
> 
> x ~= "This is one"~x~" lineThis is another line";
> 
> Since these are done in ctfe, it may improve the speed significantly
> in some cases!? (usually the splitting up is for readability and to
> allow for easy modification)

If you want something done in CTFE, do this:

	string makeLongString()
	{
		wchar[] x;
		x ~= "blahblah";
		x ~= "blehbleh";
		x ~= "abc " ~ x ~ " def";
		return x;
	}

	void main() {
		enum e = makeLongString(); // enum forces CTFE
		string x = e;		// voila, everything done at compile-time
	}


T

-- 
"Real programmers can write assembly code in any language. :-)" -- Larry Wall