On Friday, 11 April 2014 at 14:05:17 UTC, Vlad Levenfeld wrote:
I'm trying to cut down on some boilerplate with this function:
const string link (alias variable) ()
{
const string name = __traits (identifier, variable);
return name~`= glGetUniformLocation (program, "`~name~`");`;
}
Applied in this kind of context:
this ()
{
super ("default.vert", "gradient.frag");
mixin link!start_color;
mixin link!final_color;
mixin link!center_pos;
mixin link!lerp_vec;
mixin link!lerp_range;
}
And the first mixin in every such function works fine, but the
rest don't. Specifically, I get this error:
source/main.d(483): Error: mixin link!final_color link isn't a
template
for each mixin after the first. If I put the argument to mixin
in parenthesis:
mixin (link!start_color);
I get:
source/main.d(483): Error: value of 'this' is not known at
compile time
Finally, removing the parenthesis and putting each mixin
statement in its own block:
{mixin link!start_color;}
compiles, but the mixed-in string has no apparent effect.
Is this a bug or am I doing it wrong?
I'm not sure exactly what's going on here, but here's a few bits
of info you might find useful.
mixin mixinTemplate!Params;
is for template mixins http://dlang.org/template-mixin.html
mixin(someString);
is for string mixins http://dlang.org/mixin.html
template mixins can only insert declarations/definitions, string
mixins can inject arbitrary code i.e. anything.
When working with string mixins, pragma(msg allows you to print
the result at compile-time to check what code is being generated.
http://dlang.org/pragma.html
