Where are we with thoughts on string interpolation and mixins?

[aliak]

On Tuesday, 20 November 2018 at 10:09:40 UTC, Zoadian wrote:
> On Tuesday, 20 November 2018 at 09:19:41 UTC, aliak wrote:
>> Hello,
>>
>> I do a lot of work with mixins. But, it's usually very hard to 
>> read, and therefore reason about, and therefor review, and 
>> therefor maintain. So I'm wondering what people's thoughts are 
>> on how we can improve the experience of using mixins.
>>
>> [...]
>
> While I do agree that string interp would be nice, I think it 
> could be done in library code. Let me show you how I currently 
> do something like it:
>
> ```
> private enum LIQUID_ASGRAM_DEFINE_API(string PRE, T, TC, TI) = `
> 	struct %PRE%_s;
> 	alias %PRE% = %PRE%_s*;
> 	%PRE% %PRE%_create(uint nfft);
> 	void %PRE%_destroy(%PRE% q);
> 	void %PRE%_reset(%PRE% q);
> 	void %PRE%_set_scale(%PRE% q, float ref_lvl, float div);
> 	void %PRE%_set_display(%PRE% q, const(char)* ascii);
> 	void %PRE%_push(%PRE% q, %TI% x);
> 	void %PRE%_write(%PRE% q, %TI%* x, uint n);
> 	void %PRE%_execute(%PRE% q, char*  ascii, float * peakval, 
> float * peakfreq);
> 	void %PRE%_print(%PRE% q);
> `.replace("%PRE%", PRE).replace("%T%", 
> T.stringof).replace("%TC%", TC.stringof).replace("%TI%", 
> TI.stringof);
>
> mixin(LIQUID_ASGRAM_DEFINE_API!("asgramcf", float, 
> liquid_float_complex, liquid_float_complex));
>
> mixin(LIQUID_ASGRAM_DEFINE_API!("asgramf", float, 
> liquid_float_complex, float));
> ```

You almost prove some of the same points I'm trying to make :p

"replace("%T%", T.stringof).replace("%TC%", TC.stringof)"

Are not needed as %T%  and %TC% are not in that string.

And probably all the places you call LIQUID_ASGRAM_DEFINE_API 
have extra arguments that negatively impact any kind of code 
reviews. And this would happen constantly. Code evolves, so 
people will change LIQUID_ASGRAM_DEFINE_API and review it, and 
debug it.

But on a side note, I do think that in some cases a .format() 
would be a lot more readable than string interop, especially 
where you are reusing one variable a lot of times. Like in your 
example:

private enum LIQUID_ASGRAM_DEFINE_API(string PRE, T, TC, TI) = `
	struct %1_s;
	alias %1 = %1_s*;
	%1 %1_create(uint nfft);
	void %1_destroy(%1 q);
	void %1_reset(%1 q);
	void %1_set_scale(%1 q, float ref_lvl, float div);
	void %1_set_display(%1 q, const(char)* ascii);
	void %1_push(%1 q, %2 x);
	void %1_write(%1 q, %2* x, uint n);
	void %1_execute(%1 q, char*  ascii, float * peakval, float * 
peakfreq);
	void %1_print(%1 q);
`.format(PRE, TI.stringof);

Though, as the number of placeholders increase, so does your 
mental burden.

Cheer,
- Ali