Template variable not reach at compile

Greatsam4sure greatsam4sure at gmail.com
Sat Jul 21 13:59:20 UTC 2018


On Saturday, 21 July 2018 at 13:13:11 UTC, Mike Parker wrote:
> On Saturday, 21 July 2018 at 12:17:54 UTC, Greatsam4sure wrote:
>> Sorry for the typo.  This is the problem
>>
>> auto arithmetic(T, V, U)(T a,  V b,  U op){
>>    return mixin("a"~op~"b");
>> }
>>
>> //call like this
>> arithmetic(1.5,2.5,"+");
>>
>>
>> Compiler says the variable op is not reach at compile time.  
>> So how can the varible a and b be reach at compile time and op 
>> is not reach. I will appreciate any help. I have also use a 
>> static if but the same complain.  Just a newbie in D
>
> You aren't using a or b at compile time -- you're using the 
> string literals "a" and "b", which have nothing at all to do 
> with a and b. In order to get what you want, you need to make 
> op a template parameter like this:
>
> auto arithmetic(string op, T, V)(T a, V b)
> {
>     mixin("a"~op~"b");
> }
>
> arithmetic!("+")(1.5, 2.5);


Thanks Sir.  Really appreciate your reply it works for me. I also 
want to thank you for all your labour in the dlang ecosystem or 
foundation. I read about the dlang announce group every day. I 
will also want update to dlang this week or close it down or 
redirect to the announce group directly



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