Re: How to check if string is available at compile time

[Meta via Digitalmars-d-learn]

On Thursday, 21 September 2017 at 12:30:15 UTC, David Bennett 
wrote:
On Thursday, 21 September 2017 at 11:42:36 UTC, David Bennett 
wrote:
[snip]

```
string[] escapeCTFE(Args...)(){
    static foreach (arg; Args){
        static if(__traits(compiles, ###WHATDOIPUTHERE###)){
[snip]


So far the best I've come up with is :

```

enum isCTstring(alias arg) = (!isAssignable!(typeof(arg)) || 
__traits(compiles, mixin(` "foo" ~ `~__traits(identifier, 
arg))));

string[] escapeCTFE(Args...)(){

    static foreach (arg; Args){
        static if(isCTstring!(arg)){
            pragma(msg, "Do work on string: ", arg);
        }else{
            pragma(msg, __traits(identifier, arg), " can only 
be read at runtime");
        }
    }
    return new string[32];
}

```

But this seems quite hackish... any better ideas?

Try __traits(compiles, { enum _ = arg; }). Creating an enum 
necessarily requires that its value is available at compile time.