Template function that accept strings and array of strings

[Jacob Carlborg via Digitalmars-d-learn]

On 2015-07-15 23:57, badlink wrote:
> Hello, I can't figure how to write a template function that accept
> either strings or array of strings.
>
> This is my current code:
>
> bool hasItemParent(T)(const(char)[] itemId, const(T)[] parentId)
> if (is(typeof(T) == char) || (isArray!T && is(typeof(T[]) == char)))
> {...}
>
> I used const(T)[] because I'd like to accept immutable and mutable strings.
> But calling it with an immutable string generate this error:
>
> Error: template cache.MetadataCache.hasItemParent cannot deduce function
> from argument types !()(string, string), candidates are:
> cache.MetadataCache.hasItemParent(T)(const(char)[] itemId, const(T)[]
> parentId) if (is(typeof(T) == char))
>
> Any suggestions ?

If I understand you correctly, I think you want a type safe variadic 
function:

void foo (const(char[])[] args ...)
{
     writeln(args);
}

void main()
{
     foo("foo", "bar");
     foo("foo".dup, "bar".dup);
     auto a = ["foo", "bar"];
     foo(a);
     auto b = ["foo".dup, "bar".dup];
     foo(b);
}

-- 
/Jacob Carlborg