Re: Template function that accept strings and array of strings

[Vlad Levenfeld via Digitalmars-d-learn]

On Wednesday, 15 July 2015 at 21:57:50 UTC, 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 ?

T is already a type, so typeof(T) is an error, which makes the 
constraint fail.

Try
hasItemParent(T)(const(char)[] itemId, const(T)[] parentId)
if (is(T == char) || is (T == char[]))

at least I think that's what you meant. typeof(anything[]) will 
never == char.