Nick Sabalausky wrote:
"bearophile" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
Steven Schveighoffer:
lol!!!
I know, I know... :-) But when people do errors so often, the error is
elsewhere, in the original choice of that word to denote how many items an
iterable has.
In my libs I have defined len() like this, that I use now and then (where
running speed isn't essential):
long len(TyItems)(TyItems items) {
static if (HasLength!(TyItems))
return items.length;
else {
long len;
// this generates: foreach (p1, p2, p3; items) len++; with a
variable number of p1, p2...
mixin("foreach (" ~ SeriesGen1!("p", ", ", OpApplyCount!(TyItems),
1) ~ "; items) len++;");
return len;
}
} // End of len(items)
/// ditto
long len(TyItems, TyFun)(TyItems items, TyFun pred) {
static assert(IsCallable!(TyFun), "len(): predicate must be a
callable");
long len;
static if (IsAA!(TyItems)) {
foreach (key, val; items)
if (pred(key, val))
len++;
} else static if (is(typeof(TyItems.opApply))) {
mixin("foreach (" ~ SeriesGen1!("p", ", ", OpApplyCount!(TyItems),
1) ~ "; items)
if (pred(" ~ SeriesGen1!("p", ", ", OpApplyCount!(TyItems), 1)
~ "))
len++;");
} else {
foreach (el; items)
if (pred(el))
len++;
}
return len;
} // End of len(items, pred)
alias len!(string) strLen; /// ditto
alias len!(int[]) intLen; /// ditto
alias len!(float[]) floatLen; /// ditto
Having a global callable like len() instead of an attribute is (sometimes)
better, because you can use it for example like this (this is working
syntax of my dlibs):
children.sort(&len!(string));
That sorts the array of strings "children" according to the given callable
key, that is the len of the strings.
If we ever get extension methods, then maybe something along these lines
would be nice:
extension typeof(T.length) len(T t)
{
return T.length;
}
Already works:
uint len(A) (in A x) { return x.length; }
