Re: Inconsistent placement of the keywords 'typename' and 'template'
Seungbeom Kim <musiphil@bawi.org> writes:
template <typename T1> struct test_type
{
typedef int type_name;
template <typename T2> static void template_func();
};
template <typename T> void call_test()
{
// ________
typename test_type<T>::type_name var;
// ________
test_type<T>::template template_func<int>();
}
So, 'typename' comes before the qualified name, while 'template'
intervenes into the qualified name, even though both of them serve the
same purpose of helping the compiler resolve the syntactic ambiguity.
Would anyone care to explain why we have this inconsistency?
Consider
template <typename T1> struct S1
{
template <typename T2> struct S2
{
template <typename T3> struct S3
{
typedef int Int;
};
};
};
template <typename T> void f()
{
typename S1<T>::template S2<T>::template S3<T>::Int i;
}
typename affects the entire qualified name, while template affects the
unqualified name in the respective scope, which means that it can
occur more than once within the same name; the syntax must provide for
a way to indicate what template refers to.
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