Re: get parameter names
On Friday, 1 September 2017 at 22:21:18 UTC, Biotronic wrote:
On Friday, 1 September 2017 at 20:58:20 UTC, EntangledQuanta
wrote:
template(A, B...)
{
auto foo(C...)(C c)
{
... get c's parameter names, should be alpha, beta
}
}
foo!(., .)(alpha, beta)
I need the actual identifiers passed to foo. I can get the
types(obviously C) but when I try to get the identifier
names(__traits(identifier or other methods) I stuff get
_param_k or errors.
I need both C's types and the parameter identifier names past,
else I'd just pass as strings.
Like Jonathan M Davis points out, this is impossible for
regular parameters. For template alias parameters, on the other
hand, this works:
void bar(alias fn)() {
assert(fn.stringof == "alpha");
}
unittest {
int alpha;
bar!(alpha);
}
--
Biotronic
The problem I have with this is that when I try to pass variables
in the template complains that there is no "this"
So, what I have resorted to doing is passing the type and the
name, which seems redundant:
bar!(int, "alpha")
rather than
bar!(alpha) or bar(alpha)
alpha is a variable in a object in my case.
I've tried basically something like the following
void bar(alias fn)()
{
typeof(fn) should return int and
fn.stringof should return "alpha"
}
although my code is more complex since I have multiple template
parameters(using a variadic).
Re: get parameter names
On Friday, 1 September 2017 at 20:58:20 UTC, EntangledQuanta
wrote:
template(A, B...)
{
auto foo(C...)(C c)
{
... get c's parameter names, should be alpha, beta
}
}
foo!(., .)(alpha, beta)
I need the actual identifiers passed to foo. I can get the
types(obviously C) but when I try to get the identifier
names(__traits(identifier or other methods) I stuff get
_param_k or errors.
I need both C's types and the parameter identifier names past,
else I'd just pass as strings.
Like Jonathan M Davis points out, this is impossible for regular
parameters. For template alias parameters, on the other hand,
this works:
void bar(alias fn)() {
assert(fn.stringof == "alpha");
}
unittest {
int alpha;
bar!(alpha);
}
--
Biotronic
Re: get parameter names
On Friday, September 01, 2017 20:58:20 EntangledQuanta via Digitalmars-d-
learn wrote:
> template(A, B...)
> {
> auto foo(C...)(C c)
> {
> ... get c's parameter names, should be alpha, beta
> }
> }
>
>
> foo!(., .)(alpha, beta)
>
> I need the actual identifiers passed to foo. I can get the
> types(obviously C) but when I try to get the identifier
> names(__traits(identifier or other methods) I stuff get _param_k
> or errors.
>
> I need both C's types and the parameter identifier names past,
> else I'd just pass as strings.
Those would actually be the arguments, not the parameters (c would be the
parameters), but regardless, there's no way to do that. The function being
called knows nothing about the caller. The only case that's even vaguely
like that are the __FILE__ and __LINE__ directives which evaluate at the
call site rather at the declaration site if they're used to default
initialize a parameter (whereas in C++, they evaluate at the declaration
site, which is a lot less useful). The function knows what its parameters
are, but it knows nothing about what the arguments that were used to
initialize the parameters were.
If you want the names of the arguments to be passed to the function, you're
going to have to pass them yourself.
- Jonathan M Davis
get parameter names
template(A, B...)
{
auto foo(C...)(C c)
{
... get c's parameter names, should be alpha, beta
}
}
foo!(., .)(alpha, beta)
I need the actual identifiers passed to foo. I can get the
types(obviously C) but when I try to get the identifier
names(__traits(identifier or other methods) I stuff get _param_k
or errors.
I need both C's types and the parameter identifier names past,
else I'd just pass as strings.
