Re: typeof.stringof wrong type
On Friday, 19 August 2016 at 18:52:02 UTC, Jonathan M Davis wrote: Unfortunately, once you start doing stuff with things like __traits(allMembers, ...), you're dealing with strings You should immediately go back into symbol land by passing that string into __traits(getMember). I agree that stringof is almost always a bug, if not ALWAYS a bug, when seen in code generator. There's better ways.
Re: typeof.stringof wrong type
On Friday, 19 August 2016 at 15:47:00 UTC, ag0aep6g wrote: https://dlang.org/spec/property.html#stringof Someone should edit that, if fullyQualifiedName is no good either. Indeed. I'm sure the change was well-intentioned, but symbol visibility/import concerns and Voldemort types should make it abundantly clear that this can't work ever work in the general case. — David
Re: typeof.stringof wrong type
On 08/19/2016 05:36 PM, David Nadlinger wrote: This is a misconception. Neither .stringof nor fullyQualifiedName should *ever* be used in code generation. The spec itself recommends fullyQualifiedName for code generation: Note: Using .stringof for code generation is not recommended, as the internal representation of a type or expression can change between different compiler versions. Instead you should prefer to use the identifier trait, or one of the Phobos helper functions such as fullyQualifiedName. https://dlang.org/spec/property.html#stringof Someone should edit that, if fullyQualifiedName is no good either.
Re: typeof.stringof wrong type
On Friday, 19 August 2016 at 15:15:55 UTC, ag0aep6g wrote:
I think that qualifies as a bug, because fullyQualifiedName is
supposed to be usable in code generation.
This is a misconception. Neither .stringof nor fullyQualifiedName
should *ever* be used in code generation. There is a myriad of
things that make strings unsuitable in the general case. The most
obvious reason are imports: think a type coming via an alias
parameter from a second module, which is not even important at
the point of the mixin.
Instead of trying to make .stringof work do things it will never
be able to, you need to use the type just as you would at the
point of the mixin. In this example, you would write
`mixin("typeof(a) d");`.
— David
Re: typeof.stringof wrong type
fullyQualifiedName doesn't work with BitFlags for example:
import std.stdio;
import std.typecons;
import std.traits;
enum Stuff
{
asdf
}
void main()
{
BitFlags!Stuff a;
typeof(a) b;
mixin(fullyQualifiedName!(typeof(a)) ~ " c;");
mixin(typeof(a).stringof ~ " d;");
}
Both mixins fail. fullyQualifiedName!(typeof(a)) becomes:
std.typecons.BitFlags!(test.Stuff, cast(Flag)false)
"cast(Flag)false" should be "cast(Flag!"unsafe")false". So string
template parameter "unsafe" is missing. The same problem as I
described before ("Flag" is an enum template like in my first
example).
Re: typeof.stringof wrong type
On Wednesday, 17 August 2016 at 12:39:18 UTC, ag0aep6g wrote:
On 08/17/2016 02:08 PM, Eugene Wissner wrote:
I have a problem, that .stringof doesn't return what I'm
expecting.
Consider the following:
template A(string T)
{
enum A : bool
{
yes = true,
}
}
void main()
{
A!"asdf" a1;
typeof(a1) a2;
mixin(typeof(a1).stringof ~ " a3;");
}
I get an error: some.d-mixin-13|13 error| Error: template
some.A(string
T) is used as a type
Why the second line in main() works but the third one not?
typeof(a1).stringof seems to ignore the string template
parameter T.
pragma(msg, typeof(a1).stringof) would return just "A".
Is it a bug?
Not exactly a bug. .stringof gives you a simple, readable name.
It's not meant to be used in code generation. You can use
std.traits.fullyQualifiedName instead:
import std.traits: fullyQualifiedName;
mixin(fullyQualifiedName!(typeof(a1)) ~ " a3;");
What I find strange is that if A isn't a enum, but a class the
.stringof returns the full type name, therefore I would expect it
behave the same in the code above.
I will test later fullyQualifiedName, the example above is very
simplified version of the code I had problem with. Thanks anyway
Re: typeof.stringof wrong type
On 08/17/2016 02:08 PM, Eugene Wissner wrote:
I have a problem, that .stringof doesn't return what I'm expecting.
Consider the following:
template A(string T)
{
enum A : bool
{
yes = true,
}
}
void main()
{
A!"asdf" a1;
typeof(a1) a2;
mixin(typeof(a1).stringof ~ " a3;");
}
I get an error: some.d-mixin-13|13 error| Error: template some.A(string
T) is used as a type
Why the second line in main() works but the third one not?
typeof(a1).stringof seems to ignore the string template parameter T.
pragma(msg, typeof(a1).stringof) would return just "A".
Is it a bug?
Not exactly a bug. .stringof gives you a simple, readable name. It's not
meant to be used in code generation. You can use
std.traits.fullyQualifiedName instead:
import std.traits: fullyQualifiedName;
mixin(fullyQualifiedName!(typeof(a1)) ~ " a3;");
