Re: How to list all the manifest constants in a class or struct
On Sunday, 17 June 2018 at 20:03:09 UTC, aliak wrote:
On Sunday, 17 June 2018 at 02:44:38 UTC, Heromyth wrote:
[...]
I think this bolts.isManifestAssignable [1] will get you
partially there. The place where it'll fail though is a static
immutable (since they are assignable to manifest constants) but
you can filter those by seeing if you can take the address,
something like:
foreach (m; __traits(allMembers, T)) {
if (isManifestAssignable!(T, m) &&
!is(typeof(mixin(""~m))) {
// it's a manifest constant ... (?)
}
}
There of course might be edge cases I can't think of/don't know
about though.
Cheers,
- Ali
http://bolts.dpldocs.info/bolts.traits.isManifestAssignable.html
Thant's it. Thanks for your great lib:
https://github.com/aliak00/bolts
Re: How to list all the manifest constants in a class or struct
On Sunday, 17 June 2018 at 02:44:38 UTC, Heromyth wrote:
Here is a struct named S:
struct S
{
enum X = 10;
enum Y
{
i = 10
}
enum Z = "str";
struct S {}
class C {}
static int sx = 0;
__gshared int gx = 0;
shared void g();
}
I want list all then the manifest constants in it.
I searched the std.traits and this forums, but get nothing.
Maybe, my real question is how to get the storage class for a
member in a class or struct.
Thanks.
I think this bolts.isManifestAssignable [1] will get you
partially there. The place where it'll fail though is a static
immutable (since they are assignable to manifest constants) but
you can filter those by seeing if you can take the address,
something like:
foreach (m; __traits(allMembers, T)) {
if (isManifestAssignable!(T, m) && !is(typeof(mixin(""~m))) {
// it's a manifest constant ... (?)
}
}
There of course might be edge cases I can't think of/don't know
about though.
Cheers,
- Ali
http://bolts.dpldocs.info/bolts.traits.isManifestAssignable.html
Re: How to list all the manifest constants in a class or struct
On Sunday, 17 June 2018 at 04:32:29 UTC, Jonathan M Davis wrote:
On Sunday, June 17, 2018 02:44:38 Heromyth via
Digitalmars-d-learn wrote:
Here is a struct named S:
struct S
{
enum X = 10;
enum Y
{
i = 10
}
enum Z = "str";
struct S {}
class C {}
static int sx = 0;
__gshared int gx = 0;
shared void g();
}
I want list all then the manifest constants in it.
I searched the std.traits and this forums, but get nothing.
Maybe, my real question is how to get the storage class for a
member in a class or struct.
As the storage class isn't part of the type, type introspection
tends to ignore it. You'll basically have to get the full list
of members of the type and then filter out stuff that isn't a
manifest constant, which is not exactly pleasant and can get a
bit tricky but should be possible. You'll probably have to do
something like filter out all of the members where you can take
their address and filter out all of the ones that are types,
and and at that point, you'd be close, but I'd have to
experiment to figure out whether that was enough or not or
whether something crept through.
Andrei has been working on coming up with a better wrapper
around the current introspection stuff so that you'll actually
get data types which contain the information about a symbol
rather than having to figure out which combination of __traits
and traits from std.traits are required to get what you want.
So, I expect that stuff like this will get a lot easier once
that's ready, but in the interim, if you're trying to do
something less common, it can involve having to do a lot clever
filtering to get exactly the stuff you want and only the stuff
you want - and I don't think that getting the list of manifest
constants in a type is a very typical thing for folks to do, so
std.traits certainly doesn't have anything like
isManifestConstant.
- Jonathan M Davis
Thanks for your answers. It's so glad to see some works have been
taken for this.
The isManifestConstant is really necessary. For example, I want
to port an Enum type from Java to D. It seems better to use a
Struct instead of an Enum.
See here:
https://github.com/eclipse/jetty.project/blob/jetty-9.4.x/jetty-http/src/main/java/org/eclipse/jetty/http/HttpStatus.java
https://github.com/eclipse/jetty.project/blob/jetty-9.4.x/jetty-http/src/main/java/org/eclipse/jetty/http/HttpHeaderValue.java
Of course, I can define a enum for members with the basic types
in D.
Sometimes, I like to define them in a class or struct as manifest
constants or immutable ones. So, I need isManifestConstant.
Re: How to list all the manifest constants in a class or struct
On Sunday, June 17, 2018 02:44:38 Heromyth via Digitalmars-d-learn wrote:
> Here is a struct named S:
>
> struct S
> {
> enum X = 10;
> enum Y
> {
> i = 10
> }
> enum Z = "str";
> struct S {}
> class C {}
>
> static int sx = 0;
> __gshared int gx = 0;
>
> shared void g();
> }
>
> I want list all then the manifest constants in it.
>
> I searched the std.traits and this forums, but get nothing.
> Maybe, my real question is how to get the storage class for a
> member in a class or struct.
As the storage class isn't part of the type, type introspection tends to
ignore it. You'll basically have to get the full list of members of the type
and then filter out stuff that isn't a manifest constant, which is not
exactly pleasant and can get a bit tricky but should be possible. You'll
probably have to do something like filter out all of the members where you
can take their address and filter out all of the ones that are types, and
and at that point, you'd be close, but I'd have to experiment to figure out
whether that was enough or not or whether something crept through.
Andrei has been working on coming up with a better wrapper around the
current introspection stuff so that you'll actually get data types which
contain the information about a symbol rather than having to figure out
which combination of __traits and traits from std.traits are required to get
what you want. So, I expect that stuff like this will get a lot easier once
that's ready, but in the interim, if you're trying to do something less
common, it can involve having to do a lot clever filtering to get exactly
the stuff you want and only the stuff you want - and I don't think that
getting the list of manifest constants in a type is a very typical thing for
folks to do, so std.traits certainly doesn't have anything like
isManifestConstant.
- Jonathan M Davis
How to list all the manifest constants in a class or struct
Here is a struct named S:
struct S
{
enum X = 10;
enum Y
{
i = 10
}
enum Z = "str";
struct S {}
class C {}
static int sx = 0;
__gshared int gx = 0;
shared void g();
}
I want list all then the manifest constants in it.
I searched the std.traits and this forums, but get nothing.
Maybe, my real question is how to get the storage class for a
member in a class or struct.
Thanks.
