Re: Checking for manifest constants
On Friday, 5 March 2021 at 14:42:07 UTC, Petar Kirov [ZombineDev]
wrote:
On Friday, 5 March 2021 at 08:23:09 UTC, Bogdan wrote:
[...]
I suggest this:
enum globalConfig = 32;
int globalValue = 22;
immutable globaImmutablelValue = 22;
enum isManifestConstant(alias symbol) =
__traits(compiles, { enum e = symbol; }) &&
!__traits(compiles, { const ptr = });
unittest {
struct Test {
enum config = 3;
int value = 2;
}
static assert(isManifestConstant!(Test.config));
static assert(isManifestConstant!(mixin("Test.config")));
static assert(isManifestConstant!(globalConfig));
static assert(isManifestConstant!(mixin("globalConfig")));
static assert(!isManifestConstant!(Test.value));
static assert(!isManifestConstant!(mixin("Test.value")));
static assert(!isManifestConstant!(globalValue));
static assert(!isManifestConstant!(mixin("globalValue")));
static assert(!isManifestConstant!(globaImmutablelValue));
static
assert(!isManifestConstant!(mixin("globaImmutablelValue")));
}
Thanks!
I ended using this:
```
/// Check if a member is manifest constant
enum isManifestConstant(T, string name) =
isManifestConstant!(__traits(getMember, T, name));
/// ditto
enum isManifestConstant(alias symbol) = __traits(compiles, { enum
e = symbol; }) &&
!__traits(compiles, { const ptr = });
```
It looks like mixin does not work well with protected/private
members
Re: Checking for manifest constants
On Friday, 5 March 2021 at 08:23:09 UTC, Bogdan wrote:
I was using a trick with dmd to check for manifest constants
which worked until dmd v2.094. Yesterday I tried it on the
latest compiler and it failed with:
source/introspection/manifestConstant.d(37,28): Error: need
this for name of type string
source/introspection/type.d(156,13): Error: value of this is
not known at compile time
any ideas how to fix it? or, is it a bug with dmd?
```
/// Check if a member is manifest constant
bool isManifestConstant(T, string name)() {
mixin(`return is(typeof(T.init.` ~ name ~ `)) &&
!is(typeof(` ~ name ~ `));`);
}
/// ditto
bool isManifestConstant(alias T)() {
return is(typeof(T)) && !is(typeof());
}
enum globalConfig = 32;
int globalValue = 22;
unittest {
struct Test {
enum config = 3;
int value = 2;
}
static assert(isManifestConstant!(Test.config));
static assert(isManifestConstant!(Test, "config"));
static assert(isManifestConstant!(globalConfig));
static assert(!isManifestConstant!(Test.value));
static assert(!isManifestConstant!(Test, "value"));
static assert(!isManifestConstant!(globalValue));
}
void main() {}
```
I suggest this:
enum globalConfig = 32;
int globalValue = 22;
immutable globaImmutablelValue = 22;
enum isManifestConstant(alias symbol) =
__traits(compiles, { enum e = symbol; }) &&
!__traits(compiles, { const ptr = });
unittest {
struct Test {
enum config = 3;
int value = 2;
}
static assert(isManifestConstant!(Test.config));
static assert(isManifestConstant!(mixin("Test.config")));
static assert(isManifestConstant!(globalConfig));
static assert(isManifestConstant!(mixin("globalConfig")));
static assert(!isManifestConstant!(Test.value));
static assert(!isManifestConstant!(mixin("Test.value")));
static assert(!isManifestConstant!(globalValue));
static assert(!isManifestConstant!(mixin("globalValue")));
static assert(!isManifestConstant!(globaImmutablelValue));
static
assert(!isManifestConstant!(mixin("globaImmutablelValue")));
}
Re: Checking for manifest constants
On Friday, 5 March 2021 at 08:23:09 UTC, Bogdan wrote:
I was using a trick with dmd to check for manifest constants
which worked until dmd v2.094. Yesterday I tried it on the
latest compiler and it failed with:
source/introspection/manifestConstant.d(37,28): Error: need
this for name of type string
source/introspection/type.d(156,13): Error: value of this is
not known at compile time
any ideas how to fix it? or, is it a bug with dmd?
```
/// Check if a member is manifest constant
bool isManifestConstant(T, string name)() {
mixin(`return is(typeof(T.init.` ~ name ~ `)) &&
!is(typeof(` ~ name ~ `));`);
}
/// ditto
bool isManifestConstant(alias T)() {
return is(typeof(T)) && !is(typeof());
}
enum globalConfig = 32;
int globalValue = 22;
unittest {
struct Test {
enum config = 3;
int value = 2;
}
static assert(isManifestConstant!(Test.config));
static assert(isManifestConstant!(Test, "config"));
static assert(isManifestConstant!(globalConfig));
static assert(!isManifestConstant!(Test.value));
static assert(!isManifestConstant!(Test, "value"));
static assert(!isManifestConstant!(globalValue));
}
void main() {}
```
Hello, you can use this template instead:
template isManifestConstant(alias V, T...)
if (T.length == 0 || (T.length == 1 && is(T[0])))
{
enum isKnown = is(typeof((){enum v = V;}));
static if (!T.length)
enum isManifestConstant = isKnown;
else
enum isManifestConstant = isKnown && is(typeof(V) ==
T[0]);
}
The optional T is to verify if it is a compile time constant of a
certain type.
the tests you wrote and that are not based on a string pass.
Checking for manifest constants
I was using a trick with dmd to check for manifest constants
which worked until dmd v2.094. Yesterday I tried it on the latest
compiler and it failed with:
source/introspection/manifestConstant.d(37,28): Error: need this
for name of type string
source/introspection/type.d(156,13): Error: value of this is not
known at compile time
any ideas how to fix it? or, is it a bug with dmd?
```
/// Check if a member is manifest constant
bool isManifestConstant(T, string name)() {
mixin(`return is(typeof(T.init.` ~ name ~ `)) &&
!is(typeof(` ~ name ~ `));`);
}
/// ditto
bool isManifestConstant(alias T)() {
return is(typeof(T)) && !is(typeof());
}
enum globalConfig = 32;
int globalValue = 22;
unittest {
struct Test {
enum config = 3;
int value = 2;
}
static assert(isManifestConstant!(Test.config));
static assert(isManifestConstant!(Test, "config"));
static assert(isManifestConstant!(globalConfig));
static assert(!isManifestConstant!(Test.value));
static assert(!isManifestConstant!(Test, "value"));
static assert(!isManifestConstant!(globalValue));
}
void main() {}
```
