shared and getParameterStorageClasses bug?
Sun Aug 23 21:14:38 UTC 2020
On Sunday, 23 August 2020 at 13:44:30 UTC, Jean-Louis Leroy wrote:
> On Sunday, 23 August 2020 at 06:42:02 UTC, Petar Kirov
> [ZombineDev] wrote:
>> From a grammar point of view, type qualifiers (`const`,
>> `immutable`, `inout` and `shared`) can appear as 4 different
>> 1. Type constructors 
>> 2. Variable storage classes 
>> 3. Parameter attributes 
>> 4. Member function attributes 
>> Parameter attributes grammatically include both UDAs and
>> parameter storage classes (confusingly named `InOut` in the
>> spec), so we can actually collapse the grammatical entities
>> related to variables (which include parameters) to just 2
>> kinds: type constructors and storage classes.
>> Q T x; // A) storage class syntax
>> Q(T) x; // B) type constructor syntax
>> A) and B) are equivalent (where `Q` is some type qualifier and
>> `T` is some type).
> Thanks. Then my follow-up question is: how do I retrieve the
> parameter type constructors? Without resorting on scanning the
> stringified parameter like here:
> enum isSharedParameter(alias fun, uint param) =
> Parameters!fun[param..param+1].stringof.indexOf("shared") !=
> (of course this is not robust: it would give false positives
> with types that contain the substring "shared").
> My actual goal is to extract them in the same fashion as the
> storage classes, e.g.:
> void foo(lazy const shared Object);
> static assert(parameterTypeConstructors!foo == tuple("const",
> Do I really have to parse a string like "(lazy
> shared(const(Object)))"? And, how reliable would this solution
Hmm, why do you need to extract them in the same fashion? For use
in string mixins? If you just want to create a proxy function
then simply using std.traits.Parameters should do the trick.
If you're writing a meta programming library, then perhaps you
can consider representing function types as:
1. AliasSeq of the types
2. AliasSeq of the types
3. AliasSeq of the default values
4. AliasSeq of ints, each representing a bitset of the parameter
storage classes that we're set. Or alternatively string.
Another way would be to create a Parameter struct template that
contains the relevant information and then have an AliasSeq of
Parameter types for each function type.
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