Add meta.trait.Fields

This commit is contained in:
Eugen Wissner 2017-10-27 20:28:34 +02:00
parent 0d69c7fc79
commit 414d7a11a8

View File

@ -1758,6 +1758,10 @@ template isMutable(T)
} }
/** /**
* Determines whether $(D_PARAM T) is a nested type, i.e. $(D_KEYWORD class),
* $(D_KEYWORD struct) or $(D_KEYWORD union), which internally stores a context
* pointer.
*
* Params: * Params:
* T = $(D_KEYWORD class), $(D_KEYWORD struct) or $(D_KEYWORD union) type. * T = $(D_KEYWORD class), $(D_KEYWORD struct) or $(D_KEYWORD union) type.
* *
@ -1788,6 +1792,8 @@ pure nothrow @safe unittest
} }
/** /**
* Determines whether $(D_PARAM T) is a nested function.
*
* Params: * Params:
* F = A function. * F = A function.
* *
@ -1809,6 +1815,8 @@ enum bool isNestedFunction(alias F) = __traits(isNested, F);
} }
/** /**
* Determines the type of the callable $(D_PARAM F).
*
* Params: * Params:
* F = A function. * F = A function.
* *
@ -1898,6 +1906,8 @@ if (isCallable!F)
} }
/** /**
* Determines the return type of the callable $(D_PARAM F).
*
* Params: * Params:
* F = A callable object. * F = A callable object.
* *
@ -3055,3 +3065,60 @@ template isInnerClass(T)
} }
static assert(!isInnerClass!(RefCountedStore!int)); static assert(!isInnerClass!(RefCountedStore!int));
} }
/**
* Returns the types of all members of $(D_PARAM T).
*
* If $(D_PARAM T) is a $(D_KEYWORD struct) or $(D_KEYWORD union) or
* $(D_KEYWORD class), returns the types of all its fields. It is actually the
* same as `T.tupleof`, but the content pointer for the nested type isn't
* included.
*
* If $(D_PARAM T) is neither a $(D_KEYWORD struct) nor $(D_KEYWORD union) nor
* $(D_KEYWORD class), $(D_PSYMBOL Fields) returns an $(D_PSYMBOL AliasSeq)
* with the single element $(D_PARAM T).
*
* Params:
* T = A type.
*
* Returns: $(D_PARAM T)'s fields.
*/
template Fields(T)
{
static if ((is(T == struct) || is(T == union)) && isNested!T)
{
// The last element of .tupleof of a nested struct or union is "this",
// the context pointer, type "void*".
alias Fields = typeof(T.tupleof[0 .. $ - 1]);
}
else static if (is(T == class) || is(T == struct) || is(T == union))
{
alias Fields = typeof(T.tupleof);
}
else
{
alias Fields = AliasSeq!T;
}
}
///
@nogc nothrow pure @safe unittest
{
struct Nested
{
int i;
void func()
{
}
}
static assert(is(Fields!Nested == AliasSeq!int));
class C
{
uint u;
}
static assert(is(Fields!C == AliasSeq!uint));
static assert(is(Fields!short == AliasSeq!short));
}