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Move MostDerived and DerivedToFront to std.traits

Browse source 
Those two helpers are about type introspection and use
MetaList only coincidently. Such utilities are better fit
to std.traits
This commit is contained in:
Dicebot 2015-03-31 00:11:02 +03:00
parent 5cd03d229a
commit 3ca20b5ca4
2 changed files with 65 additions and 51 deletions
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56
std/meta/package.d
View file

@ -37,56 +37,10 @@ public import std.meta.predicates;
// shouldn't go into release
public import std.meta.internal;
/**
* Returns the type from TList that is the most derived from type T.
* If none are found, T is returned.
*/
template MostDerived(T, TList...)
{
static if (TList.length == 0)
alias MostDerived = T;
else static if (is(TList[0] : T))
alias MostDerived = MostDerived!(TList[0], TList[1 .. $]);
else
alias MostDerived = MostDerived!(T, TList[1 .. $]);
}
static import std.traits;
///
unittest
{
class A { }
class B : A { }
class C : B { }
alias Types = MetaList!(A, C, B);
deprecated("Use std.traits.MostDerived instead")
alias MostDerived = std.traits.MostDerived;
MostDerived!(Object, Types) x; // x is declared as type C
static assert(is(typeof(x) == C));
}
/**
* Returns the list TList with the types sorted so that the most
* derived types come first.
*/
template DerivedToFront(TList...)
{
static if (TList.length == 0)
alias DerivedToFront = TList;
else
alias DerivedToFront =
MetaList!(MostDerived!(TList[0], TList[1 .. $]),
DerivedToFront!(ReplaceAll!(MostDerived!(TList[0], TList[1 .. $]),
TList[0],
TList[1 .. $])));
}
///
unittest
{
class A { }
class B : A { }
class C : B { }
alias Types = MetaList!(A, C, B);
alias TL = DerivedToFront!(Types);
static assert(is(TL == MetaList!(C, B, A)));
}
deprecated("Use std.traits.DerivedToFront instead")
alias DerivedToFront = std.traits.DerivedToFront;

60
std/traits.d
View file

@ -6383,3 +6383,63 @@ unittest
static assert(is(typeof(a) == real));
static assert(is(typeof(b) == real));
}
/**
* Returns the type from type list that is the most derived from type T.
* If none are found, T is returned.
*/
template MostDerived(T, TList...)
{
static if (TList.length == 0)
alias MostDerived = T;
else static if (is(TList[0] : T))
alias MostDerived = MostDerived!(TList[0], TList[1 .. $]);
else
alias MostDerived = MostDerived!(T, TList[1 .. $]);
}
///
unittest
{
import std.meta.list;
class A { }
class B : A { }
class C : B { }
alias Types = MetaList!(A, C, B);
MostDerived!(Object, Types) x; // x is declared as type C
static assert(is(typeof(x) == C));
}
/**
* Returns the type list based on TList with the types sorted so that
* the most derived types come first.
*/
template DerivedToFront(TList...)
{
import std.meta.list;
static if (TList.length == 0)
alias DerivedToFront = TList;
else
alias DerivedToFront =
MetaList!(MostDerived!(TList[0], TList[1 .. $]),
DerivedToFront!(ReplaceAll!(MostDerived!(TList[0], TList[1 .. $]),
TList[0],
TList[1 .. $])));
}
///
unittest
{
import std.meta.list;
class A { }
class B : A { }
class C : B { }
alias Types = MetaList!(A, C, B);
alias TL = DerivedToFront!(Types);
static assert(is(TL == MetaList!(C, B, A)));
}