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Add templates to meta.transform

This commit is contained in:
Eugen Wissner 2017-08-14 14:13:43 +02:00
parent a5026e48d8
commit 1d91bb4df9
1 changed files with 282 additions and 3 deletions
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285
source/tanya/meta/transform.d
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@ -5,7 +5,8 @@
/**
* Type transformations.
*
* Templates in this module applied to a type produce a transformed type.
* Templates in this module can be used to modify type qualifiers or transform
* types.
*
* Copyright: Eugene Wissner 2017.
* License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
@ -16,6 +17,8 @@
*/
module tanya.meta.transform;
import tanya.meta.traits;
/**
* Removes any type qualifiers from $(D_PARAM T).
*
@ -33,6 +36,8 @@ module tanya.meta.transform;
*
* Params:
* T = A type.
*
* Returns: $(D_PARAM T) without any type qualifiers.
*/
template Unqual(T)
{
@ -66,11 +71,15 @@ pure nothrow @safe @nogc unittest
}
/**
* If $(D_PARAM T) is an $(D_KEYWORD enum), $(D_INLINECODE OriginalType!T) evaluates to the
* most base type of that $(D_KEYWORD enum) and to $(D_PARAM T) otherwise.
* If $(D_PARAM T) is an $(D_KEYWORD enum), $(D_INLINECODE OriginalType!T)
* evaluates to the most base type of that $(D_KEYWORD enum) and to
* $(D_PARAM T) otherwise.
*
* Params:
* T = A type.
*
* Returns: Base type of the $(D_KEYWORD enum) $(D_PARAM T) or $(D_PARAM T)
* itself.
*/
template OriginalType(T)
{
@ -110,3 +119,273 @@ pure nothrow @safe @nogc unittest
static assert(is(OriginalType!E4 == bool));
static assert(is(OriginalType!(const E4) == bool));
}
/**
* Copies constness of $(D_PARAM From) to $(D_PARAM To).
*
* The following type qualifiers affect the constness and hence are copied:
* $(UL
* $(LI const)
* $(LI immutable)
* $(LI inout)
* $(LI inout const)
* )
*
* Params:
* From = Source type.
* To = Target type.
*
* Returns: $(D_PARAM To) with the constness of $(D_PARAM From).
*
* See_Also: $(D_PSYMBOL CopyTypeQualifiers).
*/
template CopyConstness(From, To)
{
static if (is(From T == immutable T))
{
alias CopyConstness = immutable To;
}
else static if (is(From T == const T) || is(From T == shared const T))
{
alias CopyConstness = const To;
}
else static if (is(From T == inout T) || is(From T == shared inout T))
{
alias CopyConstness = inout To;
}
else static if (is(From T == inout const T)
|| is(From T == shared inout const T))
{
alias CopyConstness = inout const To;
}
else
{
alias CopyConstness = To;
}
}
///
pure nothrow @safe @nogc unittest
{
static assert(is(CopyConstness!(int, char) == char));
static assert(is(CopyConstness!(const int, char) == const char));
static assert(is(CopyConstness!(immutable int, char) == immutable char));
static assert(is(CopyConstness!(inout int, char) == inout char));
static assert(is(CopyConstness!(inout const int, char) == inout const char));
static assert(is(CopyConstness!(shared int, char) == char));
static assert(is(CopyConstness!(shared const int, char) == const char));
static assert(is(CopyConstness!(shared inout int, char) == inout char));
static assert(is(CopyConstness!(shared inout const int, char) == inout const char));
static assert(is(CopyConstness!(const int, shared char) == shared const char));
static assert(is(CopyConstness!(const int, immutable char) == immutable char));
static assert(is(CopyConstness!(immutable int, const char) == immutable char));
}
/**
* Copies type qualifiers of $(D_PARAM From) to $(D_PARAM To).
*
* Type qualifiers copied are:
* $(UL
* $(LI const)
* $(LI immutable)
* $(LI inout)
* $(LI shared)
* )
* and combinations of these.
*
* Params:
* From = Source type.
* To = Target type.
*
* Returns: $(D_PARAM To) with the type qualifiers of $(D_PARAM From).
*
* See_Also: $(D_PSYMBOL CopyConstness).
*/
template CopyTypeQualifiers(From, To)
{
static if (is(From T == immutable T))
{
alias CopyTypeQualifiers = immutable To;
}
else static if (is(From T == const T))
{
alias CopyTypeQualifiers = const To;
}
else static if (is(From T == shared T))
{
alias CopyTypeQualifiers = shared To;
}
else static if (is(From T == shared const T))
{
alias CopyTypeQualifiers = shared const To;
}
else static if (is(From T == inout T))
{
alias CopyTypeQualifiers = inout To;
}
else static if (is(From T == shared inout T))
{
alias CopyTypeQualifiers = shared inout To;
}
else static if (is(From T == inout const T))
{
alias CopyTypeQualifiers = inout const To;
}
else static if (is(From T == shared inout const T))
{
alias CopyTypeQualifiers = shared inout const To;
}
else
{
alias CopyTypeQualifiers = To;
}
}
///
pure nothrow @safe @nogc unittest
{
static assert(is(CopyTypeQualifiers!(int, char) == char));
static assert(is(CopyTypeQualifiers!(const int, char) == const char));
static assert(is(CopyTypeQualifiers!(immutable int, char) == immutable char));
static assert(is(CopyTypeQualifiers!(inout int, char) == inout char));
static assert(is(CopyTypeQualifiers!(inout const int, char) == inout const char));
static assert(is(CopyTypeQualifiers!(shared int, char) == shared char));
static assert(is(CopyTypeQualifiers!(shared const int, char) == shared const char));
static assert(is(CopyTypeQualifiers!(shared inout int, char) == shared inout char));
static assert(is(CopyTypeQualifiers!(shared inout const int, char) == shared inout const char));
}
/**
* Evaluates to the unsigned counterpart of the integral type $(D_PARAM T) preserving all type qualifiers.
* If $(D_PARAM T) is already unsigned, $(D_INLINECODE Unsigned!T) aliases $(D_PARAM T).
*
* Params:
* T = A type.
*
* Returns: Unsigned counterpart of $(D_PARAM T).
*
* See_Also: $(D_PSYMBOL isSigned).
*/
template Unsigned(T)
if (isIntegral!T)
{
alias UnqualedType = Unqual!(OriginalType!T);
static if (is(UnqualedType == byte))
{
alias Unsigned = CopyTypeQualifiers!(T, ubyte);
}
else static if (is(UnqualedType == short))
{
alias Unsigned = CopyTypeQualifiers!(T, ushort);
}
else static if (is(UnqualedType == int))
{
alias Unsigned = CopyTypeQualifiers!(T, uint);
}
else static if (is(UnqualedType == long))
{
alias Unsigned = CopyTypeQualifiers!(T, ulong);
}
else
{
alias Unsigned = T;
}
}
///
pure nothrow @safe @nogc unittest
{
static assert(is(Unsigned!byte == ubyte));
static assert(is(Unsigned!short == ushort));
static assert(is(Unsigned!int == uint));
static assert(is(Unsigned!long == ulong));
static assert(is(Unsigned!(const byte) == const ubyte));
static assert(is(Unsigned!(shared byte) == shared ubyte));
static assert(is(Unsigned!(shared const byte) == shared const ubyte));
static assert(!is(Unsigned!float));
static assert(is(Unsigned!ubyte == ubyte));
}
/**
* Evaluates to the signed counterpart of the integral type $(D_PARAM T) preserving all type qualifiers.
* If $(D_PARAM T) is already signed, $(D_INLINECODE Signed!T) aliases $(D_PARAM T).
*
* Params:
* T = A type.
*
* Returns: Signed counterpart of $(D_PARAM T).
*
* See_Also: $(D_PSYMBOL isUnsigned).
*/
template Signed(T)
if (isIntegral!T)
{
alias UnqualedType = Unqual!(OriginalType!T);
static if (is(UnqualedType == ubyte))
{
alias Signed = CopyTypeQualifiers!(T, byte);
}
else static if (is(UnqualedType == ushort))
{
alias Signed = CopyTypeQualifiers!(T, short);
}
else static if (is(UnqualedType == uint))
{
alias Signed = CopyTypeQualifiers!(T, int);
}
else static if (is(UnqualedType == ulong))
{
alias Signed = CopyTypeQualifiers!(T, long);
}
else
{
alias Signed = T;
}
}
///
pure nothrow @safe @nogc unittest
{
static assert(is(Signed!ubyte == byte));
static assert(is(Signed!ushort == short));
static assert(is(Signed!uint == int));
static assert(is(Signed!ulong == long));
static assert(is(Signed!(const ubyte) == const byte));
static assert(is(Signed!(shared ubyte) == shared byte));
static assert(is(Signed!(shared const ubyte) == shared const byte));
static assert(!is(Signed!float));
static assert(is(Signed!byte == byte));
}
/**
* Retrieves the target type `U` of a pointer `U*`.
*
* Params:
* T = Pointer type.
*
* Returns: Pointer target type.
*/
template PointerTarget(T)
if (isPointer!T)
{
static if (is(T U : U*))
{
alias PointerTarget = U;
}
}
///
pure nothrow @safe @nogc unittest
{
static assert(is(PointerTarget!(bool*) == bool));
static assert(is(PointerTarget!(const bool*) == const bool));
static assert(is(PointerTarget!(const shared bool*) == const shared bool));
static assert(!is(PointerTarget!bool));
}