mirrors/phobos
1
0
Fork 0
mirror of https://github.com/dlang/phobos.git synced 2025-05-12 15:17:12 +03:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Document that types larger than maxSize will be automatically boxed

Browse source
This commit is contained in:
MetaLang 2015-04-12 02:19:17 -03:00
parent cdd73be74c
commit f97aa28724
1 changed files with 11 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

21
std/variant.d
View file

@ -138,10 +138,12 @@ template This2Variant(V, T...)
* limited type universe (e.g., $(D_PARAM Algebraic!(int, double, * limited type universe (e.g., $(D_PARAM Algebraic!(int, double,
* string)) only accepts these three types and rejects anything * string)) only accepts these three types and rejects anything
* else).) $(LI $(B Variant): An open discriminated union allowing an * else).) $(LI $(B Variant): An open discriminated union allowing an
* unbounded set of types. The restriction is that the size of the * unbounded set of types. If any of the types in the $(D_PARAM Variant)
* stored type cannot be larger than the largest built-in type. This * are larger than the largest built-in type, they will automatically
* means that $(D_PARAM Variant) can accommodate all primitive types * be boxed. This means that even large types will only be the size
* and all user-defined types except for large $(D_PARAM struct)s.) ) * of a pointer within the $(D_PARAM Variant), but this also implies some
* overhead. $(D_PARAM Variant) can accommodate all primitive types and
* all user-defined types.))
* *
* Both $(D_PARAM Algebraic) and $(D_PARAM Variant) share $(D_PARAM * Both $(D_PARAM Algebraic) and $(D_PARAM Variant) share $(D_PARAM
* VariantN)'s interface. (See their respective documentations below.) * VariantN)'s interface. (See their respective documentations below.)
@ -151,7 +153,8 @@ template This2Variant(V, T...)
* and with the list of allowed types ($(D_PARAM AllowedTypes)). If * and with the list of allowed types ($(D_PARAM AllowedTypes)). If
* the list is empty, then any type up of size up to $(D_PARAM * the list is empty, then any type up of size up to $(D_PARAM
* maxDataSize) (rounded up for alignment) can be stored in a * maxDataSize) (rounded up for alignment) can be stored in a
* $(D_PARAM VariantN) object. * $(D_PARAM VariantN) object without being boxed (types larger
* than this will be boxed).
* *
*/ */
@ -170,9 +173,7 @@ private:
/** Tells whether a type $(D_PARAM T) is statically allowed for /** Tells whether a type $(D_PARAM T) is statically allowed for
* storage inside a $(D_PARAM VariantN) object by looking * storage inside a $(D_PARAM VariantN) object by looking
* $(D_PARAM T) up in $(D_PARAM AllowedTypes). If $(D_PARAM * $(D_PARAM T) up in $(D_PARAM AllowedTypes).
* AllowedTypes) is empty, all types of size up to $(D_PARAM
* maxSize) are allowed.
*/ */
public template allowed(T) public template allowed(T)
{ {
@ -1362,10 +1363,10 @@ unittest
$(D_PARAM Variant) is an alias for $(D_PARAM VariantN) instantiated $(D_PARAM Variant) is an alias for $(D_PARAM VariantN) instantiated
with the largest of $(D_PARAM creal), $(D_PARAM char[]), and $(D_PARAM with the largest of $(D_PARAM creal), $(D_PARAM char[]), and $(D_PARAM
void delegate()). This ensures that $(D_PARAM Variant) is large enough void delegate()). This ensures that $(D_PARAM Variant) is large enough
to hold all of D's predefined types, including all numeric types, to hold all of D's predefined types unboxed, including all numeric types,
pointers, delegates, and class references. You may want to use pointers, delegates, and class references. You may want to use
$(D_PARAM VariantN) directly with a different maximum size either for $(D_PARAM VariantN) directly with a different maximum size either for
storing larger types, or for saving memory. storing larger types unboxed, or for saving memory.
*/ */
alias Variant = VariantN!(maxSize!(creal, char[], void delegate())); alias Variant = VariantN!(maxSize!(creal, char[], void delegate()));