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Module std.meta
Templates to manipulate template argument lists (also known as type lists).
Some operations on alias sequences are built in to the language, such as TL[n] which gets the nth type from the alias sequence. TL[lwr .. upr] returns a new type list that is a slice of the old one.
Several templates in this module use or operate on eponymous templates that take a single argument and evaluate to a boolean constant. Such templates are referred to as template predicates.
References
Based on ideas in Table 3.1 from Modern C++ Design, Andrei Alexandrescu (Addison-Wesley Professional, 2001)
Templates
| Name | Description |
|---|---|
allSatisfy
|
Tests whether all given items satisfy a template predicate, i.e. evaluates to
F!(T[0]) && F!(T[1]) && ... && F!(T[$ - 1]).
|
anySatisfy
|
Tests whether any given items satisfy a template predicate, i.e. evaluates to
F!(T[0]) || F!(T[1]) || ... || F!(T[$ - 1]).
|
DerivedToFront
|
Returns the typetuple TList with the types sorted so that the most derived types come first. |
Filter
|
Filters an |
MostDerived
|
Returns the type from TList that is the most derived from type T. If none are found, T is returned. |
NoDuplicates
|
Returns a typetuple created from TList with the all duplicate types removed. |
Reverse
|
Returns a typetuple created from TList with the order reversed. |
staticMap
|
Evaluates to |
templateAnd
|
Combines several template predicates using logical AND, i.e. constructs a new predicate which evaluates to true for a given input T if and only if all of the passed predicates are true for T. |
templateNot
|
Negates the passed template predicate. |
templateOr
|
Combines several template predicates using logical OR, i.e. constructs a new predicate which evaluates to true for a given input T if and only at least one of the passed predicates is true for T. |
Enum values
| Name | Type | Description |
|---|---|---|
staticIndexOf
|
Returns the index of the first occurrence of type T in the sequence of zero or more types TList. If not found, -1 is returned. |
Aliases
| Name | Type | Description |
|---|---|---|
AliasSeq
|
TList
|
Creates a sequence of zero or more aliases. This is most commonly used as template parameters or arguments. |
Erase
|
GenericErase!(T,TList)
|
Returns a typetuple created from TList with the first occurrence, if any, of T removed. |
EraseAll
|
GenericEraseAll!(T,TList)
|
Returns a typetuple created from TList with the all occurrences, if any, of T removed. |
IndexOf
|
Kept for backwards compatibility | |
Replace
|
GenericReplace!(T,U,TList)
|
Returns a typetuple created from TList with the first occurrence of type T, if found, replaced with type U. |
ReplaceAll
|
GenericReplaceAll!(T,U,TList)
|
Returns a typetuple created from TList with all occurrences of type T, if found, replaced with type U. |