Singleton types
Laatst bijgewerkt:
Singleton types
Singleton types are those which allow only one value.
PHP has support for two singleton types:
as of PHP 8.0.0 and
as of PHP 8.2.0.
false``true
Waarschuwing: > Prior to PHP 8.2.0 the type could only be used as part of a .
falseunion type
Opmerking: > It is not possible to define custom singleton types. Consider using an instead. enumerations