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Template `std.meta.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.


						
				template templateOr(Preds...)
				;

The predicates are evaluated from left to right, aborting evaluation in a short-cut manner if a true result is encountered, in which case the latter instantiations do not need to compile.

Example

import std.traits : isPointer, isUnsigned;

alias isPtrOrUnsigned = templateOr!(isPointer, isUnsigned);
static assert( isPtrOrUnsigned!uint &&  isPtrOrUnsigned!(short*));
static assert(!isPtrOrUnsigned!int  && !isPtrOrUnsigned!(string));

// An empty sequence of predicates never yields true.
alias alwaysFalse = templateOr!();
static assert(!alwaysFalse!int);

Authors

Walter Bright, David Nadlinger

License

Boost License 1.0.