And returns a function that returns true when all provided functions return true.

Contains returns a function that returns true when the provided string or byte slice is found within another string or byte slice.

GreaterThan returns a function that returns true when the provided value is greater than a threshold.

IsEqual returns a function that returns true when the provided value is equal to some value.

IsEven returns true when the provided integer is even.

IsOdd returns true when the provided integer is odd.

IsZero returns true when the provided value is the zero value for its type.

LessThan returns a function that returns true when the provided value is less than a threshold.

Match returns a function that returns true when the provided string or byte slice matches a pattern.

Not returns a function that inverts the result of the provided function.

NotEqual returns a function that returns true when the provided value is not equal to some value.

Or returns a function that returns true when any of the provided functions return true.

Passthrough returns a function that returns true for any value.

Passthrough2 returns a function that returns true for any pair of values.