Finds whether the given variable is a scalar.
Scalar variables are those containing an int, float, string or bool. Types array, object, resource and null are not scalar.
is_scalar does not consider resource type values to be scalar as resources are abstract datatypes which are currently based on integers. This implementation detail should not be relied upon, as it may change.
is_scalar does not consider NULL to be scalar.
The variable being evaluated.
Returns true if value is a scalar, false otherwise.