12.2.4 Checking conditions: assert
The assert command breaks out of a function with an error.
-
assert takes one argument:
bool, a boolean.
- assert(bool) does nothing if
bool is true, it returns from the function with an error if
bool is false.
Example.
Define the function:
Input:
sqofpos(x):= {assert(x > 0); return x^2;}
then:
sqofpos(4)
Output:
Input:
sqofpos(-4)
Output:
assert failure: x>0 Error: Bad Argument Value
since -4 > 0 is false.