Logo

Programming-Idioms

  • Python
  • Rust
  • Pascal
  • Lisp

Idiom #123 Assert condition

Verify that predicate isConsistent returns true, otherwise report assertion violation.
Explain if the assertion is executed even in production environment or not.

(assert (isConsistent))

Assertion is always executed.
assert isConsistent

raises AssertionError Exception.

Running Python with option -O or with PYTHONOPTIMZE
environment variable suppresses all asserts.
assert!(is_consistent);
{$ASSERTIONS ON}
Assert(isConsistent,'isConsistent assertion failed.');

Assert() will raise an EAssertionFailed exception if the condition is False.

If you leave out the {$ASSERTIONS ON} (e.g. in production code), the Assert() statement will not be compiled into the program.
#include <assert.h>
assert(isConsistent());

If NDEBUG is defined, the assert macro becomes void. Therefore, such expressions must not have side effects.
New implementation...
< > ⌨
programming-idioms.org 
(assert (isConsistent))
assert isConsistent
assert!(is_consistent);
{$ASSERTIONS ON}
Assert(isConsistent,'isConsistent assertion failed.');
assert(isConsistent());
(assert (isConsistent))
(assert (true? (isConsistent)))
assert(isConsistent());
var result = isConsistent();
Trace.Assert(result);
var result = isConsistent();
Debug.Assert(result);
assert(isConsistent);
assert(isConsistent);
if (.not. isconsistent) stop "Inconsistent state"
if !isConsistent() {
	panic("State consistency violated")
}
assert isConsistent()
let x' = assert isConsistent x
console.assert(_isConsistent);

assert isConsistent() : "State consistency violated";
assert(isConsistent() , "Assertion violation") 
assert(_isConsistent);
assert { is_consistent };
raise unless isConsistent