Anonymous user
Assertions: Difference between revisions
added Nemerle
(D entry rewritten and completed) |
(added Nemerle) |
||
Line 550:
Assertions can be ignored in the compiler by using the <code>-a</code> switch.
=={{header|Nemerle}}==
A basic assertion uses the <tt>assert</tt> keyword:
<lang Nemerle>assert (foo == 42, $"foo == $foo, not 42.")</lang>
Assertion violations throw an <tt>AssertionException</tt> with the line number where the assertion failed and the message provided as the second parameter to assert.
Nemerle also provides macros in the <tt>Nemerle.Assertions</tt> namespace to support preconditions, postconditions and class invariants:
<lang Nemerle>using Nemerle.Assertions;
class SampleClass
{
public SomeMethod (input : list[int]) : int
requires input.Length > 0 // requires keyword indicates precondition,
// there can be more than one condition per method
{ ... }
public AnotherMethod (input : string) : list[char]
ensures value.Length > 0 // ensures keyword indicates postcondition
{ ... } // value is a special symbol that indicates the method's return value
}</lang>
The design by contract macros throw <tt>Nemerle.AssertionException</tt>'s unless another Exception is specified using the <tt>otherwise</tt> keyword after the <tt>requires/ensures</tt> statement.
For further details on design by contract macros, see [http://nemerle.org/wiki/index.php?title=Design_by_contract_macros here].
=={{header|Nimrod}}==
| |||