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How so? The major design by contract language I know of is D, and its contracts are essentially asserts that are either placed at the beginning of the body or p
by beatgammit 8y ago
How so? The major design by contract language I know of is D, and its contracts are essentially asserts that are either placed at the beginning of the body or prior to all returns.
You can certainly get substantially similar behavior just using asserts at the beginning of the function body and ensuring asserts at the end before a return are hit by all code paths (e.g. make an anonymous function that contains the body, then call it wrapped in a try/catch and assert on the return value.
Unless I'm missing something about design by contract, it's essentially just asserts at the beginning and end of a function.
- zamalek 8y agoPrecondition (called invariant here): a set of conditions that must be met in order to call a method. Another name for argument validation, but it can be other things (e.g. connected must be true before calling methods on a connection). Postcondition: guarantees that a method makes. For instance, it won't return null. Invariants (incorrectly used): conditions that always hold true on a type, e.g. the starting index on a slice must always be greater or equal to zero. https://en.m.wikipedia.org/wiki/Design_by_contract https://en.m.wikipedia.org/wiki/Design_by_contract I guess D is guessing via implications, but from what you've said it can't support invariants, meaning it doesn't strictly qualify as DbC.