Designing Good Interfaces

Post by tommyage » Thu, Mar 16, 2023, 9:11 PM UTC

Jtsummers wrote: post #28

tommyage wrote: post #21

Earlier quoted context omitted.

> Is this what we refer to as design by contract? No. One need a specification of the intended behaviour. Behind this specification lays the interface (data type, here a Object-class). This data type on the other hand can have different representations. Design by contract is a term i didn't read as an agreed scientific term. It is used in OO-languages for some pattern, where you "generate" (read imply) a specificatio…

Invariants are not a synonym for mixins, I'm not even sure where that idea might have come from. Invariants are assertions that are true throughout a program or subset of a program (like loop invariants). Where did you get this notion they were synonyms for mixins and what would that even mean?

> Invariants are not a synonym for mixins, I'm not even sure where that idea might have come from. Invariants are assertions that are true throughout a program or subset of a program (like loop invariants). Where did you get this notion they were synonyms for mixins and what would that even mean?

It was my own understanding; Thanks for suggesting clarification. I falsely associated such mixins with encapsulated behaviour. It was my take on mixins and may have translated the term invariant wrong. Appreciated.

Post by tommyage » Thu, Mar 16, 2023, 9:24 PM UTC

sterasody wrote: post #25

tommyage wrote: post #21

Earlier quoted context omitted.

> Is this what we refer to as design by contract? No. One need a specification of the intended behaviour. Behind this specification lays the interface (data type, here a Object-class). This data type on the other hand can have different representations. Design by contract is a term i didn't read as an agreed scientific term. It is used in OO-languages for some pattern, where you "generate" (read imply) a specificatio…

Thanks for your reply! I will need more research to reflect on the examples you give. I discovered the concept from books and documentations, for example: - https://learn.adacore.com/courses/intro-to-ada/chapters/cont... - https://www.eiffel.org/doc/solutions/Design_by_Contract_and_... and it seemed to me the main concern was program correctness/consistency. Maybe I mix up different concerns and good interface design…

> Thanks for your reply! I will need more research to reflect on the examples you give.

Please note my sibling answer which shows I am opinionated. I have memorized my own takes from such terms so researching about my answer may be time not used well. Sorry.

> - https://www.eiffel.org/doc/solutions/Design_by_Contract_and_...

Does indeed overlap. I only read about contract-based programming; contract by design via API documentation in a java environment.

> and it seemed to me the main concern was program correctness/consistency

It is. There are multiple factors to deploying correct software though.

> Maybe I mix up different concerns and good interface design is more about satisfying use case?

Apparently your are on the right track. But I would strongly agree on the latter. Such formal correctness proves didn't cross my career yet. But I am assuming safety-critical systems or systems haed to update may benefit here the most. Which would explain my lack of certainty.

Keep it up; Sorry.

Re: Designing Good Interfaces

Re: Designing Good Interfaces