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0 pointsnessus4213y ago0 comments

> This is true, but likewise, its not safe to parameterize functionality by passing callbacks unless you know what the function you are passing the callback to expects of callback functions

Of course; this goes without saying. But when programming in an OO style, programmers often override methods thinking that they are only changing the behavior of that one method, when in fact they could be inadvertently changing the behavior of other methods in the class.

When passing in functions as arguments, on the other hand, this makes it much more explicit what is supported and what isn't.

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dragonwriter13y ago· 2 in thread

> Of course; this goes without saying. But when programming in an OO style, programmers often override methods thinking that they are only changing the behavior of that one method

This is not a problem with using classes or overriding methods, its a problem either with either failure to document behavior on the part of the library author or failure to read documentatio on the part of the library consumer.

Neither of those is any less a danger in the case here the design of the library involves parameterizing functionality by passing functions around as parameters.

nessus42OP13y ago

> This is not a problem with using classes or overriding methods, its a problem either with either failure to document behavior on the part of the library author or failure to read documentation on the part of the library consumer.

Missing or poor documentation is a sad reality of programming in the real world. And is the normal state when working on a active project with other developers. This would be mitigated if programmers were very careful about declaring methods to be final if it's not perfectly safe to override them, but most are not that careful, or even fully aware of the issues. And in many programming languages there is no way to declare a method to be final.

> Neither of those is any less a danger in the case here the design of the library involves parameterizing functionality by passing functions around as parameters.

When programming in a functional style, functionality that is not intended to be modified by the client will not provide a parameter for doing so, so this significant source of confusion is eliminated.

dragonwriter13y ago

> This would be mitigated if programmers were very careful about declaring methods to be final if it's not perfectly safe to override them

Its always perfectly safe to override a method if you maintain its required features. Its rarely, if ever, perfectly safe to do so if you don't. The issue is correctly documenting the required features.

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