I'm currently reading the book "Code Complete" (I don't know the author name), which gives a lot of useful best practices. It's not specifically about one programming language. The author stresses that the majority of those practices are a matter of consensus/consistency and not a matter of religion. There is no one best way to do it. Re: functions, the author recommends that they have one purpose and one purpose only, and that a function returns only one result.
Cheers!! Albert-Jan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In the face of ambiguity, refuse the temptation to guess. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ --- On Mon, 11/30/09, Alan Gauld <alan.ga...@btinternet.com> wrote: From: Alan Gauld <alan.ga...@btinternet.com> Subject: Re: [Tutor] Python best practices To: tutor@python.org Date: Monday, November 30, 2009, 1:57 AM "spir" <denis.s...@free.fr> wrote >> > - functions should return one value (im not 100% of this one) >> >> I 100% disagree or with this one. > > Could you explain this bit, Lie? I'm very interested. > I use multiple-value result myself, for it's so practicle in given cases. My take on this is that in Python its OK to return multiple values if it is as a tuple - because a tuple is really a single value. Its like returning a record in Pascal or a struct in C or a List in Lisp... > But it makes me uneasy; also have the impression (why?) it > reveals wrong design. Its better than.... > a function both to have an effect (eg assignment outside the func scope) and > return a value. Side effects in functions are nearly always bad news and are always avoidable if you can return multiple values (or pass arguments by reference). > "Command-Query Separation Principle" (Eiffel) & Pascal "procedure vs > function". You can have Command/Query separation without having side-effects. A Query is a procedure or function that doesn't change anything but just returns a result. A Command changes something, but it can be the thing passed to it - or if a method of a class the internal data of the class. Again a command can be a function or a procedure. Those are separate concepts. (I very rarely write procedures in real programs - there is nearly always something useful you can return - and in an object that's usually a minimum of self! (Returning self is the default idiom in Smalltalk - it allows chaining of methods) HTH, Alan G. _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
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