On Monday, August 11, 2014 3:31:08 AM UTC+5:30, Roy Smith wrote: > Mark Lawrence wrote:
> > On 10/08/2014 19:26, Rustom Mody wrote: > > > Its when we have variables that are assigned in multiple places that > > > we start seeing mathematical abominations like > > > x = x+1 > > I'm not bothered about it being a mathematical or any other type of > > abomination. It works, practically beats purity, so if it ain't broke, > > please don't fix it, for some definition of fix. > I'm with Mark. This isn't math, it's programming. Sure, the > intersection of the two is non-null, but they are different things. > I'll often do things like: > for line in input: > line = line.strip() > # do more stuff So would I > Sure, I could invent some other variable name to avoid re-using the same > name, but does: > for line in input: > stripped_line = line.strip() > # do more stuff > really make this any easier to read or understand? I think not. You are switching between software-engineer and teacher hat. As a software engineer you (and I and possibly most reasonable people) would do things like that. As a teacher when you introduce problematic concepts you have to answer questions -- possibly embarrassing -- about them. Just as parents need to talk of 'birds-and-bees' to their children sometime but also need good sense and judgement as to when, likewise teachers should deliver maturity-building easier stuff before maturity-needing harder ideas. Assignment is definitely in the latter category because we have to talk of time, environments and so on. When one explicates (and not handwaves) these pre-requisites -- as happens in denotational semantics or in any language implementation -- then assignment is seen to be as higher-order a concept as any other 2 level lambda expression. -- https://mail.python.org/mailman/listinfo/python-list
