On 26/11/2020 08:43, Chris Angelico wrote:
On Thu, Nov 26, 2020 at 6:19 AM dn via Python-list
<python-list@python.org> wrote:
I've got a program which accepts an optional env variable listing a single
or multiple directory for the app to use. I've done a bit of a search and
see both a comma and semicolon being used/suggested as a path separator.
Any consensus on which is better?
...
The one thing I really would *not* recommend is a DWIM arrangement of
having it guess at which delimiter to use. :)
Interesting description. Historically I've always quoted "Postel's Law":
...
In psychology the jargon is "satisficing" - being happy with whichever
works when we try it: Why look [for a label]? I'll just push the door
away from me - and if that doesn't work, then I'll pull on the handle
(but if it's locked, my frustration will result in words being said...)
How quickly does something 'easy' move from 'who cares' to 'almost anger'?
So, if some users are likely to assume commas, but others [semi-]colons,
perhaps the best service is to enable either/both! (hint: str.translate() )
That's absolutely fine IF and ONLY IF you can guarantee that all those
forms of punctuation cannot occur within the elements. I do this kind
of thing all the time when it's unambiguous; for instance, a multiline
input saying "enter Twitch channel names" takes the user input and
splits it on comma, semicolon, newline, or space, and then trims
individual entries with "http%*[s]://twitch.tv/%s%*[?/]" to get to
just the channel name. That works really well, because there's no way
that a channel name can contain that sort of punctuation.
That's the dichotomy: as soon as we aim for 'flexibility', we risk
ambiguity.
Sometimes it might be better to go with the Zen of Python: "There should
be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch."*
Sadly, whilst we coders can reasonably be encouraged "In the face of
ambiguity, refuse the temptation to guess.", it will never appear in
(many) user's manifestos - possibly an 'age' thing, more likely a "don't
think" thing...
* I'm amused (not offended) by this casual racism, but wonder how it
continues to be allowed given the Python Foundation's diversity principles.
That said, Python/PSL enables differences between OpSys to be
'abstracted away', eg using / or \ as separator in a file/dir's path.
Where applicable, use!
It's completely NOT okay if you're working with something that might
contain anything - especially if your users aren't thinking about the
different separators. You might get away with using a comma to
Well, as debated earlier, Steve Krug suggests that users
aren't/shouldn't be thinking. So, fallacies abound!
separate names of people, happily working with lists like "Fred,
Barney, Wilma" and "Elsa, Anna, Kristoff, Sven" and "Steve, Steven,
Stephen, Stefan, Stephanie", but then along comes "Charles, Prince of
Wales" and suddenly your system breaks. But far worse than simply
using commas as separators is magically deciding to do so on the basis
of what someone's given you to parse. If someone tries to use "Fred;
Barney; Wilma" and "Elsa; Anna; Kristoff; Sven" and it works fine,
then they might expect that it'd be safe to list the British royal
family with semicolons between their names - but your code suddenly
decides to use commas, and now everything's broken.
Hey, they're the Australian Royal Family too, aren't they?
(cue Republicanism sentiment)
How often does Prince Charles (the rest is "title" not name, BTW - thus
"Charles Windsor" or even "Charles Wales") visit your web site/use your
app?
Wouldn't you expect to cater less to princes and more to frogs?
The worst part of a DWIM system is that it's hard - often impossible -
to correct its errors. You end up fighting with it to interpret your
input correctly. With a simpler system, it might be bizarre and arcane
(seriously, look at bash's argument splitting and interpolation
rules!), but at least you don't have to fight it, and what works with
one set of data will definitely work with another.
Yes, the issue lies with, and starts with, the combination. Referencing
@Eryk's post, even users with knowledge of their OpSys will come to the
problem with a different set of assumptions (hopes, fears, ...)
Accordingly, it may be appropriate to eschew free-form lists entirely. Thus:
MYPATH=Z:\Spam
MYPATH=foo
MYPATH=bar
... but then sit-back and wait for the first help-call from a user
worrying that the first/last is the only specification that will be applied.
Are we likely to 'win' any-time soon?
Clearly, what might be appropriate or usable in one 'solution', should
be out-right rejected in another situation.
Conversely, consider the level of frustration faced by a user who
expects one thing but is *restricted* to something else, eg sites which
ask one to register a password, but don't advise up-front that they
require some arcane combination/mix of characters - until after you've
entered your [ignorant] choice - twice. Grrr!
Ohh I hear you on that. Especially when they think they need more
security than everyone else, so they say "have to have two uppercase,
two lowercase, one digit, and two symbols". And then they reject
password after password because, apparently, "!" isn't one of their
list of symbols. Or something. And of course, they never permit long
passwords. Oh no, that would be way too helpful, not to mention that
it'd actually be more secure. Sigh.
Or... how about the form requesting an email address, which is rejected
- presumably because the RegEx/library-routine has restrictions which
don't include certain 'new' TLDs?
Well excuse me, but if I am responding to *your* email-message, which
*you* sent to my email-address, surely the address has been proven and
MUST be 'legal'!?
(and why am I entering it manually, when the email-message's link could
have included same?)
Welcome to the wonderful world of UX!
We (computer people) have long been encouraged to 'make things
idiot-proof'. The trouble with this injunction, is that the harder we
try to achieve such, the faster 'the world' comes up with a better class
of idiot!
By which I don't mean to imply that it is not worth trying. I spend
quite a bit of time and effort 'in UX' - simply because there is often
no-one else doing it (proper Agile teams aside).
Why? There's plenty of 'hard' and anecdotal research which confirms that
if users find a tool 'difficult', 'awkward', or even 'different' (from
what they expect), then it will be dropped!
--
Regards =dn
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