Clever vs. Readable

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Re: Clever vs. Readable by BrowserUk (Patriarch) on Aug 09, 2008 at 17:36 UTC
I've always preferred `my $result = $a < $b ? $a : $b;`. Simple, clear and hands down fastest. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l]
Re^2: Clever vs. Readable by GrandFather (Saint) on Aug 09, 2008 at 21:09 UTC
"hands down fastest" certainly. Fairly simple and reasonably clear I'd agree. As simple, clear and reliable to code as min? Not a chance. For trivial variables the ternary operator is ok. But, as soon as any indirection or any other complication in obtaining the values is required the ternary solution becomes unclear and starts to lose its speed advantage. If calculating the values has side effects the ternary version simply isn't tenable. Perl reduces RSI - it saves typing	[reply]
Re^3: Clever vs. Readable by BrowserUk (Patriarch) on Aug 09, 2008 at 23:47 UTC
I said "I prefer". You are of course free to code as you choose, but don't invoke the justifiction of reliability. The day I cannot correctly code `my $min = $a < $b ? $a : $b;` is the day I'll go looking for a CPAN module to do it. At the same time I'll go looking for something to help me with: `if( $a < $b ) { ## Do what is required when $a is the lessor } else { ## Do what is required when $b is the lessor }` [download] Any thoughts? Maybe you'd code that as `if( min( $a, $b ) == $a ) ...`? If I've to demolish a wall, or drive a nail, I'll reach for a hammer. But when I've a nut to crack, it stays in the toolkit. And if you want to play what-if games. What if `$a` and `$b` are overloaded objects? `#! perl -slw use strict; use X; use List::Util qw[ min ]; my $a = X->new( .5, .5, .5, 1 ); my $b = X->new( .7, .9, .4, 1 ); print $a < $b ? 'a is the lessor' : 'b is the lessor'; print "\n-------\n"; print min( $b, $a ); __END__ [ 0:38:13.97] c:\test>junk3 a is the lessor ------- Argument "X=ARRAY(0x1824550)" isn't numeric in subroutine entry at c:\ +test\junk3.pl line 10. Argument "X=ARRAY(0x2251a4)" isn't numeric in subroutine entry at c:\t +est\junk3.pl line 10. X=ARRAY(0x1824550)` [download] Even ignoring the warnings, did `min()` get the answer right? And if it did, was it for the right reasons or just some fortuitous accident that'll come back and bite once it goes into production? Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]
Re^3: Clever vs. Readable by JavaFan (Canon) on Aug 09, 2008 at 21:18 UTC
I find `$a < $b ? $a : $b` clearer than `min ($a, $b)`. The former in unambiguous, the latter uses an ambiguous abbreviation. It's likely to return the minimum of both values, but perhaps it returns `$a - $b`, or `(-$a, -$b)`. There's no doubt in `$a < $b ? $a : $b`, but there's some doubt in `min ($a, $b)`.	[reply] [d/l] [select]
Re^4: Clever vs. Readable by GrandFather (Saint) on Aug 09, 2008 at 22:36 UTC
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Re: Clever vs. Readable by FunkyMonk (Chancellor) on Aug 09, 2008 at 17:15 UTC
There's an awful lot of TheDamian's opinion in PBP that I disagree with, but in this case he's absolutely spot on. Clarification: What I meant by the above was that readable beats clever every time. I didn't mean to suggest that min() should be used to find the minimum of two values. I'd use the ternary operator just as BrowserUK suggested.	[reply]
Re^2: Clever vs. Readable by shmem (Chancellor) on Aug 09, 2008 at 23:14 UTC
but in this case he's absolutely spot on. spot on? nightmare? so what does he say about the Schwartzian transform? hell of a nightmare, I guess. He's not spot on choosing a too simple construct to make an argument of readability vs. maintainability. A perl code maintainer needs a training in TIMTOWTDI, and this one is a good piece of code for that.	[reply]
Re^3: Clever vs. Readable by Porculus (Hermit) on Aug 10, 2008 at 11:30 UTC
The Schwarzian transform is a standard and widely used Perl idiom. This "min" example is neither of those things. You can't really compare them. While Perl programmers do need to understand TIMTOWTDI, they also need to understand that some of those ways are rarely appropriate. This is indeed a great example to teach them that with -- precisely because it's so unreadable. It's a great example of OWTDI that IMO few experienced programmers would seriously consider for use in production code. (FWIW, IIRC PBP has nothing against the ST but recommends that it be preceded by a comment identifying the construct.)	[reply]
Re: Clever vs. Readable by swampyankee (Parson) on Aug 09, 2008 at 17:23 UTC
I'm voting for readability, in agreement with Dr Conway. Frequently, code maintenance is assigned to the programmers with the least experience in a language, so terseness is not clever. I've been handed code to maintain in COBOL and PL/1, never having worked in either, and I had never even read a book about COBOL before. Information about American English usage here and here. Floating point issues? Please read this before posting. — emc	[reply]
Re^2: Clever vs. Readable by BrowserUk (Patriarch) on Aug 26, 2008 at 23:38 UTC
Frequently, code maintenance is assigned to the programmers with the least experience in a language, And until that dumbest of dumb inequities is addressed, software development will have as much in common with 'the professions' as fly-by-night roofers and itinerant driveway layers. I started into a long and vociforous rant when it dawned on me that I was repeating myself, albeit in a slightly different context: Code maintenance is often seen as a secondary activity, somehow lesser than 'greenfield' coding. It is not! Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply]
Re: Clever vs. Readable by TGI (Parson) on Aug 09, 2008 at 17:46 UTC
Readable is best. The `min` example is best if you might need to add extra elements to the list. Otherwise, BrowserUK has the right answer. TGI says moo	[reply]
Re: Clever vs. Readable by zentara (Archbishop) on Aug 09, 2008 at 18:14 UTC
Don't forget the ultimate in readability, clunkiness, and lack of cleverness: (for new programmers) `my $min; if( $a <= $b){ $min = $a}else{ $min = $b }` [download] I'm not really a human, but I play one on earth Remember How Lucky You Are	[reply] [d/l]
Re^2: Clever vs. Readable by Your Mother (Archbishop) on Aug 09, 2008 at 20:53 UTC
Yeah, but what happens when this simplistic (not simple) approach is taken in the wild is that the `if/else` grows into a 300 line `if/elsif` and the `else` to catch fail cases never seems to be there. I'm going through this again at work because a very experienced and generally intelligent manager there would rather do an open-ended if/elsif tree than a hash lookup, "Because it's easier to read."	[reply] [d/l] [select]
Re^2: Clever vs. Readable by JavaFan (Canon) on Aug 09, 2008 at 20:55 UTC
In that case, I'd prefer ALGOL: `min := IF a < b THEN a ELSE b FI;` [download] (It's a long time since I last coded in ALGOL, so I might have details of the syntax not correct).	[reply] [d/l]
Re: Clever vs. Readable by EvanK (Chaplain) on Aug 09, 2008 at 19:05 UTC
Using the "Obfuscation" section of PM as an example, there are many of us that consider it an art as well as a craft. As such, they both have their place. Perl as an art Anything can be an art if you're good enough at it, and coding is no exception. This is more coding for coding's sake, or to keep one's skills honed during downtime, that allows us to create (and appreciate) truly clever obfuscated code. It's not meant for fully functional projects or production environments. Perl as a craft In this case, readability is key. With anything useful you build, it is very likely that, at some point, someone other than you will be maintaining it. In these cases (most of the time), you want to use an extra several lines of code to clearly illustrate what you're doing and how.	[reply]
Re: Clever vs. Readable by Perlbotics (Archbishop) on Aug 09, 2008 at 22:40 UTC
Considering the poor maintainer (probably oneself), I would vote for readability most of the time. However, shorter code sometimes executes faster (the OPs example probably not). E.g., I think of something with implicit loops like `map{...}` which gave me some problems decoding when I was a Perl beginner. If terse code is a must, proper commenting is 'more' mandatory. Consider this: `$result = ($a, $b)[$b <= $a]; # minimum ($a, $b)` Less than 20 additional characters read in a fraction of a second helps to save some dozens seconds decoding and the uncomfortable feeling to have something missed. From my point of view, clever is okay when there is a gain, be it speed of execution or degree of obfuscation.	[reply] [d/l] [select]
Re: Clever vs. Readable by JavaFan (Canon) on Aug 09, 2008 at 20:57 UTC
I'd write either: `$min = $a < $b ? $a : $b;` [download] or `$min = $a; $min = $b if $b < $a;` [download]	[reply] [d/l] [select]
Re^2: Clever vs. Readable by JadeNB (Chaplain) on Aug 26, 2008 at 23:06 UTC
`$min = $a; $min = $b if $b < $a;` [download] Not only that—if you change `$b < $a` to `$b < $min` in the second line, then you're most of the way to addressing the problem with (I think) all the other non-`min` solutions so far, namely, that they don't handle more than two elements! (I sure do love that `[ $a => $b ]->[ $b <= $a ]` one, though—so much so that, when I heard about it here, I ran out and got Effective Perl just to see if it had more like that. Since the rest of the advice was good, rather than pain-on-the-maintenance-programmer-inflicting, I guess that I have to stick with the obfuscated Perl section here.)	[reply] [d/l] [select]
Re: Clever vs. Readable by jdrago_999 (Hermit) on Aug 10, 2008 at 16:21 UTC
What about: `my ($min) = sort( $a, $b );`	[reply] [d/l]
Re^2: Clever vs. Readable by betterworld (Curate) on Aug 10, 2008 at 16:34 UTC
Only this sorts alphabetically. And it's complicated to change the sort type because `$a` and `$b` are lexical variables here. Apart from that, it looks rather clever, too.	[reply] [d/l] [select]
Re^3: Clever vs. Readable by jdrago_999 (Hermit) on Aug 10, 2008 at 17:25 UTC
You are absolutely correct. My bad :)	[reply]
Re: Clever vs. Readable by shmem (Chancellor) on Aug 09, 2008 at 23:00 UTC
So whose side are you on? On either side. Readability wins Ok, but this piece of code is not too complex, and it provides a good training to anybody who doesn't get at a glance what is meant. A benefit to any maintainer.	[reply]
Re: Clever vs. Readable by dokkeldepper (Friar) on Aug 11, 2008 at 05:29 UTC
As for me, the point in this is not so much the "cleverness". It is merely that the example from EP gives one another perspective to a trivial problem, that may be useful in other places. Both approaches have their merit, however their context is totally different. PBP gives advice how to write maintainable progams, EP teaches idioms and ideas on perl.(I own both books, btw)	[reply]
Re: Clever vs. Readable by ikegami (Patriarch) on Aug 09, 2008 at 17:28 UTC
Since only one of the three is actually correct, I'll pick that one. Trying to be clever doesn't help.	[reply]
Re^2: Clever vs. Readable by Anonymous Monk on Aug 09, 2008 at 17:55 UTC
Only `$result = min($a, $a);` [download] is incorrect, supposed to be `min( $a, $b);` [download]	[reply] [d/l] [select]
Re^2: Clever vs. Readable by Anonymous Monk on Aug 09, 2008 at 17:53 UTC
dems fightin' werds. pleez explain.	[reply]
Re^3: Clever vs. Readable by ikegami (Patriarch) on Aug 09, 2008 at 22:10 UTC
`<=` is not documented to return 1 when true.	[reply] [d/l]
Re^4: Clever vs. Readable by BrowserUk (Patriarch) on Aug 09, 2008 at 23:14 UTC
Re^5: Clever vs. Readable by ikegami (Patriarch) on Aug 10, 2008 at 00:31 UTC
Some notes below your chosen depth have not been shown here
Re^4: Clever vs. Readable by ambrus (Abbot) on Aug 09, 2008 at 23:43 UTC
Re^3: Clever vs. Readable by GrandFather (Saint) on Aug 09, 2008 at 20:54 UTC
Two return a max result. I'll leave you to guess which one is correct. The ternary variant suggested elsewhere suffers somewhat from the same exposure to simple coding errors, especially if the value calculations are not trivial or the size of the set of values being tested is increased. Perl reduces RSI - it saves typing	[reply]
Re^4: Clever vs. Readable by Anonymous Monk on Aug 10, 2008 at 12:35 UTC
Re: Clever vs. Readable by Anonymous Monk on Aug 09, 2008 at 17:56 UTC
Example is so short that it makes no difference (if you call it $min, not $result).	[reply]
Re: Clever vs. Readable by John M. Dlugosz (Monsignor) on Aug 10, 2008 at 05:01 UTC
What's wrong with $result = $a ⌊ $b;	[reply]
Re^2: Clever vs. Readable by JavaFan (Canon) on Aug 10, 2008 at 09:51 UTC
Some reasons why it's wrong in my opinion: I've no idea what vertical bar with a small hook to the bottom right means. It's certainly not a common math symbol. (At least, not on its own. It's a "left floor" symbol, usually used together with a "right floor" symbol, indicating the expression in between is rounded down to the nearest integer). It's a symbol that doesn't display well in my urxvt. And even if it did, it will be awkward to enter in my editor. It doesn't work in perl5.10 or earlier.	[reply]
Re^3: Clever vs. Readable by John M. Dlugosz (Monsignor) on Aug 11, 2008 at 03:50 UTC
I was aluding to this tongue-in-cheek article I had just posted. I think it's a more common symbol than, say, `@list�.*foo`, which is actual Perl 6. At least it has precedent, rather than being something totally new. What is a "urxvt"? After posting, I noticed that it did not show well in the font my browser chose for it. The hook is too small and it is easily confused with a solid vertical bar. So assuming font issues were taken care, what do you think of seeing ⌈$x⌉ to mean round up to an integer using ceiling semantics? Even the well-known `trunc` is not known at a glance to have floor or toward-zero semantics while the synonym ⌊⌋ would be obvious. Even more so in domain-specific notation: why invent a legal identifier name when a symbol or notation is already in use with the intended meaning? —John	[reply] [d/l] [select]
Re^4: Clever vs. Readable by JavaFan (Canon) on Aug 11, 2008 at 08:38 UTC


"be consistent"
	PerlMonks

Clever vs. Readable

Perl as an art

Perl as a craft