6 ms·

Reliability? Sure. Readability? Not so much.

by nthitz 14y ago

pthread 14y ago
Well you know, some people tell me Haskell is readable, others say C++ is readable, I tend to argue.
bengarvey 14y ago
Such a tired argument. Perl has its issues, but you can write unreadable code in any language. Perl is my set of power tools that sit in my basement for weeks until I get them out and fix/make/do something. And what the OP said is correct. I can install new versions and run 10 year old code without issues.
jbert 14y ago
Would you like to post a representative snippet in your favourite lang? I'll try and rewrite in perl and we can compare. (All langs have particular sweet spots, if you do an R or APL oneliner or something it's going to be much more verbose in perl, obviously) It's not that I think perl will be significantly (or at all) nicer, but I think the readability difference is often overstated and I'd like to test that thought.
- afc 14y ago
  Lets see, what about factorial in constant memory? Exponentiation (a to the power of b, where they are positive integers) in logarithmic time (not using built-in exponentiation functions/syntax)? Anonymously add a constant to a number and return it (in a way that can be passed to a function like 'map' or some such)? def Factorial(x): output = 1 for i in xrange(x): output *= (i + 1) return output def Factorial2(x): return reduce(operator.mul, xrange(1, x + 1), 1) I provided two versions, both with constant memory, to show how it'd look with explicit iteration and without it. With this, I get: >>> Factorial(200) 788657867364790503552363213932185062295135977687173263294742533244359449963403342920304284011984623904177212138919638830257642790242637105061926624952829931113462857270763317237396988943922445621451664240254033291864131227428294853277524242407573903240321257405579568660226031904170324062351700858796178922222789623703897374720000000000000000000000000000000000000000000000000L Exponentiation: def Power(a, b): if not b: return 1 if b % 2: return Power(a, b - 1) * a x = Power(a, b/2) return x * x Add a constant: lambda x: x + 7 Or, if you want to name it globally: def TweakValue(x): return x + 7 How do they look in Perl?
  - judofyr 14y ago
    use bignum; use v5.10; =cut def Factorial(x): output = 1 for i in xrange(x): output *= (i + 1) return output =cut # Direct translation sub factorial { my $x = shift; my $output = 1; for my $i (1 .. $x) { $output *= $i; } return $output; } say factorial(200); =cut def Factorial2(x): return reduce(operator.mul, xrange(1, x + 1), 1) =cut use List::Util "reduce"; sub factorial2 { my $x = shift; reduce { $a * $b } (1 .. $x); } say factorial(200); =cut def Power(a, b): if not b: return 1 if b % 2: return Power(a, b - 1) * a x = Power(a, b/2) return x * x =cut sub power { my $a = shift; my $b = shift // return 1; if ($b % 2) { return power($a, $b - 1) * $a } my $x = power($a, $b/2); return $x * $x; } # lambda x: x + 7 my $plus7 = sub { $_[0] + 7 }; # Or: my $plus7 = sub { my $x = shift; $x + 7 }; say $plus7->(14); =cut def TweakValue(x): return x + 7 =cut sub plus7 { $_[0] + 7 } say plus7(14);
    - colomon 14y ago
      Just in case anyone was wondering, in Perl 6: sub factorial($n) { my $output = 1; for 1..$n -> $i { $output *= $i; } $output; } or sub factorial2($n) { [*] 1..$n; } Pretty anonymous function to add a constant: -> $x { $x + 7 } Really short version: * + 7 Named: sub plus7($x) { $x + 7; }
  - jbert 14y ago
    Thanks for that. First one (not 100% sure it's constant memory, I think perl optimises the for to avoid instantiating the (1..$n) list: #!/usr/bin/perl use Modern::Perl; use bigint; say fact(5000); sub fact { my ($n) = @_; my $output = 1; for my $i (1..$n) { $output *= $i; } return $output; } (Took the value up to 5000 to get something which ran long enough to get a measurement, on my laptop it runs (including startup time) in ~1.2s. (Can we compare runtime too? I know we're discussing readability, but I'm interested). The reduce version (again, I'm unsure of const mem req). Comes in at ~1.4s: #!/usr/bin/perl use Modern::Perl; use List::Util qw(reduce); use bigint; say fact(5000); sub fact { my ($n) = @_; return reduce(sub { $a * $b; }, 1, (1..$n)); } The add a constant (true lambda, closing over lexicals in scope, etc etc) is 'sub': sub { my ($x) = @_; $x + 7; } (doesn't have the python lambda limitations). (Be aware that perl GC is refcounted though, so ref cycles are possible). Edit: I think the languages are comparable in terms of features and also readability. People may dislike leading sigils and that's fair, but I dislike python's "no need to declare your vars, just hope you don't typo an assignment" approach to lexicals.
pwaring 14y ago
You can write readable Perl, just like you can write secure PHP. The fact that a large number of people don't is not necessarily a failing of the language.
- TylerE 14y ago
  Disagree. Readability and reasonable shoot-self-in-foot protection are not optional. See the article from earlier today about not catering to power users. Same concept. You can't really design a language for the top 5% of programmers and expect it to gain any sort of acceptance. (See: Haskell, Ocaml)
  - dasil003 14y ago
    Are regexps readable? Is sed/awk readable? xpath? Perl is a power tool. The reason it can be unreadable is because of it's terse syntax, wherein resides its power. If you value readability above power then you choose Java, and I would agree that for a large enterprise app developed by an army of mediocre developers then Java is surely the better choice. However to judge the absolute merits of a language like Perl on reputed readability, without taking into consideration what its terseness allows, and how it works for large scale development given a sane coding standard is just burying your head in the sand.
  - kamaal 14y ago
    In that case you are likely to never like any form of string/data/text processing. Unless it is provided you through an interface of a database, XML or JSON. And there are plenty of tools designed to handle data from such interfaces. You will be shocked how few tools are there for the other kind of data.
  - papsosouid 14y ago
    I completely agree with your first statement, but I have no idea how you get to your final statement from that. Ocaml and haskell are both on the "shoot self anywhere protection" end of the language spectrum. I used ocaml for a couple years and program in haskell for a living, and I assure you I am not in the top 5% of programmers.
zeeone 14y ago
The favorite argument of the weak programmer. Some people act like if it's not spelled out for them letter by letter it's not readable. Perl is no less readable then HTML5, given that there is proper indentation. Get over it.
- zzzcpan 14y ago
  I think reliability implies readability and even impossible without it.
ajross 14y ago
This is getting rapidly less true. Perl used to get dinged for having "funny" syntax like the prefix glyphs on variables, infix if, etc... That was in a world where the language mindshare was dominated by Java, which made its name by simplifying C++ and not making any weird or unconventional choices in syntax. These days all the cool languages have funny syntax (hell, Ruby lifted most of perl's weirdness directly), sometimes (as with coffeescript) it's touted as a feature. So go back and look at perl with modern eyes. I think you'll find most of the conventional wisdom about its readability was more about the conventions than the wisdom.
- lmm 14y ago
  The feel I get from the "scala community" is that we've realised that fancy operators are a mistake; most operations are better expressed as english words rather than the ~/s of our foolish youth. I wonder if we'll see that happen with other upcoming languages.
mhd 14y ago
Beyond the "You can write Fortran in any language" argument about properly structuring your code, there is a certain amount of truth in this. But in my opinion, this is mostly about familiarity. It's like a human language that uses another alphabet. Sure, if your native language is English, Polish looks more readable than Russian, as the latter is using a different alphabet. But that's a literally superficial point of view (cf. Lisp's parens), a stepping stone that is easily surmounted and doesn't change the total learning curve a lot. English does look simpler than French, too. On the other hand, once you get beyond the accents, you know how to pronounce French, whereas that's not the case with English (cf. "ghoti"). Personally, I never was that bothered by e.g. the type characters, and quite often they were quite helpful about the context expected/required. But then again, I'm German, so maybe growing up with a somewhat ridiculous grammar and Funky Capitalization helped (there's a Perl module that allows you to write code in Latin, and here the cases and other grammatical structures replace the funky characters). Perl certainly has its weaknesses. Some operations should probably be bound to types/objects instead of C-like functions, references are often difficult to untangle and the default object system ain't that grand (on the other hand: Moose). But I've yet to find a language that doesn't have similar weaknesses. Due to the somewhat funky syntax, they're just quite obvious. What does that dollar sign right there indicate? On what default variable is this code operating? Schwartzian what? But I would call that "traceability" issues. And this certainly also happens with macros, meta-programming, complicated object hierarchies, generators, decorators, DoI containers, etc. It probably does matter for casual programmers, i.e. people who don't work 20+ hours/week in Perl. Sysadmins come to mind. But if your involvement with the language is beyond that, I think "readability" is quite often a matter of taste, not more. Which, of course, doesn't totally disqualify this argument. It's just more a matter of rap vs. punk, not junk food vs. rucola salad.
- sbmassey 14y ago
  The 'ghoti can be pronounced as fish' thing is a bit unfair to English orthography, where you must take the surroundings of the letter cluster into account.
  - mhd 14y ago
    The word itself is basically a joke, sure, but it serves as a nice accumulation of letters that have a somewhat unexpected pronunciation, certainly a feature of the English language. Pronunciation and emphasis are pretty hard for non-native speakers, and the written form doesn't help that much. On the other hand of the Latin alphabet spectrum, there are languages like Vietnamese, where you've got a boatload of accents and diacritical marks to help with it. Although I'm not sure whether describing Perl as the Vietnamese of programming languages would be a good selling point, so I'll stick with French ;)
gatlin 14y ago
This is such a tired comment. Just once I'd love to see someone provide an explanation or proof of this assertion.

Reliability? Sure. Readability? Not so much.

by nthitz 14y ago

Reliability? Sure. Readability? Not so much.

pthread 14y ago

Well you know, some people tell me Haskell is readable, others say C++ is readable, I tend to argue.

bengarvey 14y ago

Such a tired argument. Perl has its issues, but you can write unreadable code in any language. Perl is my set of power tools that sit in my basement for weeks until I get them out and fix/make/do something. And what the OP said is correct. I can install new versions and run 10 year old code without issues.

jbert 14y ago

Would you like to post a representative snippet in your favourite lang? I'll try and rewrite in perl and we can compare. (All langs have particular sweet spots, if you do an R or APL oneliner or something it's going to be much more verbose in perl, obviously) It's not that I think perl will be significantly (or at all) nicer, but I think the readability difference is often overstated and I'd like to test that thought.

afc 14y ago
Lets see, what about factorial in constant memory? Exponentiation (a to the power of b, where they are positive integers) in logarithmic time (not using built-in exponentiation functions/syntax)? Anonymously add a constant to a number and return it (in a way that can be passed to a function like 'map' or some such)? def Factorial(x): output = 1 for i in xrange(x): output *= (i + 1) return output def Factorial2(x): return reduce(operator.mul, xrange(1, x + 1), 1) I provided two versions, both with constant memory, to show how it'd look with explicit iteration and without it. With this, I get: >>> Factorial(200) 788657867364790503552363213932185062295135977687173263294742533244359449963403342920304284011984623904177212138919638830257642790242637105061926624952829931113462857270763317237396988943922445621451664240254033291864131227428294853277524242407573903240321257405579568660226031904170324062351700858796178922222789623703897374720000000000000000000000000000000000000000000000000L Exponentiation: def Power(a, b): if not b: return 1 if b % 2: return Power(a, b - 1) * a x = Power(a, b/2) return x * x Add a constant: lambda x: x + 7 Or, if you want to name it globally: def TweakValue(x): return x + 7 How do they look in Perl?
- judofyr 14y ago
  use bignum; use v5.10; =cut def Factorial(x): output = 1 for i in xrange(x): output *= (i + 1) return output =cut # Direct translation sub factorial { my $x = shift; my $output = 1; for my $i (1 .. $x) { $output *= $i; } return $output; } say factorial(200); =cut def Factorial2(x): return reduce(operator.mul, xrange(1, x + 1), 1) =cut use List::Util "reduce"; sub factorial2 { my $x = shift; reduce { $a * $b } (1 .. $x); } say factorial(200); =cut def Power(a, b): if not b: return 1 if b % 2: return Power(a, b - 1) * a x = Power(a, b/2) return x * x =cut sub power { my $a = shift; my $b = shift // return 1; if ($b % 2) { return power($a, $b - 1) * $a } my $x = power($a, $b/2); return $x * $x; } # lambda x: x + 7 my $plus7 = sub { $_[0] + 7 }; # Or: my $plus7 = sub { my $x = shift; $x + 7 }; say $plus7->(14); =cut def TweakValue(x): return x + 7 =cut sub plus7 { $_[0] + 7 } say plus7(14);
  - colomon 14y ago
    Just in case anyone was wondering, in Perl 6: sub factorial($n) { my $output = 1; for 1..$n -> $i { $output *= $i; } $output; } or sub factorial2($n) { [*] 1..$n; } Pretty anonymous function to add a constant: -> $x { $x + 7 } Really short version: * + 7 Named: sub plus7($x) { $x + 7; }
- jbert 14y ago
  Thanks for that. First one (not 100% sure it's constant memory, I think perl optimises the for to avoid instantiating the (1..$n) list: #!/usr/bin/perl use Modern::Perl; use bigint; say fact(5000); sub fact { my ($n) = @_; my $output = 1; for my $i (1..$n) { $output *= $i; } return $output; } (Took the value up to 5000 to get something which ran long enough to get a measurement, on my laptop it runs (including startup time) in ~1.2s. (Can we compare runtime too? I know we're discussing readability, but I'm interested). The reduce version (again, I'm unsure of const mem req). Comes in at ~1.4s: #!/usr/bin/perl use Modern::Perl; use List::Util qw(reduce); use bigint; say fact(5000); sub fact { my ($n) = @_; return reduce(sub { $a * $b; }, 1, (1..$n)); } The add a constant (true lambda, closing over lexicals in scope, etc etc) is 'sub': sub { my ($x) = @_; $x + 7; } (doesn't have the python lambda limitations). (Be aware that perl GC is refcounted though, so ref cycles are possible). Edit: I think the languages are comparable in terms of features and also readability. People may dislike leading sigils and that's fair, but I dislike python's "no need to declare your vars, just hope you don't typo an assignment" approach to lexicals.

pwaring 14y ago

You can write readable Perl, just like you can write secure PHP. The fact that a large number of people don't is not necessarily a failing of the language.

TylerE 14y ago
Disagree. Readability and reasonable shoot-self-in-foot protection are not optional. See the article from earlier today about not catering to power users. Same concept. You can't really design a language for the top 5% of programmers and expect it to gain any sort of acceptance. (See: Haskell, Ocaml)
- dasil003 14y ago
  Are regexps readable? Is sed/awk readable? xpath? Perl is a power tool. The reason it can be unreadable is because of it's terse syntax, wherein resides its power. If you value readability above power then you choose Java, and I would agree that for a large enterprise app developed by an army of mediocre developers then Java is surely the better choice. However to judge the absolute merits of a language like Perl on reputed readability, without taking into consideration what its terseness allows, and how it works for large scale development given a sane coding standard is just burying your head in the sand.
- kamaal 14y ago
  In that case you are likely to never like any form of string/data/text processing. Unless it is provided you through an interface of a database, XML or JSON. And there are plenty of tools designed to handle data from such interfaces. You will be shocked how few tools are there for the other kind of data.
- papsosouid 14y ago
  I completely agree with your first statement, but I have no idea how you get to your final statement from that. Ocaml and haskell are both on the "shoot self anywhere protection" end of the language spectrum. I used ocaml for a couple years and program in haskell for a living, and I assure you I am not in the top 5% of programmers.

zeeone 14y ago

The favorite argument of the weak programmer. Some people act like if it's not spelled out for them letter by letter it's not readable. Perl is no less readable then HTML5, given that there is proper indentation. Get over it.

zzzcpan 14y ago
I think reliability implies readability and even impossible without it.

ajross 14y ago

This is getting rapidly less true. Perl used to get dinged for having "funny" syntax like the prefix glyphs on variables, infix if, etc... That was in a world where the language mindshare was dominated by Java, which made its name by simplifying C++ and not making any weird or unconventional choices in syntax. These days all the cool languages have funny syntax (hell, Ruby lifted most of perl's weirdness directly), sometimes (as with coffeescript) it's touted as a feature. So go back and look at perl with modern eyes. I think you'll find most of the conventional wisdom about its readability was more about the conventions than the wisdom.

lmm 14y ago
The feel I get from the "scala community" is that we've realised that fancy operators are a mistake; most operations are better expressed as english words rather than the ~/s of our foolish youth. I wonder if we'll see that happen with other upcoming languages.

mhd 14y ago

Beyond the "You can write Fortran in any language" argument about properly structuring your code, there is a certain amount of truth in this. But in my opinion, this is mostly about familiarity. It's like a human language that uses another alphabet. Sure, if your native language is English, Polish looks more readable than Russian, as the latter is using a different alphabet. But that's a literally superficial point of view (cf. Lisp's parens), a stepping stone that is easily surmounted and doesn't change the total learning curve a lot. English does look simpler than French, too. On the other hand, once you get beyond the accents, you know how to pronounce French, whereas that's not the case with English (cf. "ghoti"). Personally, I never was that bothered by e.g. the type characters, and quite often they were quite helpful about the context expected/required. But then again, I'm German, so maybe growing up with a somewhat ridiculous grammar and Funky Capitalization helped (there's a Perl module that allows you to write code in Latin, and here the cases and other grammatical structures replace the funky characters). Perl certainly has its weaknesses. Some operations should probably be bound to types/objects instead of C-like functions, references are often difficult to untangle and the default object system ain't that grand (on the other hand: Moose). But I've yet to find a language that doesn't have similar weaknesses. Due to the somewhat funky syntax, they're just quite obvious. What does that dollar sign right there indicate? On what default variable is this code operating? Schwartzian what? But I would call that "traceability" issues. And this certainly also happens with macros, meta-programming, complicated object hierarchies, generators, decorators, DoI containers, etc. It probably does matter for casual programmers, i.e. people who don't work 20+ hours/week in Perl. Sysadmins come to mind. But if your involvement with the language is beyond that, I think "readability" is quite often a matter of taste, not more. Which, of course, doesn't totally disqualify this argument. It's just more a matter of rap vs. punk, not junk food vs. rucola salad.

sbmassey 14y ago
The 'ghoti can be pronounced as fish' thing is a bit unfair to English orthography, where you must take the surroundings of the letter cluster into account.
- mhd 14y ago
  The word itself is basically a joke, sure, but it serves as a nice accumulation of letters that have a somewhat unexpected pronunciation, certainly a feature of the English language. Pronunciation and emphasis are pretty hard for non-native speakers, and the written form doesn't help that much. On the other hand of the Latin alphabet spectrum, there are languages like Vietnamese, where you've got a boatload of accents and diacritical marks to help with it. Although I'm not sure whether describing Perl as the Vietnamese of programming languages would be a good selling point, so I'll stick with French ;)

gatlin 14y ago

This is such a tired comment. Just once I'd love to see someone provide an explanation or proof of this assertion.