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Some things are unavoidable though. Perl hijacking a user space variable to do internal sort management? Bizarre to my mind, and utterly confounding the first t

by bch 6y ago

Some things are unavoidable though. Perl hijacking a user space variable to do internal sort management? Bizarre to my mind, and utterly confounding the first time one accidentally runs into it. [0] https://stackoverflow.com/questions/26127617/what-exactly-are-a-and-b-in-perls-sort-function#26128328 https://stackoverflow.com/questions/26127617/what-exactly-ar...

kbenson 6y ago
That's not so much Perl hijacking a user space variable as Perl having some single character globals that have special behavior. Really, you usually learn about those early (sorting is common), and if you're using strict like you should be, if you define them and use them they will work as expected until you use a custom sort, in which case you'll track down the error. In Perl, you learn pretty early that single character non-alphanumeric variables ($|, $_, @_ $@) are special and if you encounter them and don't know them, look them up. You also learn that $1 through $9 and $a and $b have special uses, so don't use those without knowing what you're doing either. > utterly confounding the first time one accidentally runs into it. Yeah, but every language has some of those. Who remembers "Unexpected T_PAAMAYIM_NEKUDOTAYIM" in PHP? Or giant template error messages in C++? Or just plain segfaults? All paradigms and the languages within them have their own trade-offs and gotchas, and part of learning the language is learning those.
boring_twenties 6y ago
I take it you've never done much shell scripting? This part of perl's baggage comes from its roots as a "better" shell/awk/sed. I don't like it any more than you do, but I must say, I wish people would reserve some of the vitriol they have for perl for the shell. Because I gotta tell you Rabbi, perl is a hell of a lot better than shell scripts. And that's even if you compare perl4 (1991-1994 or so?) to the very latest bash or zsh. edit: BTW if $| is really at risk of clashing with a variable you defined... something else is wrong. :) Compare that with the shell, where names like IFS can do unimaginable things if you don't know about them and set them by mistake. (Or maliciously; it's imported directly from the environment, and stuff like this is why shell scripts can basically never be given untrusted input, whereas perl, with the 'taint' option, can.) Reflecting on all this it's pretty sad that newbies in 2020 are encouraged to learn bash, and continue creating arcane, unreadable, booby-trap-laden scripts in it, all the while looking down their nose at perl.

by bch 6y ago

kbenson 6y ago

That's not so much Perl hijacking a user space variable as Perl having some single character globals that have special behavior. Really, you usually learn about those early (sorting is common), and if you're using strict like you should be, if you define them and use them they will work as expected until you use a custom sort, in which case you'll track down the error. In Perl, you learn pretty early that single character non-alphanumeric variables ($|, $_, @_ $@) are special and if you encounter them and don't know them, look them up. You also learn that $1 through $9 and $a and $b have special uses, so don't use those without knowing what you're doing either. > utterly confounding the first time one accidentally runs into it. Yeah, but every language has some of those. Who remembers "Unexpected T_PAAMAYIM_NEKUDOTAYIM" in PHP? Or giant template error messages in C++? Or just plain segfaults? All paradigms and the languages within them have their own trade-offs and gotchas, and part of learning the language is learning those.

boring_twenties 6y ago

I take it you've never done much shell scripting? This part of perl's baggage comes from its roots as a "better" shell/awk/sed. I don't like it any more than you do, but I must say, I wish people would reserve some of the vitriol they have for perl for the shell. Because I gotta tell you Rabbi, perl is a hell of a lot better than shell scripts. And that's even if you compare perl4 (1991-1994 or so?) to the very latest bash or zsh. edit: BTW if $| is really at risk of clashing with a variable you defined... something else is wrong. :) Compare that with the shell, where names like IFS can do unimaginable things if you don't know about them and set them by mistake. (Or maliciously; it's imported directly from the environment, and stuff like this is why shell scripts can basically never be given untrusted input, whereas perl, with the 'taint' option, can.) Reflecting on all this it's pretty sad that newbies in 2020 are encouraged to learn bash, and continue creating arcane, unreadable, booby-trap-laden scripts in it, all the while looking down their nose at perl.