1 at the end of a module means that the module returns true to use/require statements. It can be used to tell if module initialization is successful. Otherwise, use/require will fail. $somevar is a variable which is accessable only inside the block. It is used to simulate “static” variables. Starting from Perl 5.10 you can … Read more
My preferred way is: $x_num = oct(“0b” . $x_bin); Quoting from man perlfunc: oct EXPR oct Interprets EXPR as an octal string and returns the corresponding value. (If EXPR happens to start off with “0x”, interprets it as a hex string. If EXPR starts off with “0b”, it is interpreted as a binary string. Leading … Read more
I believe the proper way to do this is to use natatime, from List::MoreUtils: from the docs: natatime BLOCK LIST Creates an array iterator, for looping over an array in chunks of $n items at a time. (n at a time, get it?). An example is probably a better explanation than I could give in … Read more
It’s normal behaviour of the language. Quoting the perlsyn manpage: The number 0, the strings ‘0’ and “”, the empty list (), and undef are all false in a boolean context. All other values are true. Negation of a true value by ! or not returns a special false value. When evaluated as a string … Read more
From ECMAScript 2018 onwards, many of JavaScript’s regex deficiencies have been fixed. It now supports lookbehind assertions, even unbounded ones. Unicode property escapes have been added. There finally is a DOTALL (/s) flag. What is still missing: JavaScript doesn’t have a way to prevent backtracking by making matches final (using possessive quantifiers ++/*+/?+ or atomic … Read more
It may be relevant that Perl never gives memory back to the system by itself: It’s all up to malloc() and all the rules associated with that. Knowing how malloc() allocates memory is important to answering the greater question, and it varies from system to system, but in general most malloc() implementations are optimized for … Read more
Install PAR::Packer from CPAN (it is free) and use pp utility.
There is no perl6, and there are many Perl 6 compilers. Perl 6 has a grammar, although it’s written in Perl 6, so as long as you can understand that, it tells you everything you need to know. I just asked Larry this question, since I’m sitting across from him at lunch at the São … Read more
The answers above are all correct, but it might come across more plainly if you understand general UNIX command line usage. It is very common to want a command to work on multiple files. E.g. ls -l *.c The command line shell (bash et al) turns this into: ls -l a.c b.c c.c … in … Read more
The __LINE__ literal is documented in the Special Literals section of the perldata man page. print “File: “, __FILE__, ” Line: “, __LINE__, “\n”; or warn(“foo”);