proc

Presenting the Idiom I found an interesting but unexplained alternative to an accepted answer. The code clearly works in the REPL. For example: module Foo class Bar def baz end end end Foo.constants.map(&Foo.method(:const_get)).grep(Class) => [Foo::Bar] However, I don't fully understand the idiom in use here. In particular, I don't understand the use of &Foo , which seems to be some sort of closure, or how this specific invocation of #grep operates on the result. Parsing the Idiom So far, I've been able to parse bits and pieces of this, but I'm not really seeing how it all fits together. Here

For Fibers we have got classic example: generating of Fibonacci numbers fib = Fiber.new do x, y = 0, 1 loop do Fiber.yield y x,y = y,x+y end end Why do we need Fibers here? I can rewrite this with just the same Proc (closure, actually) def clsr x, y = 0, 1 Proc.new do x, y = y, x + y x end end So 10.times { puts fib.resume } and prc = clsr 10.times { puts prc.call } will return just the same result. So what are the advantages of fibers. What kind of stuff I can write with Fibers I can't do with lambdas and other cool Ruby features? Fibers are something you will probably never use directly in

This question already has an answer here: Code block passed to each works with brackets but not with 'do'-'end' (ruby) 3 answers This doesn't work: run Proc.new do |env| [200, { "Content-Type" => "application/json; charset=UTF-8" }, ["{\"name\":\"Rack App\"}"]] end But this does: run Proc.new { |env| [200, { "Content-Type" => "application/json; charset=UTF-8" }, ["{\"name\":\"Rack App\"}"]] } Any ideas, why its throwing error when used with do..end? Error I am getting: app.ru:1:in new: tried to create Proc object without a block (ArgumentError) Your first code is interpreted as: run(Proc.new)

e.g. x = 123 p = Proc.new { x = 'I do not want change the value of the outer x, I want to create a local x' } In Ruby Is there something the same as "my" keyword in Perl ? As per the Perl documentation of my ,I think you are looking for something like below in Ruby:- x = 123 p = Proc.new {|;x| x = 'I do not want change the value of the outer x, I want to create a local x' } p.call # => "I do not want change the value of the outer x, I want to create a local x" x # => 123 ChrisPhoenix Beware! (Related, though not exactly what you're asking...) The rules for variable scope changed between 1.8

Hello! I wanto to make simple c proggram what will work like ps -e. The only colums that should be shown are PID and CMD. Thats my code: #include <dirent.h> #include <errno.h> #include <sys/types.h> #include <stdio.h> #include <regex.h> int main() { DIR *dir; struct dirent *entry; if ((dir = opendir("/proc")) == NULL) perror("operation error"); else { printf("PID CMD\n"); while ((entry = readdir(dir)) != NULL) printf(" %s\n", entry->d_name); closedir(dir); } return 0; } My questins are: 1) How i can show only folders with numbers(i don't know how to implement regcomp())? 2)How to near PID

i'm trying to get the filesize of the cmdline file in proc/[pid]. For example porc/1/cmdline. The file is not empty, it contains "/sbin/init". But i get file_size = 0. int main(int argc, char **argv) { int file_size; FILE *file_cmd; file_cmd = fopen("/proc/1/cmdline", "r"); if(file_cmd == NULL) { perror("proc/1/cmdline"); exit(1); }else { if(fseek(file_cmd, 0L, SEEK_END)!=0) { perror("proc/1/cmdline"); exit(1); } file_size = ftell(file_cmd); } printf("fs: %d\n",file_size); fclose(file_cmd); } Regards That's normal. /proc files (most of them, there are a few exceptions) are generated by the