In this task you have to write a program that reads a regular expression and generates another program that outputs whether an input string is accepted by that regular expression. The output must be a ...
Stroustrup has recently posted a series of posts debunking popular myths about C++. The fifth myth is: “C++ is for large, complicated, programs only”. To debunk it, he wrote a simple C++ program ...
In the spirit of this xkcd Write a program that plays regex golf with arbitrary pairs of lists. The program should at least attempt to make the regex short, a program that just outputs /^(item1|...
Note: This challenge is now closed. Any future cops' submission will not be considered for the accepted answer. This is to ensure that no one can post a very simple regex in the future that only ...
Similar to our threads for language-specific golfing tips: what are general tricks to shorten regular expressions? I can see three uses of regex when it comes to golfing: classic regex golf ("here ...
I want to try a new type of regex golf challenge, which asks you to solve nontrivial computational tasks with nothing but regex substitution. To make this more possible and less of a chore, you will ...
Within the scope of this question, let us consider only strings which consist of the character x repeated arbitrary number of times. For example: <empty> x xx xxxxxxxxxxxxxxxx (Well, ...
The Problem I have a bunch of regular expressions that I need to use in some code, but I'm using a programming language that doesn't support regex! Luckily, I know that the test string will have a ...
Matthias Goergens has a 25,604-character (down from the original 63,993-character) regex to match numbers divisible by 7, but that includes a lot of fluff: redundant parentheses, distribution (xx|xy|...
There are some pretty cool challenges out there involving regex (Self-matching regex, Regex validating regex) This may well be impossible, but is there a regex that will ONLY match itself? NOTE, ...
For the purpose of this challenge, we say that a regex pattern matches a string if the entire string is matched by the pattern, not just a substring. Given two regex patterns A and B, we say that A ...
Challenge Find the shortest regex that validates, i.e. matches, every possible date in the Proleptic Gregorian calendar (which also applies to all dates before its first adoption in 1582) and does ...
Your mission is to write the shortest valid regular expression that no string can match, empty string included. Submissions must have this form ("literal notation"): /pattern/optional-flags ...
Write a non-trivial regex that matches itself. For example, #.*$ will match a comment outside of a string in python until the end-of-line, and also matches itself in perl regex syntax. Rules: The ...
Find the shortest regex that matches all radioactive elements and nothing else in the Periodic Table of Elements. Radioactive Elements 'Technetium','Promethium','Polonium','Astatine','Radon','...
Because we can't get enough of esoteric language golfs, can we? ///—pronounced slashes—is a fun little language based on the s/// regex-replacement function of Perl fame. It contains only ...
Your task here is to write two regular expressions, each of which matches the other one but does not match itself. Both regular expressions should have this form: /pattern/optional-flags This is ...
Challenge Write the shortest code that can sum all the time durations that appear in the stdin. The program must only consider the strings that match with one of the following patterns and ignore the ...