Regex engine
This repository contains a regex engine that can handle basic regex syntax, including literals (a, b, c, etc.), wild-card (.), and metacharacters (?, *, +, ^, $).
The program takes in one string (two elements to be compared must be separated by |). On the left of the delimiter | is the regular expression, and on the right is the string that is being compared to that regular expression.
In the output there is a boolean representing whether the string matches the regex.
Get started!
- download the repository
- run the program in the command-line
RegexEngine > python main.py
Sample usage
Usage of $ and ^:
Input: '^app|apple' Output: True
Input: 'le$|apple' Output: True
Input: '^a|apple' Output: True
Input: '.$|apple' Output: True
Input: 'apple$|tasty apple' Output: True
Input: '^apple|apple pie' Output: True
Input: '^apple$|apple' Output: True
Input: '^apple$|tasty apple' Output: False
Input: '^apple$|apple pie' Output: False
Input: 'app$|apple' Output: False
Input: '^le|apple' Output: False
Usage of ? and *:
Input: 'colou?r|color' Output: True
Input: 'colou?r|colour' Output: True
Input: 'colou?r|colouur' Output: False
Input: 'colou*r|color' Output: True
Input: 'colou*r|colour' Output: True
Input: 'colou*r|colouur' Output: True
Input: 'col.*r|color' Output: True
Input: 'col.*r|colour' Output: True
Input: 'col.*r|colr' Output: True
Input: 'col.*r|collar' Output: True
Input: 'col.*r$|colors' Output: False
Usage of a backward slash (the escape symbol):
Input: '\.$|end.' Output: True
Input: '3\+3|3+3=6' Output: True
Input: '\?|Is this working?' Output: True
Input: '\\|\' Output: True
Input: 'colou\?r|color' Output: False
Input: 'colou\?r|colour' Output: False