Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/kei-k23/rex
Regular Expression (Regex) engine that written in C++
https://github.com/kei-k23/rex
clang cpp regex regular-expression
Last synced: 9 days ago
JSON representation
Regular Expression (Regex) engine that written in C++
- Host: GitHub
- URL: https://github.com/kei-k23/rex
- Owner: Kei-K23
- License: mit
- Created: 2024-08-29T04:14:04.000Z (5 months ago)
- Default Branch: main
- Last Pushed: 2024-08-30T06:32:18.000Z (5 months ago)
- Last Synced: 2024-12-04T16:39:21.087Z (2 months ago)
- Topics: clang, cpp, regex, regular-expression
- Language: C++
- Homepage:
- Size: 65.4 KB
- Stars: 4
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Rex
`Rex` is a `Regular Expression (Regex) engine` that written in `C++`. It supports basic features like matching literal characters, the wildcard (.) character, the Kleene star (\*) for zero or more repetitions, grouping using parentheses (()), lookahead/lookbehind ,and alternation using the pipe (|) operator.
## Features
- **Literal Matching**: Match specific characters in the input string.
- **Wildcard (.)**: Matches any single character.
- **Kleene Star (\_)**: Matches zero or more occurrences of the preceding element.
- **Grouping (())**: Groups expressions to apply operators like \_ or to create sub-expressions.
- **Alternation (|)**: Provides a choice between alternatives, matching either expression.
- **lookahead/lookbehind**: Lookaround assertions are non-capturing groups that return matches only if the target string is followed or preceded by a particular character.
## Usage
### Prerequisites
- C++ compiler (e.g., g++, clang++).
### Building the Project
To compile the project, run the following command:
```bash
clang++ -std=c++20 main.cpp -o rex
# Or
g++ -std=c++20 main.cpp -o rex
```
### Running the Program
You can run the compiled executable with a pattern and text input:
```bash
./regex_engine -p -t
```
#### Example
To match the text "bbc" against the pattern "a|b\*":
```bash
./regex_engine -p "a|b\*" -t "bbc"
```
This will output:
```bash
Match!
```
### Command-Line Arguments
- `-p `: The regular expression pattern to match.
- `-t `: The text to be matched against the pattern.
### Example Patterns
1. `a*b` matches `"ab"`, `"aab"`, `"b"`.
2. `a|b` matches `"a"` or `"b"`.
3. `(ab)*` matches `"ab"`, `"abab"`, `""` (empty string).
4. `a.b` matches `"acb`", `"aab"`, `"a*b"` (where \* represents any character).
## Project Structure
- `main.cpp`: The main implementation file that includes the Lexer, Parser, AST nodes, and Matcher.
### Limitations
- The engine currently supports basic regular expression features and does not handle advanced features like character classes, quantifiers other than \*, or non-greedy matching.
## Future Enhancements
- Add support for character classes (e.g., [a-z]).
- Implement additional quantifiers (+, ?, {min,max}).
- Support for anchors (^, $).
- Enhance the engine to support non-greedy matching.
- Add error handling and more informative messages for invalid patterns.
## License
This project is licensed under the [MIT License](/LICENSE). See the LICENSE file for more details.