https://github.com/gsingh93/regex-parser

A recursive descent parser for basic regular expressions in Rust
https://github.com/gsingh93/regex-parser

Last synced: 8 days ago
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A recursive descent parser for basic regular expressions in Rust

• Host: GitHub
• URL: https://github.com/gsingh93/regex-parser
• Owner: gsingh93
• Created: 2015-03-11T18:57:57.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-03-19T23:02:57.000Z (over 9 years ago)
• Last Synced: 2024-10-31T11:39:37.585Z (15 days ago)
• Language: Rust
• Size: 145 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Regex Parser

This is a recursive descent parser written in Rust for regular expresssions. Given a regular expression as input, it outputs an AST. It follows this very simple LL(1) grammar:

```

 ::=  '|' 

         |  

 ::= {  }

 ::=  { '*' }

 ::= 

        |  '('  ')'

```

## Usage

```

let mut p = RegExParser::new("((a|b*)|a*)|aab".to_string());

let res = Ok(Or(

    Box::new(Sequence(vec![Box::new(Or(

        Box::new(Sequence(

            vec![Box::new(Or(Box::new(Sequence(vec![Box::new(Terminal('a'))])),

                             Box::new(Sequence(

                                 vec![Box::new(Repetition(Box::new(Terminal('b'))))]))))])),

        Box::new(Sequence(vec![Box::new(Repetition(Box::new(Terminal('a'))))]))))])),

    Box::new(Sequence(vec![Box::new(Terminal('a')), Box::new(Terminal('a')),

                           Box::new(Terminal('b'))]))));

assert_eq!(p.parse(), res);

 ```