NacRE

NacRE is a lightweight, NFA-based regular expression engine that supports a subset of Perl compatible regex (PCRE) syntax.

Supported Syntax

• Literals: a, b, c, etc.
• Escaped Characters: \f, \n, \r, \t, \v
• Wildcards: ., \d, \D, \w, \W, \s, \S,
• Anchors: ^, $, \b
• Quantifiers: *, +, ?, {n}, {n,}, {n,m}
• Alternation: |
• Grouping: ()
• Character Classes: [abc], [^abc], [a-z], [\d\D\w\W\s\S]

Installation

1. Clone the repository:

git clone {this repo}
cd nacre

2. Build the project:

make release

3. Run the executable:

./nacre

Usage

./nacre [OPTIONS] PATTERN INPUT_FILE

The default match mode is find the first match from the start of file to the end of the file.

Options:

• -g: Global matching (find all matches)
• -m: Multiline matching (process input line by line).

Example:

./nacre -gm "a.*b" example.txt

This command matches all occurrences of the pattern a.*b in example.txt with global and multiline options enabled.