RePoet: Write Regular Expressions Like Poetry in Python

🎯 Transform regex into poetry! Write regular expressions as elegantly as writing verses.

✨ Highlights

from repoet import op

# Traditional regex (hard to maintain)
date_regex = r"^(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})$"

# With RePoet (self-documenting and maintainable)
date = op.seq(
    op.begin,
    op.group(op.digit * 4, name="year") + "-",
    op.group(op.digit * 2, name="month") + "-",
    op.group(op.digit * 2, name="day"),
    op.end
)

match = date.match("2024-03-01")
print(match.group("year"))   # "2024"
print(match.group("month"))  # "03"
print(match.group("day"))    # "01"

🚀 Why RePoet?

• 🎭 Full Re API Compatibility - All re module features are supported
• 🎨 Operator Magic - Use +, |, * to compose patterns naturally
• 📝 Multiple Styles - Choose between operator style or functional style
• 🛡️ Type-Safe - Full type hints for better IDE support
• 🎯 Zero Learning Curve - If you know regex, you know RePoet

💫 Quick Start

pip install repoet

📖 Core Concepts

Pattern Composition

from repoet import op

# Using operators
pattern = op.digit + op.word + op.space    # \d\w+\s
pattern = op.digit | op.word               # (?:\d|\w+)
pattern = op.digit * 3                     # \d{3}

# Using functions
pattern = op.seq(op.digit, op.word, op.space)
pattern = op.alt(op.digit, op.word)
pattern = op.times(3)(op.digit)

Named Groups & Captures

# Match phone numbers with named groups
phone = op.seq(
    op.maybe("+"),
    op.group(op.digit * 2, "country"),
    " ",
    op.group(op.digit * 3, "area"),
    "-",
    op.group(op.digit * 4, "number")
)

match = phone.match("+86 123-4567")
print(match.group("country"))  # "86"
print(match.group("number"))   # "4567"

Advanced Features

# Lookarounds
price = op.behind("$") + op.digit * 2      # (?<=\$)\d{2}
not_end = op.word + op.not_ahead(op.end)   # \w+(?!$)

# Character Classes
username = op.some(op.anyof("a-zA-Z0-9_"))  # [a-zA-Z0-9_]+
not_digit = op.exclude("0-9")               # [^0-9]

# Quantifiers
optional = op.maybe("s")                    # s?
one_plus = op.some(op.letter)               # \w+
any_amount = op.mightsome(op.space)         # \s*

🎯 Pattern API

RePoet patterns support all standard re module methods:

pattern = op.word + "@" + op.word

# All re module methods are available
pattern.match(string)
pattern.search(string)
pattern.findall(string)
pattern.finditer(string)
pattern.sub(repl, string)
pattern.split(string)

📚 More Examples

URL Parser

url = op.seq(
    op.group(op.alt("http", "https"), "protocol"),
    "://",
    op.group(op.some(op.anyof("a-z0-9.-")), "domain"),
    op.group(op.mightsome(op.anyof("/a-z0-9.-")), "path")
)

Date Validator

date = (op.digit * 4) + "-" + \
       (op.digit * 2) + "-" + \
       (op.digit * 2)

🧪 Experimental Features

Pattern Indexing

from repoet import op

# Using indexing for quantifiers
pattern[n]     # Exactly n times {n}
pattern[n:]    # n or more times {n,}
pattern[:n]    # Up to n times {,n}
pattern[m:n]   # Between m and n times {m,n}
pattern[:]     # Zero or more times (*)
pattern[1:]    # One or more times (+)
pattern[0:1]   # Zero or one time (?)

# Example
username = op.letter[1:] + op.anyof("._-")[0:1] + op.letter[:]  
# Shorter than: op.some(op.letter) + op.maybe(op.anyof("._-")) + op.mightsome(op.letter)

Note: Pattern indexing is an experimental feature and its behavior might change in future releases.

🤝 Contributing

Contributions are welcome! Feel free to:

• Report bugs
• Suggest features
• Submit pull requests

📜 License

This project is licensed under the MIT License - see the LICENSE file for details.

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⭐️ If you find RePoet useful, please star it on GitHub! ⭐️