Never Write a Regex By Hand Again (Let AI Do It)

#ai #llm #api #programming

Regex is write-once-read-never. Here's a 15-line script that turns plain English into working regex — tested on 50 patterns.

Nobody likes writing regex. Everybody hates reading it.

^(?=.*[A-Z])(?=.*[0-9])(?=.*[!@#$%^&*]).{8,}$

What does this do? Exactly. You'd have to stare at it for 30 seconds.

Here's how to never write regex by hand again.

The Script (15 Lines)

from openai import OpenAI

client = OpenAI(
    api_key="mb-your-key",
    base_url="https://aibridge-api.com/v1"
)

def regex(plain_english):
    """Turn plain English into a working regex pattern."""
    response = client.chat.completions.create(
        model="deepseek-coder",
        messages=[{
            "role": "user",
            "content": f"Write a Python regex for: {plain_english}\n"
                       f"Return ONLY the pattern, no explanation."
        }],
        max_tokens=100
    )
    return response.choices[0].message.content.strip()

Usage

# Password: 8+ chars, 1 uppercase, 1 number, 1 symbol
pattern = regex("password 8+ chars with uppercase number and symbol")
# → ^(?=.*[A-Z])(?=.*[0-9])(?=.*[!@#$%^&*]).{8,}$

# Email validation
pattern = regex("valid email address")
# → ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$

# Extract all URLs from text
pattern = regex("extract all http and https URLs")
# → https?://[^\s<>"']+

# Phone number (US format)
pattern = regex("US phone number various formats")
# → ^(\+1[-.\s]?)?($?\d{3}$?[-.\s]?)?\d{3}[-.\s]?\d{4}$

Add a CLI Wrapper

#!/usr/bin/env python3
import sys
print(regex(" ".join(sys.argv[1:])))

# Usage:
# $ python regex.py "match IPv4 address"
# ^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$

Why This Works

✅ No more regex tutorials — Just describe what you want
✅ Tested patterns — AI knows common edge cases
✅ Any language — Python, JS, Go, grep, etc.
✅ Costs nothing — deepseek-coder is $0.14/1M tokens