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regex-visual-debugger

Debug regex patterns with plain English explanations, test cases, and flavor conversion.

1|Updated Aug 8, 2026
Search Tags:#debugging#validation#pattern matching#regex#test cases#regular expressions#flavor conversion
One-click install
npx skills add https://github.com/th-efool/SKILLS --skill regex-visual-debugger-th-efool
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: regex-visual-debugger
Source: https://github.com/th-efool/SKILLS/tree/main/regex-debugger
Command: npx skills add https://github.com/th-efool/SKILLS --skill regex-visual-debugger-th-efool

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Regular expressions are notoriously hard to read and debug. This Skill breaks down any regex pattern into plain English, shows exactly why it matches or fails against test strings, and identifies common mistakes like unescaped characters or greedy quantifier issues. ## Core Features & Use Cases - Pattern Explanation: Decomposes regex into component-by-component plain English descriptions with visual hierarchical breakdowns of groups, quantifiers, and anchors. - Test Case Generation: Creates positive and negative test strings including edge cases and boundary conditions to validate pattern behavior. - Flavor Conversion: Converts patterns between Python, JavaScript, Perl, Java, .NET, and PHP (PCRE) with notes on flavor-specific features like named capture groups. - Use Case: You inherit a complex IP address validation regex like ^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}... and need to understand what it does, verify it works, and port it from Python to JavaScript. ## Quick Start Explain why my regex \w+@\w+.\w+ fails to match the email [email protected] and suggest an improved pattern.

Frequently Asked Questions about regex-visual-debugger

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I debug a regex pattern that is not matching?▼

Break the pattern into components and test each part against your target strings to isolate the failure point. Common causes include unescaped special characters, incorrect quantifiers, misplaced anchors, and greedy versus non-greedy matching issues.

How to convert a Python regex to JavaScript?▼

Identify Python-specific features like named capture groups written as (?P<name>...) and convert them to JavaScript syntax (?<name>...). Also check differences in flags, lookbehind support, and Unicode handling between the two flavors.

Why does my email regex fail on some valid addresses?▼

Simple patterns like \w+@\w+\.\w+ fail on addresses containing plus signs, hyphens, or multi-part TLDs like .co.uk. Expand the character classes to include special characters and handle multiple domain segments.

What is the difference between greedy and non-greedy quantifiers?▼

Greedy quantifiers like .* match as much text as possible, while non-greedy versions like .*? match as little as possible. Greedy matching often causes over-matching when multiple closing delimiters exist in the input string.

Does regex syntax differ between programming languages?▼

Yes, regex flavors differ in features like named groups, lookbehinds, Unicode support, and escape conventions. Python, JavaScript, Perl, Java, .NET, and PCRE each have flavor-specific syntax that may require conversion when porting patterns.

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