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Engineering

Regex Builder

Build a regular expression from a plain-English requirement — explained token by token, tested against sneaky near-misses, with the honest note when regex is the wrong tool.

Write a regular expression that matches: {{requirement}}. Target flavour: {{language}}.

Return: the regex, a token-by-token explanation, 3 strings it matches and 3 it must not — including sneaky near-misses (the almost-valid inputs that expose lazy patterns), the flavour-specific gotchas for {{language}} (escaping, unicode, multiline flags), a hardened version if the naive one is vulnerable to catastrophic backtracking, and the honest check: if this requirement is really parsing (nested structures, HTML, dates with validation), say regex is the wrong tool and name the better one.

Fields like {{ this }} are placeholders — replace them with your own details, or let Aria ask you for them.

regex patterns tools

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