Regular Expression Engine

Pattern matching with stated semantics and no catastrophic surprises.

17 capabilities 1 sections reference specification

Build against it

# give your agent the catalog — no account, no install
claude mcp add provespec -- npx -y provespec-mcp

# then, from any agent session
spec_get(slug: "regex-engine")                → the capability tree
spec_checklist(slug: "regex-engine")          → the questions to answer
spec_grade(slug: "regex-engine", grades: [...])  → parity % + the gap list

# or just fetch it
curl https://provespec.com/catalog/regex-engine/spec.json

Grade every capability below as yes · partial · no · na, with a file reference as evidence. Whatever you leave ungraded counts as missing — the gap list is the work queue.

Or just paste this to your agent

Use the ProveSpec MCP server. Fetch the "regex-engine" spec with
spec_get, then walk spec_checklist and grade this repository against it —
one verdict per capability, each with a file reference as the note.
Call spec_grade with the results and give me the gap list as the plan.

If the server is not registered, add it first:
  claude mcp add provespec -- npx -y provespec-mcp

The specification

AI 17

Syntax

✓ Literals, character classes and predefined classes \d \w \s
✓ Quantifiers, greedy and lazy * + ? {n,m} and ?
✓ Alternation and grouping
✓ Anchors and word boundaries ^ $ \b

Groups

✓ Capturing and non-capturing groups
✓ Named capture groups
✓ Backreferences or a documented refusal, for linear-time engines

Lookaround

✓ Lookahead and lookbehind, positive and negative

Flags

✓ Case-insensitive, multiline, dot-all, global, unicode

Unicode

✓ Code-point semantics, not code units
✓ Unicode property escapes \p{L}

API

✓ Test, match, match-all, replace and split
✓ Replacement with group references and a function
✓ Match position and captured spans

Safety

✓ Backtracking bound or a linear-time algorithm ReDoS is a documented concern
✓ Compilation errors report the offending position

Performance

✓ Compiled patterns cached and reusable

Download spec.json All 71 specs