Regexlike

Regexlike describes a family of pattern-matching syntaxes that resemble regular expressions but do not constitute the full regex standard. The term is used informally to refer to lightweight or domain-specific regex-like syntax implemented in programming languages, config formats, query languages, and text-processing tools. It emphasizes familiar concepts such as literals, classes, repetition, grouping, and alternation, while omitting or altering more advanced regex features.

Common features include literal characters; character classes (e.g., [a-z]); quantifiers like *, +, ?, and {n,m}; grouping with parentheses; alternation with |; and anchors such as ^ and $. Some implementations also support escaping, basic grouping, and non-capturing groups. The exact syntax and capabilities vary by host environment, and some systems use a simplified engine intended for quick matching rather than complex parsing.

Differences from full regular expressions often center on limited functionality. Regexlike engines may exclude backreferences, lookaround assertions, or possessive quantifiers; escaping rules may be simpler or inconsistent; Unicode support may be partial. Because of these omissions, patterns are typically easier to read and safer to execute, but may be unable to express certain complex patterns.

Uses include search filters in text editors, log parsers, simple validation, and configuration languages. It is also common in DSLs that require pattern matching without introducing a full regex engine. The term underscores the idea that the syntax closely follows regex intuition while leaving room for implementation-specific deviations.