Standard library

nox.regex

A small regular-expression matcher for simple patterns. It is not a full regex engine: there are no groups, alternation or counted repetition. For anything beyond the subset below, use string methods or write the matching logic directly.

Text

import nox.regex

Capability: none.

Functions#

Function	Description
`is_match(pattern, text)`	whether `pattern` matches anywhere in `text` (only at the start when the pattern begins with `^`)
`find(pattern, text)`	the 0-based byte index where the first match starts, or `-1`

Supported syntax#

Syntax	Meaning
a literal character	matches itself
`.`	any single character
`*`, `+`, `?`	zero or more, one or more, zero or one of the preceding item
`^`, `$`	start / end of the text
`[abc]`, `[a-z]`, `[^abc]`	a character class, a range, a negated class

Not supported: groups ( ) and captures, alternation a|b, back-references, counted repetition {m,n}, and escape classes such as \d or \w (write [0-9] and [a-zA-Z0-9_]).

Nox

import nox.regex

print(nox.regex.is_match("^a.c", "abc"), nox.regex.is_match("b+", "abbbc"), nox.regex.is_match("[0-9]+$", "x12"))
print(nox.regex.find("c", "abc"), nox.regex.find("z", "abc"), nox.regex.is_match("^colou?r$", "color"))

Output

True True True
2 -1 True

Notes#

Matching uses backtracking; avoid patterns with several nested * over large inputs.
The validator in nox.validate uses this module for its pattern rule.

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