Inline Regex

Inline regexes allow you to embed regular expressions in Pomsky.

Syntax

let InlineRegex = 'regex' String;

Example

regex '(?2)'                # subroutine
regex '[\w--[\p{Latin}]]'   # character set subtraction

Support

Inline regexes are supported in all flavors.

Support for inline regexes is gated by the regexes feature. Specify features with the --allowed-features option.

Behavior

Inline regexes can do anything the targeted regex engine supports. However, inline regexes may not be as portable, because different regex engines use slightly different syntax for some features.

Compilation

The string content is emitted by the compiler verbatim. If the expression is repeated, it is wrapped in a non-capturing group. Pomsky also adds a non-capturing group if the inline regex is surrounded by parentheses. For example:

Pomsky	Compiled regex
regex 'a|b'	a|b
regex 'a|b'+	(?:a|b)+
regex 'a|b' 'c'	a|bc
(regex 'a|b') 'c'	(?:a|b)c

This is the only situation where parentheses affect the compiled regex, even though they do not affect precedence in the Pomsky expression.

Issues

Pomsky doesn’t know when the inline regex needs to be wrapped in a non-capturing group. No group is added when multiple expressions are concatenated, which may be incorrect if the inline regex is an alternation.

History

Initial implementation in Pomsky 0.8