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Re: Pattern engine extension for \< and \> support?

Sebastian Gniazdowski wrote on Fri, Jan 27, 2023 at 10:01:15 +0000:
> Hi,
> in regexps, there are \<, \> and also \b sequences, that match zero-length
> string on the word boundary. They are particularly useful for e.g.:
> refactoring substitutions, like e.g.: with sed:
> sed -r -i -e 's/\<myvar\>/other/'
> This automatically protects pre/suffixed strings like str_myvar and
> myvar_str. In mcedit, I often use \b that's available there (\< and \> do
> not work), to obtain the same effect with the regex:
> \bmyvat\b
> I'm not sure if distinction of left and right boundary offered by \<, \>
> actually makes a difference.
> Zsh has similar sequences already - (#s) and (#e). They do match 0=length
> strings on begin or end of the matched string. So maybe the topic is known
> to any implementing person? Is it hard to add such \b or \<,\> sequences?
> Could it be also possible to make it backward-safe, i.e. the sequence be
> ignored by proceeding Zsh versions?

This happens to be covered here:


tl;dr For portability use RE_MATCH_PCRE.

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