Lua pattern matching for empty string

Question

after trying and reading Lua's doc on patterns, I couldn't figure it out.

I am using an OBS plugin to activate a source on text document change, and the plugin uses Lua pattern matching. I would like to trigger the source whenver the document is EMPTY and only empty. How can I go about doing this?

Example, using the non-empty pattern match:

Thank you for any help!

Wiktor Stribiżew · Accepted Answer · 2021-03-09 16:29:37Z

1

Pattern matching an empty string is

^$

where

^ - matches the start of string position
$ - matches the end of string position.

That is, start and end of string positions must be the same position in the string.

answered Mar 9, 2021 at 16:29

Wiktor Stribiżew

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2 Comments

lhf Over a year ago

Or simply s == "".

Wiktor Stribiżew Over a year ago

@lhf I understand there is no actual code access from the plugin, only a field that accepts a pattern string.

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