On 26 Aug 2019, at 12:13, Umberto Cerrato wrote:

This seems to work too...

[ 'source.*{c, c++, python}' ]

It may seem to work, but it shouldn’t, that is, source.* will match all source documents (as opposed to text.*), the following braces are non-sensical, and the comma will be interpreted as scope selector delimiter.

Either use a file glob or use scope selectors.

For more information about scope selectors I suggest these two resources:

TextMate 1.5.1 manual (but concept is the same for 2.0): https://macromates.com/manual/en/scope_selectors
Blog post: https://macromates.com/blog/2005/introduction-to-scopes/