I frequently find myself trying to do transformations like
author = {{foo
bar}},
to
author = {foo
bar},
and I can't find a regex to match the part in between the curly braces.
%s/{{\(.*\)}}/{\1}/g
doesn't work since . does not match newlines. But [\.\r] or something doesn't seem to work either. I tried [\s\S] as well to match whitespace and non-whitespace, but to no avail.
You should use \_.\{-} instead of .*.
\_. matches any character including end-of-line. However, as :h \_. warns, using it with * will match all text to the end of the buffer.
\{-} is similar to *, matching 0 or more instances of the proceeding atom. But it matches as few as possible instead of as many as possible. This makes \{-} safe if your example pattern appears more than once. For example:
author = {{foo
bar}},
editor = {{buz
baz}},
Using %s/{{\(\_.*\)}}/{\1}/g changes the starting double brace for author, but the closing double brace for editor. Since * matches as many atoms as possible, the pattern matches until the last double brace it finds. This results in the following:
author = {foo
bar}},
editor = {{buz
baz},
However, using %s/{{\(\_.\{-}\)}}/{\1}/g gives the desired result for both author and editor as it stops searching at the first double brace it finds:
author = {foo
bar},
editor = {buz
baz},
Turns out one must use \_.* instead of ..
ds{