How to extract regex matches using Vim

Question

An example:

case Foo:
    ...
    break;
case Bar:
    ...
    break;
case More: case Complex:
    ...
    break:
...

I’d like to retrieve al

Answer 1

How to use vim regex to extract the word from the following line, given that 'help' might be any word like 'rust' or 'perlang'.

vim:tw=78:ts=8:ft=help:norl:

Solution:

let foo = substitute(foo, '^\s*vim:.*:ft=\([a-z]\+\).*:\s*$', '\1', '')
echo "foo: '" . foo . "'"

Prints:

foo: 'help'

Guru meditation: What's going on here?

Take the string in the variable foo and match it to assert the beginning of the line, then any number of spaces, the literal vim and a literal colon, then any number of any characters followed by colon ft= with any word with letters, then anything, and assert the line ends with a colon. Throw all that into a register named 1, then get that back in parameter 2 which substitute takes on and replaces the prior string with.

As a general philosophy, any regex longer than your finger on the screen is an epic fail, so decrease screen resolution until it fits.