Tip #282: Folding with Regular Expression

Well, I've tried to understand some of the folding scripts, but life's
too short. Instead, I added the following lines to my vimrc file.

set foldexpr=(getline(v:lnum)=~@/)?0:(getline(v:lnum-1)=~@/)\|\|(getline(v:lnum+1)=~@/)?1:2
map \z :set foldmethod=expr foldlevel=0 foldcolumn=2<CR>

The first line is an extension of foldexpr=(getline(v:lnum)=~@/)?0:1
The second line (re)sets the foldmethod to expr(ession) plus.

First search for /regexp/, then fold everything else with \z
Use zr to reveal more context (before/after) lines.

You could add (getline(v:lnum-2)=~@/)\|\|(getline(v:lnum+2)=~@/)?2:3
but it will take longer as folded lines (the majority) evaluate the full expression.

What could be easier?

<<Stateful zz | Turn on syntax coloring in Mac OS X >>

Additional Notes