Interesting problem last night: I wanted to find out how far it was
between a bunch of places. I had the location post codes buried away
in a stack of form letters in pdf form. So convert those to text,
open in emacs and extract the post codes. I couldn't get multi-line
replace-regexp to work,
re-builder successfully highlighted the
replace-regexp failed to match the same regex. Oh well, I
just want to hack this out so keyboard macros did the job.
A quick google later and I came up with the static maps API
so threw the post codes at that to get back a JSON object with all the
distances. Then using json.el in ielm, convert that to a lisp
structure, pick that apart to extract the relevant fields and run my
calculations over that, plotting the results using R in org-mode.
We have some fantastic tools at our disposal: this is a fun game.
So, back to the multi-line regex that fails. I've got an input file in
a 1 b a 2 b
and want to match the paragraph a..b Using
re-builder I can construct
a regex that matches:
But using that regex in
replace-regex results in no matches.
Digging in to this it turns out that, because I'm using replace-regexp
interactively the escaping rules are slightly different: I only need a
single backslash before the brackets.
When is a solution good enough? The keyboard macro approach did the
job quickly and easily. I then spent longer trying to debug the
multi-line regexp than it would have taken me to solve the original
problem by hand. But I learnt something in the process so surely that
is time well invested. Besides it was fun!