Are there any good (or at least interesting but flawed) analogs to regular expressions in two dimensions?
In one dimension I can write something like /aaac?(bc)*b?aaa/ to quickly pull out a region of alternating bs and cs with a border of at least three as. Perhaps as importantly, I can come back a month later and see at a glance what it's looking for.
I'm finding myself writing custom code for analogous problems in 2d (some much more complicated / constrained) and it would be nice to have a more concise and standardized notation, even if I have to write the engine behind it myself.
A second example might be called "find the +". The goal is to locate a column of 3 or more as, a b bracketed by 3 or more as with three or more as below. It should match:
..7...hkj.k f
7...a h o j
----a--------
j .a,g- 8 9
.aaabaaaaa7 j
k .a,,g- h j
hh a----? j
a hjg
and might be written as [b^(a{3})v(a{3})>(a{3})<(a{3})] or...
Suggestions?