[slime-devel] Re: More steroids for M-. in CMUCL

[Luke Gorrie]

This is a post about M-. from Alan Ruttenberg which bounced for 
boring mailing list reasons. His idea sounds great to me.   When I 
did something like this for MCL I used to search from the position 
of source the last time the form was compiled, downward, then 
upward on the theory they more often than not I was adding to the 
file. In the earlier version I used the (defxxx heuristic.

For openmcl I've been thinking that I should record the whole text 
(from the source file) of the definition with the function. What 
would be ideal would be to do a fuzzy search for the whole text, 
along the line of a BLAST alignment in genomics and choose the 
best matching position, (or even highlight where your code went in 
the case that you refactored :)

Note that M-. and finding the source location for a given PC in 
the debugger are implemented in almost the same way in this 
scenario. You associate with each PC the bounds of the definition 
form relative to the stored text for the function. Then, within 
the fuzzy match/alignment of the containing function you fuzzy 
match/align the source for the form being evaluated at the PC.

What's holding me back from trying this is having access to a 
fuzzy match algorithm. Does anyone know of one? Or have an idea of 
how to use some diff variant to get the same effect? Inside emacs 
would be ideal but we could also run a shell script on the buffer 
to get the match.

Saving all text and doing lots of computation to navigate to 
source may seem extravagant to some but it seems to me that the 
big bucks are in saving our time.

-Alan