Debugging

[FredSRichardson]

Okay, I'm having trouble with "balance_quotes" (in the iwgrules.ml) raising "Invalid_argument(_)". It took me a long time to find this. Here's the snippet (goes back to iwg2 days):

 

let balance_quotes fn s =
 let num_quotes = ref 0 in
 for i = 0 to String.length s do
   if s.[i] = '"' then incr num_quotes
   else if s.[i] = '\'' then (s.[i] <- '"'; incr num_quotes) 
 done;
 if !num_quotes mod 2 <> 0 then begin
   error "DLG" "[%s] has %d quotes in ~%s~: balancing.\n" fn !num_quotes s;
   let s = Str.global_replace left_quote_regexp "\"\\1\"\\2" s in
   let s = Str.global_replace right_quote_regexp "\\1\"\\2\"" s in
   s
 end else s

 

Could it be that the index should only go up to "(String.length s) - 1"?

[the bigg]

Yeah, Ocaml string (like C ones) go from 0 to length - 1.

[FredSRichardson]

This must be an ocaml version problem since the code wasn't breaking until recently (and I bumped my Ocaml to 3.09.1 not so long ago).

[the bigg]

Check if the Makefile defines UNSAFE to 1 or not. WesDU was unsafe, while BiggDU >= 191 is compiled with bounds check, which could cause the problems you described.

[FredSRichardson]

Ah, bounds checking is a good thing! But what a pain to track this down. I had to do a search with print statements to figure out where the routine was exiting early and then add a "try ... with" wrapper to figure out what the exception was. Sheesh! There's got to be a better way.