Re: [Haskell-cafe] Debugging partial functions by the rules

Couldn't we just use rewrite rules to rewrite *transparently* all uses of fromJust to safeFromJust, tagging the call site with a location? .. Looks good! But that is deceiving: the assert was expanded before the rule fired, and refers to the rewrite rule source line (line 19), not the fromJust call site (line 12). Now if we could just have the 'assert' token inserted into the AST before it was expanded, we'd be home and dry. Could this be done with TH? Or could we arrange for asserts in rewrite rules not to be expanded till later? .. Any ideas?

http://www.haskell.org/pipermail/glasgow-haskell-users/2006-November/011545.... claus