Hi,

Passing "-O" flag to ghc has solved the problem for now. But since a lot more code is yet to be written, I will keep my fingers crossed if the "-O" flag will continue to avoid the "undefined symbol" problem at the link-stage.

Looking at the intermediate code generated by ghc with "-ddump-ds" option, it seems that ghc is generating code that groups functions involved in certain call-chains (whether contributing to recursion or not), difines them in a "__letrec" block, and puts them in a tuple, and generates outer definititons of these functions by using differfent elements in the tuple.

This bug has been fixed, sorry for not noticing before. The fix wasn't merged into 6.0.1, but it will be in 6.2. Cheers, Simon