Fixed bug in d_error where tok pointers to string l was used outside
its scope.
Fixed D_HASH argument order in comments.
The implementation of val evaluates i twice, so these won't work:
val(a, len(a), int) = 5
val(a, i++, int) = 5
This is a serious bug.  Until resolved use plain variables for index only.
Added some debug code to investigate darr_t in debugger.
Fixed bug with val which was evaluating its second argument twice.