On Wed, Oct 5, 2011 at 5:13 PM, Jay McCarthy <[email protected]> wrote: > > Basically, it calls the app function on the second element of the list > even though the head of the list has failed to pattern match.
This is not a bug. `match' makes no guarantee about the order in which it checks elements of the pattern. If it were to try to support this kind of use case, it would have to specify how many times it would call each function that might be embedded in a match, which requires a detailed semantics of backtracking in the matcher, and lock in a particular implementation. I will clarify the documentation to say that you shouldn't use functions that aren't safe to call 0, 1, or more times, in various orders, inside `match' patterns. -- sam th [email protected] _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
