Antonio Vieiro scripsit: > In the example above you want *sequential* evaluation (so as not to mess > up with random internals, if those are not synchronized, becasue random > that has an internal state), but you can evaluate operands in any order > because '+' is commutative.
I'm going to highlight this not because I think you mean it, but because it's an easy slip of the mind to make. The arguments to any function, whether commutative or associative or both or neither, can be evaluated in any order desired. Those properties matter only when the called procedure actually *processes* its arguments. Even if (- (a) (b)) calls b before a, the - procedure will still return the right answer. -- It was impossible to inveigle John Cowan <[email protected]> Georg Wilhelm Friedrich Hegel http://www.ccil.org/~cowan Into offering the slightest apology For his Phenomenology. --W. H. Auden, from "People" (1953) _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
