From: Jim Pryor Date: Fri, 19 Nov 2010 13:06:05 +0000 (-0500) Subject: assignment7 tweaks X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=commitdiff_plain;h=002bbc4734d89967f6941fcff5021b4d1c661f2b assignment7 tweaks Signed-off-by: Jim Pryor --- diff --git a/hints/assignment_7_hint_4.mdwn b/hints/assignment_7_hint_4.mdwn index e3b0346f..346d98b3 100644 --- a/hints/assignment_7_hint_4.mdwn +++ b/hints/assignment_7_hint_4.mdwn @@ -54,7 +54,9 @@ then empty_set else unit_set (bind dpm entity_dpm (fun e -> unit_dpm (Q e))) - Doing things this way will discard `bool dpm`s that start out wrapping `false`, and will pass through other `bool dpm`s that start out wrapping `true` but which our current filter transforms to a wrapped `false`. You might instead aim for consistency, and always pass through wrapped `false`s, whether they started out that way or are only now being generated; or instead always discard such, and only pass through wrapped `true`s. But what we have here will work fine too. + Applied to an entity_dpm, that yields a function that we can bind to a `bool dpm set` and that will transform the doubly-wrapped `bool` into a new `bool dpm set`. + + Doing things this way will discard `bool dpm`s from the set that started out wrapping `false`, and will pass through other `bool dpm`s that start out wrapping `true` but which our current filter transforms to a wrapped `false`. You might instead aim for consistency, and always pass through wrapped `false`s, whether they started out that way or are only now being generated; or instead always discard such, and only pass through wrapped `true`s. But what we have here will work fine too. If we let that be \[[Q]], then \[[Q]] \[[x]] would be: