X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?a=blobdiff_plain;f=topics%2Fweek7_introducing_monads.mdwn;h=adcf0cc2d42333ff35f1311dca7d215d2aa95cb9;hb=787297d94b859a55fc0ae9c2f9ff1fa301fb0460;hp=81ccafb2ccd3729ab970574b98cc3b6a8af8468a;hpb=a914ff0ed48112619a514100394a5f2a0fcbc132;p=lambda.git
diff --git a/topics/week7_introducing_monads.mdwn b/topics/week7_introducing_monads.mdwn
index 81ccafb2..adcf0cc2 100644
--- a/topics/week7_introducing_monads.mdwn
+++ b/topics/week7_introducing_monads.mdwn
@@ -111,7 +111,7 @@ Here are the types of our crucial functions, together with our pronunciation, an
>>= or mbind : (Q) -> (Q -> R) -> (R)
-=<< (flip mbind, should we call it mdnib?) (Q) -> (Q -> R) -> (R)
+=<< (flip mbind, should we call it mdnib?) (Q -> R) -> (Q) -> (R)
join: P -> P
@@ -127,7 +127,11 @@ certain useful guarantees.
if there is a `map` function defined for that box type with the type given above. This
has to obey the following Map Laws:
- TODO LAWS
+ map (id : α -> α) = (id : α -> α)
+ map (g â f) = (map g) â (map f)
+
+ Essentially these say that `map` is a homomorphism from `(α -> β, â, id)` to (α -> β, â', id')
, where `â'` and `id'` are `â` and `id` restricted to arguments of type _
.
+
* ***MapNable*** (in Haskelese, "Applicatives") A Mappable box type is *MapNable*
if there are in addition `map2`, `mid`, and `mapply`. (Given either