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comparison lib/ur/monad.ur @ 937:37dd42935dad

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Summary row with aggregates
author Adam Chlipala <adamc@hcoop.net>
date Tue, 15 Sep 2009 10:18:56 -0400
parents 321a2d6feb40
children 8d3aa6c7cee0
comparison
equal deleted inserted replaced
936:6966d98c80b5 937:37dd42935dad
57 (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] (v : tf t) 57 (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] (v : tf t)
58 (acc : $(map tr rest)) => 58 (acc : $(map tr rest)) =>
59 v' <- f [nm] [t] v; 59 v' <- f [nm] [t] v;
60 return (acc ++ {nm = v'})) 60 return (acc ++ {nm = v'}))
61 {} 61 {}
62
63 fun mapR2 [K] [m] (_ : monad m) [tf1 :: K -> Type] [tf2 :: K -> Type] [tr :: K -> Type]
64 (f : nm :: Name -> t :: K -> tf1 t -> tf2 t -> m (tr t)) =
65 @@foldR2 [m] _ [tf1] [tf2] [fn r => $(map tr r)]
66 (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] (v1 : tf1 t) (v2 : tf2 t)
67 (acc : $(map tr rest)) =>
68 v' <- f [nm] [t] v1 v2;
69 return (acc ++ {nm = v'}))
70 {}