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comparison lib/ur/list.ur @ 1539:dde3bd82cb3d

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List.mapXi
author Adam Chlipala <adam@chlipala.net>
date Mon, 15 Aug 2011 10:22:09 -0400
parents ada582d07ae1
children 553a5cc3a4b5
comparison
equal deleted inserted replaced
1538:ade93cd5bc59 1539:dde3bd82cb3d
131 | x :: ls => <xml>{f x}{mapX' ls}</xml> 131 | x :: ls => <xml>{f x}{mapX' ls}</xml>
132 in 132 in
133 mapX' 133 mapX'
134 end 134 end
135 135
136 fun mapXi [a] [ctx ::: {Unit}] f =
137 let
138 fun mapX' i ls =
139 case ls of
140 [] => <xml/>
141 | x :: ls => <xml>{f i x}{mapX' (i + 1) ls}</xml>
142 in
143 mapX' 0
144 end
145
136 fun mapM [m ::: (Type -> Type)] (_ : monad m) [a] [b] f = 146 fun mapM [m ::: (Type -> Type)] (_ : monad m) [a] [b] f =
137 let 147 let
138 fun mapM' acc ls = 148 fun mapM' acc ls =
139 case ls of 149 case ls of
140 [] => return (rev acc) 150 [] => return (rev acc)