Mercurial > urweb
comparison lib/ur/list.ur @ 818:066493f7f008
Change List.mapM' to avoid leaving functions around
| author | Adam Chlipala <adamc@hcoop.net> |
|---|---|
| date | Thu, 21 May 2009 11:45:04 -0400 |
| parents | e92cfac1608f |
| children | 395a5d450cc0 |
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| 817:4585f744574a | 818:066493f7f008 |
|---|---|
| 42 | 42 |
| 43 fun mapM (m ::: (Type -> Type)) (_ : monad m) (a ::: Type) (b ::: Type) f = | 43 fun mapM (m ::: (Type -> Type)) (_ : monad m) (a ::: Type) (b ::: Type) f = |
| 44 let | 44 let |
| 45 fun mapM' acc ls = | 45 fun mapM' acc ls = |
| 46 case ls of | 46 case ls of |
| 47 [] => acc | 47 [] => return (rev acc) |
| 48 | x :: ls => mapM' (x' <- f x; ls' <- acc; return (x' :: ls')) ls | 48 | x :: ls => x' <- f x; mapM' (x' :: acc) ls |
| 49 in | 49 in |
| 50 mapM' (return []) | 50 mapM' [] |
| 51 end | 51 end |