de6053b · elk · git.iko.soy

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Augment the List library

de6053bEvan Czaplicki12 years ago

changelog.md+7

compare with master

unifiedsplit

@@ -6,6 +6,8 @@

6 * Type aliases in port types

7 * Add Keyboard.alt and Keyboard.meta

8 * Add Debug.crash

9+ * Add List.indexedMap and List.filterMap

10+ * Add Maybe.map

9 * Add --bundle-runtime flag which creates stand-alone Elm programs

11 * Add --bundle-runtime flag which creates stand-alone Elm programs

10 * Error on ambiguious use of imported variables

12 * Error on ambiguious use of imported variables

11 * Better architecture for compiler. Uses types to make compilation pipeline

13 * Better architecture for compiler. Uses types to make compilation pipeline

@@ -14,6 +16,11 @@

15#### Breaking Changes:

17#### Breaking Changes:

19+ * Rename Maybe.maybe to Maybe.extract

20+ * Rename Either.either to Either.extract

21+ * Remove Maybe.justs for (List.filterMap id)

22+ * Remove List.and for (List.foldl (&&) True)

23+ * Remove List.or for (List.foldl (||) False)

17 * Unambiguous syntax for importing ADTs and type aliases (whoo!)

24 * Unambiguous syntax for importing ADTs and type aliases (whoo!)

18 * sqrt and logBase both only work on Floats now

25 * sqrt and logBase both only work on Floats now

libraries/List.elm+32−11

@@ -10,16 +10,19 @@ list must have the same type.

10@docs head, tail, last, filter, take, drop

12# Putting Lists Together

13−@docs concat, concatMap, join, intersperse, zip, zipWith, repeat

13+@docs concat, join, intersperse, zip, zipWith, repeat

15# Taking Lists Apart

16@docs partition, unzip

18# Folds

19−@docs foldr, foldl, foldr1, foldl1, scanl, scanl1

19+@docs foldr, foldl

20+

21+# Special Maps

22+@docs filterMap, concatMap, indexedMap

21# Special Folds

24# Special Folds

22−@docs sum, product, maximum, minimum, all, any, and, or

25+@docs sum, product, maximum, minimum, all, any, foldr1, foldl1, scanl, scanl1

24# Sorting

27# Sorting

25@docs sort, sortBy, sortWith

28@docs sort, sortBy, sortWith

@@ -35,6 +38,7 @@ possibly should be approached another way.

35-}

38-}

37import Basics (..)

40import Basics (..)

41+import Maybe ( Maybe(Just,Nothing) )

38import Native.List

42import Native.List

40{-| Add an element to the front of a list `(1 :: [2,3] == [1,2,3])` -}

44{-| Add an element to the front of a list `(1 :: [2,3] == [1,2,3])` -}

@@ -81,6 +85,15 @@ isEmpty xs =

81map : (a -> b) -> [a] -> [b]

85map : (a -> b) -> [a] -> [b]

82map = Native.List.map

86map = Native.List.map

88+{-| Same as `map` but the function is also applied to the index of each

89+element (starting at zero).

90+

91+ indexedMap (,) ["Tom","Sue","Bob"] == [ (0,"Tom"), (1,"Sue"), (2,"Bob") ]

92+-}

93+indexedMap : (Int -> a -> b) -> [a] -> [b]

94+indexedMap f xs =

95+ zipWith f [ 0 .. length xs - 1 ] xs

96+

84{-| Reduce a list from the left: `(foldl (::) [] [1,2,3] == [3,2,1])` -}

97{-| Reduce a list from the left: `(foldl (::) [] [1,2,3] == [3,2,1])` -}

85foldl : (a -> b -> b) -> b -> [a] -> b

98foldl : (a -> b -> b) -> b -> [a] -> b

86foldl = Native.List.foldl

99foldl = Native.List.foldl

@@ -117,6 +130,22 @@ scanl1 = Native.List.scanl1

117filter : (a -> Bool) -> [a] -> [a]

130filter : (a -> Bool) -> [a] -> [a]

118filter = Native.List.filter

131filter = Native.List.filter

119

132

133+{-| Apply a function that may succeed to all values in the list, but only keep

134+the successes.

135+

136+ toInt : String -> Maybe Int

137+

138+ filterMap toInt ["3", "4.0", "5", "hats"] == [3,5]

139+-}

140+filterMap : (a -> Maybe b) -> [a] -> [b]

141+filterMap xs = Native.List.foldr maybeCons [] xs

142+

143+maybeCons : Maybe a -> [a] -> [a]

144+maybeCons mx xs =

145+ case mx of

146+ Just x -> x :: xs

147+ Nothing -> xs

148+

120{-| Determine the length of a list: `(length [1,2,3] == 3)` -}

149{-| Determine the length of a list: `(length [1,2,3] == 3)` -}

121length : [a] -> Int

150length : [a] -> Int

122length = Native.List.length

151length = Native.List.length

@@ -133,14 +162,6 @@ all = Native.List.all

133any : (a -> Bool) -> [a] -> Bool

162any : (a -> Bool) -> [a] -> Bool

134any = Native.List.any

163any = Native.List.any

135

164

136−{-| Check to see if all elements are True. -}

137−and : [Bool] -> Bool

138−and = foldl (&&) True

139−

140−{-| Check to see if any elements are True. -}

141−or : [Bool] -> Bool

142−or = foldl (||) False

143−

144{-| Concatenate a list of appendable things:

165{-| Concatenate a list of appendable things:

145

166

146 concat [[1,2],[3],[4,5]] == [1,2,3,4,5]

167 concat [[1,2],[3],[4,5]] == [1,2,3,4,5]

libraries/Maybe.elm+1−14

@@ -1,4 +1,4 @@

1−module Maybe (Maybe(..), maybe, isJust, isNothing, justs) where

1+module Maybe (Maybe(..), maybe, isJust, isNothing) where

3{-| Represents an optional value. Maybe it is there, maybe it is not.

@@ -8,12 +8,9 @@ module Maybe (Maybe(..), maybe, isJust, isNothing, justs) where

8# Taking Maybes apart

9@docs maybe, isJust, isNothing

11−# Maybes and Lists

12−@docs justs

13-}

11-}

15import Basics (not, (.))

13import Basics (not, (.))

16−import List (foldr, (::))

18{-| The Maybe datatype. Useful when a computation may or may not

15{-| The Maybe datatype. Useful when a computation may or may not

19result in a value (e.g. logarithm is defined only for positive

16result in a value (e.g. logarithm is defined only for positive

@@ -53,13 +50,3 @@ isJust = maybe False (\_ -> True)

53-}

50-}

54isNothing : Maybe a -> Bool

51isNothing : Maybe a -> Bool

55isNothing = not . isJust

52isNothing = not . isJust

56−

57−cons : Maybe a -> [a] -> [a]

58−cons mx xs = maybe xs (\x -> x :: xs) mx

59−

60−{-| Filters out Nothings and extracts the remaining values.

61−

62− justs [Just 0, Nothing, Just 5, Just 7] == [0,5,7]

63−-}

64−justs : [Maybe a] -> [a]

65−justs = foldr cons []