513ce27 · elk · git.iko.soy

libraries/Array.elm+15−7

compare with master

unifiedsplit

@@ -14,7 +14,7 @@ reads, updates, and appends.

14@docs get, getOrElse, getOrFail, set

15

16# Taking Arrays Apart

17−@docs toList, toIndexedList, slice

17+@docs slice, toList, toIndexedList

18

19# Mapping and Folding

20@docs map, indexedMap, foldl, foldr

@@ -163,13 +163,21 @@ If the index is out of range, the array is unaltered.

163set : Int -> a -> Array a -> Array a

164set = Native.Array.set

165

166−{-| Slice an array given a range. The selection is inclusive, so the last

166+{-| Get a sub-section of an array: `(slice start end array)`. The `start` is a

167−element in the selection will also be in the new array. This may change in the

167+zero-based index where we will start our slice. The `end` is a zero-based index

168−future. You can select from the end by giving a negative Int.

168+that indicates the end of the slice. The slice extracts up to but not including

169+`end`.

169

170

170− slice 1 2 (fromList [0,1,2,3,4]) == fromList [1,2]

171+ slice 0 3 (fromList [0,1,2,3,4]) == fromList [0,1,2]

171− slice 1 -2 (fromList [0,1,2,3,4]) == fromList [1,2,3]

172+ slice 1 4 (fromList [0,1,2,3,4]) == fromList [1,2,3]

173+

174+Both the `start` and `end` indexes can be negative, indicating an offset from

175+the end of the array.

176+

177+ slice 1 -1 (fromList [0,1,2,3,4]) == fromList [1,2,3]

172− slice -3 -2 (fromList [0,1,2,3,4]) == fromList [2,3]

178+ slice -2 5 (fromList [0,1,2,3,4]) == fromList [3,4]

179+

180+This makes it pretty easy to `pop` the last element off of an array: `slice 0 -1 array`

173-}

181-}

174slice : Int -> Int -> Array a -> Array a

182slice : Int -> Int -> Array a -> Array a

175slice = Native.Array.slice

183slice = Native.Array.slice

libraries/Native/Array.js+1−4

@@ -262,9 +262,6 @@ Elm.Native.Array.make = function(elm) {

262 return b;

263 }

264

265− // Returns a sliced tree. "to" is inclusive, but this may change,

266− // when I understand, why e.g. JS does not handle it this way. :-)

267− // If "from" or "to" is negative, they will select from the end on.

268 // TODO: currently, it slices the right, then the left. This can be

265 // TODO: currently, it slices the right, then the left. This can be

269 // optimized.

266 // optimized.

270 function slice(from, to, a) {

267 function slice(from, to, a) {

@@ -281,7 +278,7 @@ Elm.Native.Array.make = function(elm) {

281 // Handle leaf level.

278 // Handle leaf level.

282 if (a.height == 0) {

279 if (a.height == 0) {

283 var newA = { ctor:"_Array", height:0 };

280 var newA = { ctor:"_Array", height:0 };

284− newA.table = a.table.slice(0, to + 1);

281+ newA.table = a.table.slice(0, to);

285 return newA;

282 return newA;

286 }

283 }

287

284

tests/elm/Test/Array.elm+4−3

@@ -39,9 +39,10 @@ tests =

39 takingArraysApartTests = suite "Taking Arrays Apart"

40 [ test "toList" <| assertEqual [3,5,8] (Array.toList (Array.fromList [3,5,8]))

41 , test "toIndexedList" <| assertEqual [(0,"cat"), (1,"dog")] (Array.toIndexedList (Array.fromList ["cat","dog"]))

42− , test "slice 1" <| assertEqual (Array.fromList [1,2]) (Array.slice 1 2 (Array.fromList [0,1,2,3,4]))

42+ , test "slice 1" <| assertEqual (Array.fromList [0,1,2]) (Array.slice 0 3 (Array.fromList [0,1,2,3,4]))

43+ , test "slice 2" <| assertEqual (Array.fromList [1,2,3]) (Array.slice 1 4 (Array.fromList [0,1,2,3,4]))

43− , test "slice 2" <| assertEqual (Array.fromList [1,2,3]) (Array.slice 1 -2 (Array.fromList [0,1,2,3,4]))

44+ , test "slice 3" <| assertEqual (Array.fromList [1,2,3]) (Array.slice 1 -1 (Array.fromList [0,1,2,3,4]))

44− , test "slice 3" <| assertEqual (Array.fromList [2,3]) (Array.slice -3 -2 (Array.fromList [0,1,2,3,4]))

45+ , test "slice 4" <| assertEqual (Array.fromList [2]) (Array.slice -3 -2 (Array.fromList [0,1,2,3,4]))

45 ]

46 ]

46 mappingAndFoldingTests = suite "Mapping and Folding"

47 mappingAndFoldingTests = suite "Mapping and Folding"

47 [ test "map" <| assertEqual (Array.fromList [1,2,3]) (Array.map sqrt (Array.fromList [1,4,9]))

48 [ test "map" <| assertEqual (Array.fromList [1,2,3]) (Array.map sqrt (Array.fromList [1,4,9]))