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jashkenas--coffeescript/test/slicing_and_splicing.coffee
zdenko aef54aeaf7 [CS2] Fix #4631: Expansion that becomes rest parameter causes runtime error (#4634)
* expansion-rest bug fix

* tests; improved implicit call recognition with dots on the left in the `rewriter`

* whitespace cleanup

* more tests
2017-08-17 13:13:52 -07:00

167 lines
3.9 KiB
CoffeeScript

# Slicing and Splicing
# --------------------
# * Slicing
# * Splicing
# shared array
shared = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
# Slicing
test "basic slicing", ->
arrayEq [7, 8, 9] , shared[7..9]
arrayEq [2, 3] , shared[2...4]
arrayEq [2, 3, 4, 5], shared[2...6]
test "slicing with variables as endpoints", ->
[a, b] = [1, 4]
arrayEq [1, 2, 3, 4], shared[a..b]
arrayEq [1, 2, 3] , shared[a...b]
test "slicing with expressions as endpoints", ->
[a, b] = [1, 3]
arrayEq [2, 3, 4, 5, 6], shared[(a+1)..2*b]
arrayEq [2, 3, 4, 5] , shared[a+1...(2*b)]
test "unbounded slicing", ->
arrayEq [7, 8, 9] , shared[7..]
arrayEq [8, 9] , shared[-2..]
arrayEq [9] , shared[-1...]
arrayEq [0, 1, 2] , shared[...3]
arrayEq [0, 1, 2, 3], shared[..-7]
arrayEq shared , shared[..-1]
arrayEq shared[0..8], shared[...-1]
for a in [-shared.length..shared.length]
arrayEq shared[a..] , shared[a...]
for a in [-shared.length+1...shared.length]
arrayEq shared[..a][...-1] , shared[...a]
arrayEq [1, 2, 3], [1, 2, 3][..]
test "#930, #835, #831, #746 #624: inclusive slices to -1 should slice to end", ->
arrayEq shared, shared[0..-1]
arrayEq shared, shared[..-1]
arrayEq shared.slice(1,shared.length), shared[1..-1]
test "string slicing", ->
str = "abcdefghijklmnopqrstuvwxyz"
ok str[1...1] is ""
ok str[1..1] is "b"
ok str[1...5] is "bcde"
ok str[0..4] is "abcde"
ok str[-5..] is "vwxyz"
test "#1722: operator precedence in unbounded slice compilation", ->
list = [0..9]
n = 2 # some truthy number in `list`
arrayEq [0..n], list[..n]
arrayEq [0..n], list[..n or 0]
arrayEq [0..n], list[..if n then n else 0]
test "#2349: inclusive slicing to numeric strings", ->
arrayEq [0, 1], [0..10][.."1"]
test "#4631: slicing with space before and/or after the dots", ->
a = (s) -> s
b = [4, 5, 6]
c = [7, 8, 9]
arrayEq [2, 3, 4], shared[2 ... 5]
arrayEq [3, 4, 5], shared[3... 6]
arrayEq [4, 5, 6], shared[4 ...7]
arrayEq shared[(a b...)...(a c...)] , shared[(a ...b)...(a ...c)]
arrayEq shared[(a b...) ... (a c...)], shared[(a ...b) ... (a ...c)]
arrayEq shared[(a b...)... (a c...)] , shared[(a ...b)... (a ...c)]
arrayEq shared[(a b...) ...(a c...)] , shared[(a ...b) ...(a ...c)]
# Splicing
test "basic splicing", ->
ary = [0..9]
ary[5..9] = [0, 0, 0]
arrayEq [0, 1, 2, 3, 4, 0, 0, 0], ary
ary = [0..9]
ary[2...8] = []
arrayEq [0, 1, 8, 9], ary
test "unbounded splicing", ->
ary = [0..9]
ary[3..] = [9, 8, 7]
arrayEq [0, 1, 2, 9, 8, 7]. ary
ary[...3] = [7, 8, 9]
arrayEq [7, 8, 9, 9, 8, 7], ary
ary[..] = [1, 2, 3]
arrayEq [1, 2, 3], ary
test "splicing with variables as endpoints", ->
[a, b] = [1, 8]
ary = [0..9]
ary[a..b] = [2, 3]
arrayEq [0, 2, 3, 9], ary
ary = [0..9]
ary[a...b] = [5]
arrayEq [0, 5, 8, 9], ary
test "splicing with expressions as endpoints", ->
[a, b] = [1, 3]
ary = [0..9]
ary[ a+1 .. 2*b+1 ] = [4]
arrayEq [0, 1, 4, 8, 9], ary
ary = [0..9]
ary[a+1...2*b+1] = [4]
arrayEq [0, 1, 4, 7, 8, 9], ary
test "splicing to the end, against a one-time function", ->
ary = null
fn = ->
if ary
throw 'err'
else
ary = [1, 2, 3]
fn()[0..] = 1
arrayEq ary, [1]
test "the return value of a splice literal should be the RHS", ->
ary = [0, 0, 0]
eq (ary[0..1] = 2), 2
ary = [0, 0, 0]
eq (ary[0..] = 3), 3
arrayEq [ary[0..0] = 0], [0]
test "#1723: operator precedence in unbounded splice compilation", ->
n = 4 # some truthy number in `list`
list = [0..9]
list[..n] = n
arrayEq [n..9], list
list = [0..9]
list[..n or 0] = n
arrayEq [n..9], list
list = [0..9]
list[..if n then n else 0] = n
arrayEq [n..9], list
test "#2953: methods on endpoints in assignment from array splice literal", ->
list = [0..9]
Number.prototype.same = -> this
list[1.same()...9.same()] = 5
delete Number.prototype.same
arrayEq [0, 5, 9], list