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# Comprehensions
# --------------
# * Array Comprehensions
# * Range Comprehensions
# * Object Comprehensions
# * Implicit Destructuring Assignment
# * Comprehensions with Nonstandard Step
# TODO: refactor comprehension tests
test "Basic array comprehensions.", ->
nums = (n * n for n in [1, 2, 3] when n & 1)
results = (n * 2 for n in nums)
ok results.join(',') is '2,18'
test "Basic object comprehensions.", ->
obj = {one: 1, two: 2, three: 3}
names = (prop + '!' for prop of obj)
odds = (prop + '!' for prop, value of obj when value & 1)
ok names.join(' ') is "one! two! three!"
ok odds.join(' ') is "one! three!"
test "Basic range comprehensions.", ->
nums = (i * 3 for i in [1..3])
negs = (x for x in [-20..-5*2])
negs = negs[0..2]
result = nums.concat(negs).join(', ')
ok result is '3, 6, 9, -20, -19, -18'
test "With range comprehensions, you can loop in steps.", ->
results = (x for x in [0...15] by 5)
ok results.join(' ') is '0 5 10'
results = (x for x in [0..100] by 10)
ok results.join(' ') is '0 10 20 30 40 50 60 70 80 90 100'
test "And can loop downwards, with a negative step.", ->
results = (x for x in [5..1])
ok results.join(' ') is '5 4 3 2 1'
ok results.join(' ') is [(10-5)..(-2+3)].join(' ')
results = (x for x in [10..1])
ok results.join(' ') is [10..1].join(' ')
results = (x for x in [10...0] by -2)
ok results.join(' ') is [10, 8, 6, 4, 2].join(' ')
test "Range comprehension gymnastics.", ->
eq "#{i for i in [5..1]}", '5,4,3,2,1'
eq "#{i for i in [5..-5] by -5}", '5,0,-5'
a = 6
b = 0
c = -2
eq "#{i for i in [a..b]}", '6,5,4,3,2,1,0'
eq "#{i for i in [a..b] by c}", '6,4,2,0'
test "Multiline array comprehension with filter.", ->
evens = for num in [1, 2, 3, 4, 5, 6] when not (num & 1)
num *= -1
num -= 2
num * -1
eq evens + '', '4,6,8'
test "The in operator still works, standalone.", ->
ok 2 of evens
test "all isn't reserved.", ->
all = 1
test "Ensure that the closure wrapper preserves local variables.", ->
obj = {}
for method in ['one', 'two', 'three'] then do (method) ->
obj[method] = ->
"I'm " + method
ok obj.one() is "I'm one"
ok obj.two() is "I'm two"
ok obj.three() is "I'm three"
test "Index values at the end of a loop.", ->
i = 0
for i in [1..3]
-> 'func'
break if false
ok i is 4
test "Ensure that local variables are closed over for range comprehensions.", ->
funcs = for i in [1..3]
do (i) ->
-> -i
eq (func() for func in funcs).join(' '), '-1 -2 -3'
ok i is 4
test "Even when referenced in the filter.", ->
list = ['one', 'two', 'three']
methods = for num, i in list when num isnt 'two' and i isnt 1
do (num, i) ->
-> num + ' ' + i
ok methods.length is 2
ok methods[0]() is 'one 0'
ok methods[1]() is 'three 2'
test "Even a convoluted one.", ->
funcs = []
for i in [1..3]
do (i) ->
x = i * 2
((z)->
funcs.push -> z + ' ' + i
)(x)
ok (func() for func in funcs).join(', ') is '2 1, 4 2, 6 3'
funcs = []
results = for i in [1..3]
do (i) ->
z = (x * 3 for x in [1..i])
((a, b, c) -> [a, b, c].join(' ')).apply this, z
ok results.join(', ') is '3 , 3 6 , 3 6 9'
test "Naked ranges are expanded into arrays.", ->
array = [0..10]
ok(num % 2 is 0 for num in array by 2)
test "Nested shared scopes.", ->
foo = ->
for i in [0..7]
do (i) ->
for j in [0..7]
do (j) ->
-> i + j
eq foo()[3][4](), 7
test "Scoped loop pattern matching.", ->
a = [[0], [1]]
funcs = []
for [v] in a
do (v) ->
funcs.push -> v
eq funcs[0](), 0
eq funcs[1](), 1
test "Nested comprehensions.", ->
multiLiner =
for x in [3..5]
for y in [3..5]
[x, y]
singleLiner =
(([x, y] for y in [3..5]) for x in [3..5])
ok multiLiner.length is singleLiner.length
ok 5 is multiLiner[2][2][1]
ok 5 is singleLiner[2][2][1]
test "Comprehensions within parentheses.", ->
result = null
store = (obj) -> result = obj
store (x * 2 for x in [3, 2, 1])
ok result.join(' ') is '6 4 2'
test "Closure-wrapped comprehensions that refer to the 'arguments' object.", ->
expr = ->
result = (item * item for item in arguments)
ok expr(2, 4, 8).join(' ') is '4 16 64'
test "Fast object comprehensions over all properties, including prototypal ones.", ->
class Cat
constructor: -> @name = 'Whiskers'
breed: 'tabby'
hair: 'cream'
whiskers = new Cat
own = (value for own key, value of whiskers)
all = (value for key, value of whiskers)
ok own.join(' ') is 'Whiskers'
ok all.sort().join(' ') is 'Whiskers cream tabby'
test "Optimized range comprehensions.", ->
exxes = ('x' for [0...10])
ok exxes.join(' ') is 'x x x x x x x x x x'
test "Comprehensions safely redeclare parameters if they're not present in closest scope.", ->
rule = (x) -> x
learn = ->
rule for rule in [1, 2, 3]
ok learn().join(' ') is '1 2 3'
ok rule(101) is 101
f = -> [-> ok no, 'should cache source']
ok yes for k of [f] = f()
test "Lenient on pure statements not trying to reach out of the closure", ->
val = for i in [1]
for j in [] then break
i
ok val[0] is i
test "Comprehensions only wrap their last line in a closure, allowing other lines
to have pure expressions in them.", ->
func = -> for i in [1]
break if i is 2
j for j in [1]
ok func()[0][0] is 1
i = 6
odds = while i--
continue unless i & 1
i
ok odds.join(', ') is '5, 3, 1'
test "Issue #897: Ensure that plucked function variables aren't leaked.", ->
facets = {}
list = ['one', 'two']
(->
for entity in list
facets[entity] = -> entity
)()
eq typeof entity, 'undefined'
eq facets['two'](), 'two'
test "Issue #905. Soaks as the for loop subject.", ->
a = {b: {c: [1, 2, 3]}}
for d in a.b?.c
e = d
eq e, 3
test "Issue #948. Capturing loop variables.", ->
funcs = []
list = ->
[1, 2, 3]
for y in list()
do (y) ->
z = y
funcs.push -> "y is #{y} and z is #{z}"
eq funcs[1](), "y is 2 and z is 2"
test "Cancel the comprehension if there's a jump inside the loop.", ->
result = try
for i in [0...10]
continue if i < 5
i
eq result, 10
test "Comprehensions over break.", ->
arrayEq (break for [1..10]), []
test "Comprehensions over continue.", ->
arrayEq (continue for [1..10]), []
test "Comprehensions over function literals.", ->
a = 0
for f in [-> a = 1]
do (f) ->
do f
eq a, 1
test "Comprehensions that mention arguments.", ->
list = [arguments: 10]
args = for f in list
do (f) ->
f.arguments
eq args[0], 10
test "expression conversion under explicit returns", ->
nonce = {}
fn = ->
return (nonce for x in [1,2,3])
arrayEq [nonce,nonce,nonce], fn()
fn = ->
return [nonce for x in [1,2,3]][0]
arrayEq [nonce,nonce,nonce], fn()
fn = ->
return [(nonce for x in [1..3])][0]
arrayEq [nonce,nonce,nonce], fn()
test "implicit destructuring assignment in object of objects", ->
a={}; b={}; c={}
obj = {
a: { d: a },
b: { d: b }
c: { d: c }
}
result = ([y,z] for y, { d: z } of obj)
arrayEq [['a',a],['b',b],['c',c]], result
test "implicit destructuring assignment in array of objects", ->
a={}; b={}; c={}; d={}; e={}; f={}
arr = [
{ a: a, b: { c: b } },
{ a: c, b: { c: d } },
{ a: e, b: { c: f } }
]
result = ([y,z] for { a: y, b: { c: z } } in arr)
arrayEq [[a,b],[c,d],[e,f]], result
test "implicit destructuring assignment in array of arrays", ->
a={}; b={}; c={}; d={}; e={}; f={}
arr = [[a, [b]], [c, [d]], [e, [f]]]
result = ([y,z] for [y, [z]] in arr)
arrayEq [[a,b],[c,d],[e,f]], result
test "issue #1124: don't assign a variable in two scopes", ->
lista = [1, 2, 3, 4, 5]
listb = (_i + 1 for _i in lista)
arrayEq [2, 3, 4, 5, 6], listb
test "#1326: `by` value is uncached", ->
a = [0,1,2]
fi = gi = hi = 0
f = -> ++fi
g = -> ++gi
h = -> ++hi
forCompile = []
rangeCompileSimple = []
#exercises For.compile
for v,i in a by f() then forCompile.push i
#exercises Range.compileSimple
rangeCompileSimple = (i for i in [0..2] by g())
arrayEq a, forCompile
arrayEq a, rangeCompileSimple
#exercises Range.compile
eq "#{i for i in [0..2] by h()}", '0,1,2'
test "#1669: break/continue should skip the result only for that branch", ->
ns = for n in [0..99]
if n > 9
break
else if n & 1
continue
else
n
eq "#{ns}", '0,2,4,6,8'
# `else undefined` is implied.
ns = for n in [1..9]
if n % 2
continue unless n % 5
n
eq "#{ns}", "1,,3,,,7,,9"
# Ditto.
ns = for n in [1..9]
switch
when n % 2
continue unless n % 5
n
eq "#{ns}", "1,,3,,,7,,9"
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