function_invocation.coffee

# Function Invocation
# -------------------

# * Function Invocation
# * Splats in Function Invocations
# * Implicit Returns
# * Explicit Returns

# shared identity function
id = (_) -> if arguments.length is 1 then _ else [arguments...]


test "basic argument passing", ->

  a = {}
  b = {}
  c = {}
  eq 1, (id 1)
  eq 2, (id 1, 2)[1]
  eq a, (id a)
  eq c, (id a, b, c)[2]


test "passing arguments on separate lines", ->

  a = {}
  b = {}
  c = {}
  ok(id(
    a
    b
    c
  )[1] is b)
  eq(0, id(
    0
    10
  )[0])
  eq(a,id(
    a
  ))
  eq b,
  (id b)


test "optional parens can be used in a nested fashion", ->

  call = (func) -> func()
  add = (a,b) -> a + b
  result = call ->
    inner = call ->
      add 5, 5
  ok result is 10


test "hanging commas and semicolons in argument list", ->

  fn = () -> arguments.length
  eq 2, fn(0,1,)
  eq 3, fn 0, 1,
  2
  eq 2, fn(0, 1;)
  # TODO: this test fails (the string compiles), but should it?
  #throws -> CoffeeScript.compile "fn(0,1,;)"
  throws -> CoffeeScript.compile "fn(0,1,;;)"
  throws -> CoffeeScript.compile "fn(0, 1;,)"
  throws -> CoffeeScript.compile "fn(,0)"
  throws -> CoffeeScript.compile "fn(;0)"


test "function invocation", ->

  func = ->
    return if true
  eq undefined, func()

  result = ("hello".slice) 3
  ok result is 'lo'


test "And even with strange things like this:", ->

  funcs  = [((x) -> x), ((x) -> x * x)]
  result = funcs[1] 5
  ok result is 25


test "More fun with optional parens.", ->

  fn = (arg) -> arg
  ok fn(fn {prop: 101}).prop is 101

  okFunc = (f) -> ok(f())
  okFunc -> true


test "chained function calls", ->
  nonce = {}
  identityWrap = (x) ->
    -> x
  eq nonce, identityWrap(identityWrap(nonce))()()
  eq nonce, (identityWrap identityWrap nonce)()()


test "Multi-blocks with optional parens.", ->

  fn = (arg) -> arg
  result = fn( ->
    fn ->
      "Wrapped"
  )
  ok result()() is 'Wrapped'


test "method calls", ->

  fnId = (fn) -> -> fn.apply this, arguments
  math = {
    add: (a, b) -> a + b
    anonymousAdd: (a, b) -> a + b
    fastAdd: fnId (a, b) -> a + b
  }
  ok math.add(5, 5) is 10
  ok math.anonymousAdd(10, 10) is 20
  ok math.fastAdd(20, 20) is 40


test "Ensure that functions can have a trailing comma in their argument list", ->

  mult = (x, mids..., y) ->
    x *= n for n in mids
    x *= y
  #ok mult(1, 2,) is 2
  #ok mult(1, 2, 3,) is 6
  ok mult(10, (i for i in [1..6])...) is 7200


test "`@` and `this` should both be able to invoke a method", ->
  nonce = {}
  fn          = (arg) -> eq nonce, arg
  fn.withAt   = -> @ nonce
  fn.withThis = -> this nonce
  fn.withAt()
  fn.withThis()


test "Trying an implicit object call with a trailing function.", ->

  a = null
  meth = (arg, obj, func) -> a = [obj.a, arg, func()].join ' '
  meth 'apple', b: 1, a: 13, ->
    'orange'
  ok a is '13 apple orange'


test "Ensure that empty functions don't return mistaken values.", ->

  obj =
    func: (@param, @rest...) ->
  ok obj.func(101, 102, 103, 104) is undefined
  ok obj.param is 101
  ok obj.rest.join(' ') is '102 103 104'


test "Passing multiple functions without paren-wrapping is legal, and should compile.", ->

  sum = (one, two) -> one() + two()
  result = sum ->
    7 + 9
  , ->
    1 + 3
  ok result is 20


test "Implicit call with a trailing if statement as a param.", ->

  func = -> arguments[1]
  result = func 'one', if false then 100 else 13
  ok result is 13


test "Test more function passing:", ->

  sum = (one, two) -> one() + two()

  result = sum( ->
    1 + 2
  , ->
    2 + 1
  )
  ok result is 6

  sum = (a, b) -> a + b
  result = sum(1
  , 2)
  ok result is 3


test "Chained blocks, with proper indentation levels:", ->

  counter =
    results: []
    tick: (func) ->
      @results.push func()
      this
  counter
    .tick ->
      3
    .tick ->
      2
    .tick ->
      1
  arrayEq [3,2,1], counter.results


test "This is a crazy one.", ->

  x = (obj, func) -> func obj
  ident = (x) -> x
  result = x {one: ident 1}, (obj) ->
    inner = ident(obj)
    ident inner
  ok result.one is 1


test "More paren compilation tests:", ->

  reverse = (obj) -> obj.reverse()
  ok reverse([1, 2].concat 3).join(' ') is '3 2 1'


test "Test for inline functions with parentheses and implicit calls.", ->

  combine = (func, num) -> func() * num
  result  = combine (-> 1 + 2), 3
  ok result is 9


test "Test for calls/parens/multiline-chains.", ->

  f = (x) -> x
  result = (f 1).toString()
    .length
  ok result is 1


test "Test implicit calls in functions in parens:", ->

  result = ((val) ->
    [].push val
    val
  )(10)
  ok result is 10


test "Ensure that chained calls with indented implicit object literals below are alright.", ->

  result = null
  obj =
    method: (val)  -> this
    second: (hash) -> result = hash.three
  obj
    .method(
      101
    ).second(
      one:
        two: 2
      three: 3
    )
  eq result, 3


test "Test newline-supressed call chains with nested functions.", ->

  obj  =
    call: -> this
  func = ->
    obj
      .call ->
        one two
      .call ->
        three four
    101
  eq func(), 101


test "Implicit objects with number arguments.", ->

  func = (x, y) -> y
  obj =
    prop: func "a", 1
  ok obj.prop is 1


test "Non-spaced unary and binary operators should cause a function call.", ->

  func = (val) -> val + 1
  ok (func +5) is 6
  ok (func -5) is -4


test "Prefix unary assignment operators are allowed in parenless calls.", ->

  func = (val) -> val + 1
  val = 5
  ok (func --val) is 5

test "#855: execution context for `func arr...` should be `null`", ->
  contextTest = -> eq @, if window? then window else global
  array = []
  contextTest array
  contextTest.apply null, array
  contextTest array...

test "#904: Destructuring function arguments with same-named variables in scope", ->
  a = b = nonce = {}
  fn = ([a,b]) -> {a:a,b:b}
  result = fn([c={},d={}])
  eq c, result.a
  eq d, result.b
  eq nonce, a
  eq nonce, b

test "Simple Destructuring function arguments with same-named variables in scope", ->
  x = 1
  f = ([x]) -> x
  eq f([2]), 2
  eq x, 1

test "caching base value", ->

  obj =
    index: 0
    0: {method: -> this is obj[0]}
  ok obj[obj.index++].method([]...)


test "passing splats to functions", ->
  arrayEq [0..4], id id [0..4]...
  fn = (a, b, c..., d) -> [a, b, c, d]
  range = [0..3]
  [first, second, others, last] = fn range..., 4, [5...8]...
  eq 0, first
  eq 1, second
  arrayEq [2..6], others
  eq 7, last

test "splat variables are local to the function", ->
  outer = "x"
  clobber = (avar, outer...) -> outer
  clobber "foo", "bar"
  eq "x", outer


test "Issue 894: Splatting against constructor-chained functions.", ->

  x = null
  class Foo
    bar: (y) -> x = y
  new Foo().bar([101]...)
  eq x, 101


test "Functions with splats being called with too few arguments.", ->

  pen = null
  method = (first, variable..., penultimate, ultimate) ->
    pen = penultimate
  method 1, 2, 3, 4, 5, 6, 7, 8, 9
  ok pen is 8
  method 1, 2, 3
  ok pen is 2
  method 1, 2
  ok pen is 2


test "splats with super() within classes.", ->

  class Parent
    meth: (args...) ->
      args
  class Child extends Parent
    meth: ->
      nums = [3, 2, 1]
      super nums...
  ok (new Child).meth().join(' ') is '3 2 1'


test "#1011: passing a splat to a method of a number", ->
  eq '1011', 11.toString [2]...
  eq '1011', (31).toString [3]...
  eq '1011', 69.0.toString [4]...
  eq '1011', (131.0).toString [5]...


test "splats and the `new` operator: functions that return `null` should construct their instance", ->
  args = []
  child = new (constructor = -> null) args...
  ok child instanceof constructor

test "splats and the `new` operator: functions that return functions should construct their return value", ->
  args = []
  fn = ->
  child = new (constructor = -> fn) args...
  ok child not instanceof constructor
  eq fn, child

test "implicit return", ->

  eq ok, new ->
    ok
    ### Should `return` implicitly   ###
    ### even with trailing comments. ###


test "implicit returns with multiple branches", ->
  nonce = {}
  fn = ->
    if false
      for a in b
        return c if d
    else
      nonce
  eq nonce, fn()


test "implicit returns with switches", ->
  nonce = {}
  fn = ->
    switch nonce
      when nonce then nonce
      else return undefined
  eq nonce, fn()


test "preserve context when generating closure wrappers for expression conversions", ->
  nonce = {}
  obj =
    property: nonce
    method: ->
      this.result = if false
        10
      else
        "a"
        "b"
        this.property
  eq nonce, obj.method()
  eq nonce, obj.property


test "don't wrap 'pure' statements in a closure", ->
  nonce = {}
  items = [0, 1, 2, 3, nonce, 4, 5]
  fn = (items) ->
    for item in items
      return item if item is nonce
  eq nonce, fn items


test "usage of `new` is careful about where the invocation parens end up", ->
  eq 'object', typeof new try Array
  eq 'object', typeof new do -> ->


test "implicit call against control structures", ->
  result = null
  save   = (obj) -> result = obj

  save switch id false
    when true
      'true'
    when false
      'false'

  eq result, 'false'

  save if id false
    'false'
  else
    'true'

  eq result, 'true'

  save unless id false
    'true'
  else
    'false'

  eq result, 'true'

  save try
    doesnt exist
  catch error
    'caught'

  eq result, 'caught'

  save try doesnt(exist) catch error then 'caught2'

  eq result, 'caught2'


test "#1420: things like `(fn() ->)`; there are no words for this one", ->
  fn = -> (f) -> f()
  nonce = {}
  eq nonce, (fn() -> nonce)

test "#1416: don't omit one 'new' when compiling 'new new'", ->
  nonce = {}
  obj = new new -> -> {prop: nonce}
  eq obj.prop, nonce

test "#1416: don't omit one 'new' when compiling 'new new fn()()'", ->
  nonce = {}
  argNonceA = {}
  argNonceB = {}
  fn = (a) -> (b) -> {a, b, prop: nonce}
  obj = new new fn(argNonceA)(argNonceB)
  eq obj.prop, nonce
  eq obj.a, argNonceA
  eq obj.b, argNonceB

test "#1840: accessing the `prototype` after function invocation should compile", ->
  doesNotThrow -> CoffeeScript.compile 'fn()::prop'

  nonce = {}
  class Test then id: nonce

  dotAccess = -> Test::
  protoAccess = -> Test

  eq dotAccess().id, nonce
  eq protoAccess()::id, nonce

test "#960: improved 'do'", ->

  do (nonExistent = 'one') ->
    eq nonExistent, 'one'

  overridden = 1
  do (overridden = 2) ->
    eq overridden, 2

  two = 2
  do (one = 1, two, three = 3) ->
    eq one, 1
    eq two, 2
    eq three, 3

  ret = do func = (two) ->
    eq two, 2
    func
  eq ret, func

test "#2617: implicit call before unrelated implicit object", ->
  pass = ->
    true

  result = if pass 1
    one: 1
  eq result.one, 1

test "#2292, b: f (z),(x)", ->
  f = (x, y) -> y
  one = 1
  two = 2
  o = b: f (one),(two)
  eq o.b, 2

test "#2297, Different behaviors on interpreting literal", ->
  foo = (x, y) -> y
  bar =
    baz: foo 100, on

  eq bar.baz, on

  qux = (x) -> x
  quux = qux
    corge: foo 100, true

  eq quux.corge, on

  xyzzy =
    e: 1
    f: foo
      a: 1
      b: 2
    ,
      one: 1
      two: 2
      three: 3
    g:
      a: 1
      b: 2
      c: foo 2,
        one: 1
        two: 2
        three: 3
      d: 3
    four: 4
    h: foo one: 1, two: 2, three: three: three: 3,
      2

  eq xyzzy.f.two, 2
  eq xyzzy.g.c.three, 3
  eq xyzzy.four, 4
  eq xyzzy.h, 2

test "#2715, Chained implicit calls", ->
  first  = (x)    -> x
  second = (x, y) -> y

  foo = first first
    one: 1
  eq foo.one, 1

  bar = first second
    one: 1, 2
  eq bar, 2

  baz = first second
    one: 1,
    2
  eq baz, 2

test "Implicit calls and new", ->
  first = (x) -> x
  foo = (@x) ->
  bar = first new foo first 1
  eq bar.x, 1

  third = (x, y, z) -> z
  baz = first new foo new foo third
        one: 1
        two: 2
        1
        three: 3
        2
  eq baz.x.x.three, 3

test "Loose tokens inside of explicit call lists", ->
  first = (x) -> x
  second = (x, y) -> y
  one = 1

  foo = second( one
                2)
  eq foo, 2

  bar = first( first
               one: 1)
  eq bar.one, 1