1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
require_relative '../spec_helper'
describe "Numbered parameters" do
it "provides default parameters _1, _2, ... in a block" do
-> { _1 }.call("a").should == "a"
proc { _1 }.call("a").should == "a"
lambda { _1 }.call("a").should == "a"
["a"].map { _1 }.should == ["a"]
end
it "assigns nil to not passed parameters" do
proc { [_1, _2] }.call("a").should == ["a", nil]
proc { [_1, _2] }.call("a", "b").should == ["a", "b"]
end
it "supports variables _1-_9 only for the first 9 passed parameters" do
block = proc { [_1, _2, _3, _4, _5, _6, _7, _8, _9] }
result = block.call(1, 2, 3, 4, 5, 6, 7, 8, 9)
result.should == [1, 2, 3, 4, 5, 6, 7, 8, 9]
end
it "does not support more than 9 parameters" do
-> {
proc { [_10] }.call(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
}.should raise_error(NameError, /undefined local variable or method `_10'/)
end
it "can not be used in both outer and nested blocks at the same time" do
-> {
eval("-> { _1; -> { _2 } }")
}.should raise_error(SyntaxError, /numbered parameter is already used in/m)
end
ruby_version_is ''...'3.0' do
it "can be overwritten with local variable" do
suppress_warning do
eval <<~CODE
_1 = 0
proc { _1 }.call("a").should == 0
CODE
end
end
it "warns when numbered parameter is overwritten with local variable" do
-> {
eval("_1 = 0")
}.should complain(/warning: `_1' is reserved for numbered parameter; consider another name/)
end
end
ruby_version_is '3.0' do
it "cannot be overwritten with local variable" do
-> {
eval <<~CODE
_1 = 0
proc { _1 }.call("a").should == 0
CODE
}.should raise_error(SyntaxError, /_1 is reserved for numbered parameter/)
end
it "errors when numbered parameter is overwritten with local variable" do
-> {
eval("_1 = 0")
}.should raise_error(SyntaxError, /_1 is reserved for numbered parameter/)
end
end
it "raises SyntaxError when block parameters are specified explicitly" do
-> { eval("-> () { _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("-> (x) { _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("proc { || _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("proc { |x| _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("lambda { || _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("lambda { |x| _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("['a'].map { || _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
-> { eval("['a'].map { |x| _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
end
describe "assigning to a numbered parameter" do
ruby_version_is ''...'3.0' do
it "warns" do
-> { eval("proc { _1 = 0 }") }.should complain(/warning: `_1' is reserved for numbered parameter; consider another name/)
end
end
ruby_version_is '3.0' do
it "raises SyntaxError" do
-> { eval("proc { _1 = 0 }") }.should raise_error(SyntaxError, /_1 is reserved for numbered parameter/)
end
end
end
it "affects block arity" do
-> { _1 }.arity.should == 1
-> { _2 }.arity.should == 2
-> { _3 }.arity.should == 3
-> { _4 }.arity.should == 4
-> { _5 }.arity.should == 5
-> { _6 }.arity.should == 6
-> { _7 }.arity.should == 7
-> { _8 }.arity.should == 8
-> { _9 }.arity.should == 9
-> { _9 }.arity.should == 9
proc { _9 }.arity.should == 9
lambda { _9 }.arity.should == 9
end
it "does not work in methods" do
obj = Object.new
def obj.foo; _1 end
-> { obj.foo("a") }.should raise_error(ArgumentError, /wrong number of arguments/)
end
end
|
