107 lines
3.7 KiB
Ruby
107 lines
3.7 KiB
Ruby
require_relative '../spec_helper'
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ruby_version_is "2.7" do
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describe "Numbered parameters" do
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it "provides default parameters _1, _2, ... in a block" do
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-> { _1 }.call("a").should == "a"
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proc { _1 }.call("a").should == "a"
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lambda { _1 }.call("a").should == "a"
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["a"].map { _1 }.should == ["a"]
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end
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it "assigns nil to not passed parameters" do
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proc { [_1, _2] }.call("a").should == ["a", nil]
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proc { [_1, _2] }.call("a", "b").should == ["a", "b"]
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end
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it "supports variables _1-_9 only for the first 9 passed parameters" do
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block = proc { [_1, _2, _3, _4, _5, _6, _7, _8, _9] }
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result = block.call(1, 2, 3, 4, 5, 6, 7, 8, 9)
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result.should == [1, 2, 3, 4, 5, 6, 7, 8, 9]
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end
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it "does not support more than 9 parameters" do
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-> {
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proc { [_10] }.call(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
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}.should raise_error(NameError, /undefined local variable or method `_10'/)
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end
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it "can not be used in both outer and nested blocks at the same time" do
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-> {
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eval("-> { _1; -> { _2 } }")
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}.should raise_error(SyntaxError, /numbered parameter is already used in/m)
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end
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ruby_version_is '2.7'...'3.0' do
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it "can be overwritten with local variable" do
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suppress_warning do
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eval <<~CODE
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_1 = 0
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proc { _1 }.call("a").should == 0
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CODE
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end
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end
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it "warns when numbered parameter is overwritten with local variable" do
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-> {
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eval("_1 = 0")
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}.should complain(/warning: `_1' is reserved for numbered parameter; consider another name/)
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end
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end
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ruby_version_is '3.0' do
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it "cannot be overwritten with local variable" do
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-> {
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eval <<~CODE
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_1 = 0
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proc { _1 }.call("a").should == 0
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CODE
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}.should raise_error(SyntaxError, /_1 is reserved for numbered parameter/)
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end
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it "errors when numbered parameter is overwritten with local variable" do
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-> {
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eval("_1 = 0")
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}.should raise_error(SyntaxError, /_1 is reserved for numbered parameter/)
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end
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end
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it "raises SyntaxError when block parameters are specified explicitly" do
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-> { eval("-> () { _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("-> (x) { _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("proc { || _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("proc { |x| _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("lambda { || _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("lambda { |x| _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("['a'].map { || _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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-> { eval("['a'].map { |x| _1 }") }.should raise_error(SyntaxError, /ordinary parameter is defined/)
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end
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it "affects block arity" do
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-> { _1 }.arity.should == 1
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-> { _2 }.arity.should == 2
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-> { _3 }.arity.should == 3
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-> { _4 }.arity.should == 4
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-> { _5 }.arity.should == 5
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-> { _6 }.arity.should == 6
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-> { _7 }.arity.should == 7
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-> { _8 }.arity.should == 8
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-> { _9 }.arity.should == 9
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-> { _9 }.arity.should == 9
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proc { _9 }.arity.should == 9
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lambda { _9 }.arity.should == 9
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end
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it "does not work in methods" do
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obj = Object.new
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def obj.foo; _1 end
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-> { obj.foo("a") }.should raise_error(ArgumentError, /wrong number of arguments/)
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end
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end
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end
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