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require "spec"
require "string_scanner"
describe StringScanner do
describe "#scan" do
it "returns the string matched and advances the offset" do
s = StringScanner.new("this is a string")
s.scan(/\w+/).should eq("this")
s.scan(' ').should eq(" ")
s.scan("is ").should eq("is ")
s.scan(/\w+\s/).should eq("a ")
s.scan(/\w+/).should eq("string")
end
it "returns nil if it can't match from the offset" do
s = StringScanner.new("test string")
s.scan(/\w+/).should_not be_nil # => "test"
s.scan(/\w+/).should be_nil
s.scan('s').should be_nil
s.scan("string").should be_nil
s.scan(/\s\w+/).should_not be_nil # => " string"
s.scan(/.*/).should_not be_nil # => ""
end
end
describe "#scan_until" do
it "returns the string matched and advances the offset" do
s = StringScanner.new("test string")
s.scan_until(/t /).should eq("test ")
s.offset.should eq(5)
s.scan_until("tr").should eq("str")
s.offset.should eq(8)
s.scan_until('n').should eq("in")
s.offset.should eq(10)
end
it "returns nil if it can't match from the offset" do
s = StringScanner.new("test string")
s.offset = 8
s.scan_until(/tr/).should be_nil
s.scan_until('r').should be_nil
s.scan_until("tr").should be_nil
end
end
describe "#skip" do
it "advances the offset but does not returns the string matched" do
s = StringScanner.new("this is a string")
s.skip(/\w+\s/).should eq(5)
s.offset.should eq(5)
s[0]?.should_not be_nil
s.skip(/\d+/).should eq(nil)
s.offset.should eq(5)
s.skip('i').should eq(1)
s.offset.should eq(6)
s.skip("s ").should eq(2)
s.offset.should eq(8)
s.skip(/\w+\s/).should eq(2)
s.offset.should eq(10)
s.skip(/\w+/).should eq(6)
s.offset.should eq(16)
end
end
describe "#skip_until" do
it "advances the offset but does not returns the string matched" do
s = StringScanner.new("this is a string")
s.skip_until(/not/).should eq(nil)
s.offset.should eq(0)
s[0]?.should be_nil
s.skip_until(/\sis\s/).should eq(8)
s.offset.should eq(8)
s[0]?.should_not be_nil
s.skip_until("st").should eq(4)
s.offset.should eq(12)
s[0]?.should_not be_nil
s.skip_until("ng").should eq(4)
s.offset.should eq(16)
s[0]?.should_not be_nil
end
end
describe "#eos" do
it "it is true when the offset is at the end" do
s = StringScanner.new("this is a string")
s.eos?.should eq(false)
s.skip(/(\w+\s?){4}/)
s.eos?.should eq(true)
end
end
describe "#check" do
it "returns the string matched but does not advances the offset" do
s = StringScanner.new("this is a string")
s.offset = 5
s.check(/\w+\s/).should eq("is ")
s.offset.should eq(5)
s.check(/\w+\s/).should eq("is ")
s.offset.should eq(5)
s.check('i').should eq("i")
s.offset.should eq(5)
s.check("is ").should eq("is ")
s.offset.should eq(5)
end
it "returns nil if it can't match from the offset" do
s = StringScanner.new("test string")
s.check(/\d+/).should be_nil
s.check('0').should be_nil
s.check("01").should be_nil
end
end
describe "#check_until" do
it "returns the string matched and advances the offset" do
s = StringScanner.new("test string")
s.check_until(/tr/).should eq("test str")
s.offset.should eq(0)
s.check_until('r').should eq("test str")
s.offset.should eq(0)
s.check_until("tr").should eq("test str")
s.offset.should eq(0)
s.check_until(/g/).should eq("test string")
s.offset.should eq(0)
s.check_until('g').should eq("test string")
s.offset.should eq(0)
s.check_until("ng").should eq("test string")
s.offset.should eq(0)
end
it "returns nil if it can't match from the offset" do
s = StringScanner.new("test string")
s.offset = 8
s.check_until(/tr/).should be_nil
s.check_until('r').should be_nil
s.check_until("tr").should be_nil
end
end
describe "#rest" do
it "returns the remainder of the string from the offset" do
s = StringScanner.new("this is a string")
s.rest.should eq("this is a string")
s.scan(/this is a /)
s.rest.should eq("string")
s.scan(/string/)
s.rest.should eq("")
end
end
describe "#[]" do
it "allows access to subgroups of the last match" do
s = StringScanner.new("Fri Dec 12 1975 14:39")
regex = /(?<wday>\w+) (?<month>\w+) (?<day>\d+)/
s.scan(regex).should eq("Fri Dec 12")
s[0].should eq("Fri Dec 12")
s[1].should eq("Fri")
s[2].should eq("Dec")
s[3].should eq("12")
s["wday"].should eq("Fri")
s["month"].should eq("Dec")
s["day"].should eq("12")
s.scan(' ').should eq(" ")
s[0].should eq(" ")
s.scan("1975").should eq("1975")
s[0].should eq("1975")
end
it "raises when there is no last match" do
s = StringScanner.new("Fri Dec 12 1975 14:39")
s.scan(/this is not there/)
expect_raises(Exception, "Nil assertion failed") { s[0] }
s.scan('t')
expect_raises(Exception, "Nil assertion failed") { s[0] }
s.scan("this is not there")
expect_raises(Exception, "Nil assertion failed") { s[0] }
end
it "raises when there is no subgroup" do
s = StringScanner.new("Fri Dec 12 1975 14:39")
regex = /(?<wday>\w+) (?<month>\w+) (?<day>\d+)/
s.scan(regex)
s[0].should_not be_nil
expect_raises(IndexError) { s[5] }
expect_raises(KeyError, "Capture group 'something' does not exist") { s["something"] }
s.scan(' ')
s[0].should_not be_nil
expect_raises(IndexError) { s[1] }
expect_raises(KeyError, "Capture group 'something' does not exist") { s["something"] }
s.scan("1975")
s[0].should_not be_nil
expect_raises(IndexError) { s[1] }
expect_raises(KeyError, "Capture group 'something' does not exist") { s["something"] }
end
end
describe "#[]?" do
it "allows access to subgroups of the last match" do
s = StringScanner.new("Fri Dec 12 1975 14:39")
result = s.scan(/(?<wday>\w+) (?<month>\w+) (?<day>\d+)/)
result.should eq("Fri Dec 12")
s[0]?.should eq("Fri Dec 12")
s[1]?.should eq("Fri")
s[2]?.should eq("Dec")
s[3]?.should eq("12")
s["wday"]?.should eq("Fri")
s["month"]?.should eq("Dec")
s["day"]?.should eq("12")
s.scan(' ').should eq(" ")
s[0]?.should eq(" ")
s.scan("1975").should eq("1975")
s[0]?.should eq("1975")
end
it "returns nil when there is no last match" do
s = StringScanner.new("Fri Dec 12 1975 14:39")
s.scan(/this is not there/)
s[0]?.should be_nil
s.scan('t')
s[0]?.should be_nil
s.scan("this is not there")
s[0]?.should be_nil
end
it "raises when there is no subgroup" do
s = StringScanner.new("Fri Dec 12 1975 14:39")
s.scan(/(?<wday>\w+) (?<month>\w+) (?<day>\d+)/)
s[0]?.should_not be_nil
s[5]?.should be_nil
s["something"]?.should be_nil
s.scan(' ')
s[0]?.should_not be_nil
s[1]?.should be_nil
s["something"]?.should be_nil
s.scan("1975")
s[0]?.should_not be_nil
s[1]?.should be_nil
s["something"]?.should be_nil
end
end
describe "#string" do
it { StringScanner.new("foo").string.should eq("foo") }
end
describe "#offset" do
it "returns the current position" do
s = StringScanner.new("this is a string")
s.offset.should eq(0)
s.scan(/\w+/)
s.offset.should eq(4)
end
end
describe "#offset=" do
it "sets the current position" do
s = StringScanner.new("this is a string")
s.offset = 5
s.scan(/\w+/).should eq("is")
end
it "raises on negative positions" do
s = StringScanner.new("this is a string")
expect_raises(IndexError) { s.offset = -2 }
end
end
describe "#inspect" do
it "has information on the scanner" do
s = StringScanner.new("this is a string")
s.inspect.should eq(%(#<StringScanner 0/16 "this " >))
s.scan(/\w+\s/)
s.inspect.should eq(%(#<StringScanner 5/16 "s is " >))
s.scan(/\w+\s/)
s.inspect.should eq(%(#<StringScanner 8/16 "s a s" >))
s.scan(/\w+\s\w+/)
s.inspect.should eq(%(#<StringScanner 16/16 "tring" >))
end
it "works with small strings" do
s = StringScanner.new("hi")
s.inspect.should eq(%(#<StringScanner 0/2 "hi" >))
s.scan(/\w\w/)
s.inspect.should eq(%(#<StringScanner 2/2 "hi" >))
end
end
describe "#peek" do
it "shows the next len characters without advancing the offset" do
s = StringScanner.new("this is a string")
s.offset.should eq(0)
s.peek(4).should eq("this")
s.offset.should eq(0)
s.peek(7).should eq("this is")
s.offset.should eq(0)
end
end
describe "#reset" do
it "resets the scan offset to the beginning and clears the last match" do
s = StringScanner.new("this is a string")
s.scan_until(/str/)
s[0]?.should_not be_nil
s.offset.should_not eq(0)
s.reset
s[0]?.should be_nil
s.offset.should eq(0)
end
end
describe "#terminate" do
it "moves the scan offset to the end of the string and clears the last match" do
s = StringScanner.new("this is a string")
s.scan_until(/str/)
s[0]?.should_not be_nil
s.eos?.should eq(false)
s.terminate
s[0]?.should be_nil
s.eos?.should eq(true)
end
end
end
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