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require 'spec_helper'
ML = Regexp::MatchLength
RSpec.describe(Regexp::MatchLength) do
specify('literal') { expect(ML.of(/a/).minmax).to eq [1, 1] }
specify('literal sequence') { expect(ML.of(/abc/).minmax).to eq [3, 3] }
specify('dot') { expect(ML.of(/./).minmax).to eq [1, 1] }
specify('set') { expect(ML.of(/[abc]/).minmax).to eq [1, 1] }
specify('type') { expect(ML.of(/\d/).minmax).to eq [1, 1] }
specify('escape') { expect(ML.of(/\n/).minmax).to eq [1, 1] }
specify('property') { expect(ML.of(/\p{ascii}/).minmax).to eq [1, 1] }
specify('codepoint list') { expect(ML.of(/\u{61 62 63}/).minmax).to eq [3, 3] }
specify('multi-char literal') { expect(ML.of(/abc/).minmax).to eq [3, 3] }
specify('fixed quantified') { expect(ML.of(/a{5}/).minmax).to eq [5, 5] }
specify('range quantified') { expect(ML.of(/a{5,9}/).minmax).to eq [5, 9] }
specify('nested quantified') { expect(ML.of(/(a{2}){3,4}/).minmax).to eq [6, 8] }
specify('open-end quantified') { expect(ML.of(/a*/).minmax).to eq [0, Float::INFINITY] }
specify('empty subexpression') { expect(ML.of(//).minmax).to eq [0, 0] }
specify('anchor') { expect(ML.of(/^$/).minmax).to eq [0, 0] }
specify('lookaround') { expect(ML.of(/(?=abc)/).minmax).to eq [0, 0] }
specify('free space') { expect(ML.of(/ /x).minmax).to eq [0, 0] }
specify('comment') { expect(ML.of(/(?#comment)/x).minmax).to eq [0, 0] }
specify('backreference') { expect(ML.of(/(abc){2}\1/).minmax).to eq [9, 9] }
specify('subexp call') { expect(ML.of(/(abc){2}\g<-1>/).minmax).to eq [9, 9] }
specify('alternation') { expect(ML.of(/a|bcde/).minmax).to eq [1, 4] }
specify('nested alternation') { expect(ML.of(/a|bc(d|efg)/).minmax).to eq [1, 5] }
specify('quantified alternation') { expect(ML.of(/a|bcde?/).minmax).to eq [1, 4] }
if ruby_version_at_least('2.4.1')
specify('absence group') { expect(ML.of('(?~abc)').minmax).to eq [0, Float::INFINITY] }
end
specify('raises for missing references') do
exp = RP.parse(/(a)\1/).last
exp.referenced_expression = nil
expect { exp.match_length }.to raise_error(ArgumentError)
end
describe('::of') do
it('works with Regexps') { expect(ML.of(/foo/).minmax).to eq [3, 3] }
it('works with Strings') { expect(ML.of('foo').minmax).to eq [3, 3] }
it('works with Expressions') { expect(ML.of(RP.parse(/foo/)).minmax).to eq [3, 3] }
end
describe('Expression::Base#match_length') do
it('returns the MatchLength') { expect(RP.parse(/abc/).match_length.minmax).to eq [3, 3] }
end
describe('Expression::Base#inner_match_length') do
it 'returns the MatchLength of an expression that does not count towards parent match_length' do
exp = RP.parse(/(?=ab|cdef)/)[0]
expect(exp).to be_a Regexp::Expression::Assertion::Base
expect(exp.match_length.minmax).to eq [0, 0]
expect(exp.inner_match_length.minmax).to eq [2, 4]
end
end
describe('#include?') do
specify('unquantified') do
expect(ML.of(/a/)).to include 1
expect(ML.of(/a/)).not_to include 0
expect(ML.of(/a/)).not_to include 2
end
specify('fixed quantified') do
expect(ML.of(/a{5}/)).to include 5
expect(ML.of(/a{5}/)).not_to include 0
expect(ML.of(/a{5}/)).not_to include 4
expect(ML.of(/a{5}/)).not_to include 6
end
specify('variably quantified') do
expect(ML.of(/a?/)).to include 0
expect(ML.of(/a?/)).to include 1
expect(ML.of(/a?/)).not_to include 2
end
specify('nested quantified') do
expect(ML.of(/(a{2}){3,4}/)).to include 6
expect(ML.of(/(a{2}){3,4}/)).to include 8
expect(ML.of(/(a{2}){3,4}/)).not_to include 0
expect(ML.of(/(a{2}){3,4}/)).not_to include 5
expect(ML.of(/(a{2}){3,4}/)).not_to include 7
expect(ML.of(/(a{2}){3,4}/)).not_to include 9
end
specify('branches') do
expect(ML.of(/ab|cdef/)).to include 2
expect(ML.of(/ab|cdef/)).to include 4
expect(ML.of(/ab|cdef/)).not_to include 0
expect(ML.of(/ab|cdef/)).not_to include 3
expect(ML.of(/ab|cdef/)).not_to include 5
end
specify('called on leaf node') do
expect(ML.of(RP.parse(/a{2}/)[0])).to include 2
expect(ML.of(RP.parse(/a{2}/)[0])).not_to include 0
expect(ML.of(RP.parse(/a{2}/)[0])).not_to include 1
expect(ML.of(RP.parse(/a{2}/)[0])).not_to include 3
end
end
describe('#fixed?') do
specify('unquantified') { expect(ML.of(/a/)).to be_fixed }
specify('fixed quantified') { expect(ML.of(/a{5}/)).to be_fixed }
specify('variably quantified') { expect(ML.of(/a?/)).not_to be_fixed }
specify('equal branches') { expect(ML.of(/ab|cd/)).to be_fixed }
specify('unequal branches') { expect(ML.of(/ab|cdef/)).not_to be_fixed }
specify('equal quantified branches') { expect(ML.of(/a{2}|cd/)).to be_fixed }
specify('unequal quantified branches') { expect(ML.of(/a{3}|cd/)).not_to be_fixed }
specify('empty') { expect(ML.of(//)).to be_fixed }
end
describe('#each') do
it 'returns an Enumerator if called without a block' do
result = ML.of(/a?/).each
expect(result).to be_a(Enumerator)
expect(result.next).to eq 0
expect(result.next).to eq 1
expect { result.next }.to raise_error(StopIteration)
end
it 'is aware of limit option even if called without a block' do
result = ML.of(/a?/).each(limit: 1)
expect(result).to be_a(Enumerator)
expect(result.next).to eq 0
expect { result.next }.to raise_error(StopIteration)
end
it 'is limited to 1000 iterations in case there are infinite match lengths' do
expect(ML.of(/a*/).first(3000).size).to eq 1000
end
it 'scaffolds the Enumerable interface' do
expect(ML.of(/abc|defg/).count).to eq 2
expect(ML.of(/(ab)*/).first(5)).to eq [0, 2, 4, 6, 8]
expect(ML.of(/a{,10}/).any? { |len| len > 20 }).to be false
end
end
describe('#endless_each') do
it 'returns an Enumerator if called without a block' do
result = ML.of(/a?/).endless_each
expect(result).to be_a(Enumerator)
expect(result.next).to eq 0
expect(result.next).to eq 1
expect { result.next }.to raise_error(StopIteration)
end
it 'never stops iterating for infinite match lengths' do
expect(ML.of(/a*/).endless_each.first(3000).size).to eq 3000
end
end
describe('#inspect') do
it 'is nice' do
result = RP.parse(/a{2,4}/)[0].match_length
expect(result.inspect).to eq '#<Regexp::MatchLength<Literal> min=2 max=4>'
end
end
end
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