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Contents
require_relative '../../spec_helper'
require_relative '../../../lib/rley/syntax/terminal'
require_relative '../../../lib/rley/syntax/non_terminal'
require_relative '../../../lib/rley/syntax/symbol_seq'
# Load the class under test
require_relative '../../../lib/rley/syntax/production'
module Rley # Open this namespace to avoid module qualifier prefixes
module Syntax # Open this namespace to avoid module qualifier prefixes
describe Production do
let(:sentence) { NonTerminal.new('Sentence') }
let(:np) { NonTerminal.new('NP') }
let(:vp) { NonTerminal.new('VP') }
let(:sequence) { [np, vp] }
# Default instantiation rule
subject { Production.new(sentence, sequence) }
context 'Initialization:' do
it 'should be created with a non-terminal and a symbol sequence' do
expect { Production.new(sentence, sequence) }.not_to raise_error
end
it 'should know its lhs' do
expect(subject.lhs).to eq(sentence)
expect(subject.head).to eq(sentence)
end
it 'should know its rhs' do
expect(subject.rhs).to eq(sequence)
expect(subject.body).to eq(sequence)
end
it 'should know whether its rhs is empty' do
expect(subject).not_to be_empty
instance = Production.new(sentence, [])
expect(instance).to be_empty
end
it 'should complain if its lhs is not a non-terminal' do
err = StandardError
msg_prefix = 'Left side of production must be a non-terminal symbol'
msg_suffix = ", found a #{String} instead."
msg = msg_prefix + msg_suffix
expect { Production.new('wrong', sequence) }.to raise_error(err, msg)
end
end # context
end # describe
end # module
end # module
# End of file
Version data entries
37 entries across 37 versions & 1 rubygems