import unittest, pprint
from pyyacc import Grammar, Item, EOF 


class testLR(unittest.TestCase):
    def setUp(self):
        pass

    def testSimpleGrammar(self):
        # 1. define a simple grammar:
        g = Grammar(['EOF', 'identifier', '(', ')', '+', '*'])
        g.add_production('input', ['expression'])
        g.add_production('expression', ['term'])
        g.add_production('expression', ['expression', '+', 'term'])
        g.add_production('term', ['factor'])
        g.add_production('term', ['term', '*', 'factor'])
        g.add_production('factor', ['(', 'expression', ')'])
        g.add_production('factor', ['identifier'])
        g.start_symbol = 'input'
        # 2. define input:
        tokens = ['identifier', '+', 'identifier', '+', 'identifier', 'EOF']
        # 3. build parser:
        p = g.genParser()
        # 4. feed input:
        p.parse(tokens)

class testPG(unittest.TestCase):
    """ Tests several parts of the parser generator """
    def setUp(self):
        g = Grammar(['(', ')'])
        g.add_production('goal', ['list'])
        g.add_production('list', ['list', 'pair'])
        g.add_production('list', ['pair'])
        g.add_production('pair', ['(', 'pair', ')'])
        g.add_production('pair', ['(', ')'])
        g.start_symbol = 'goal'
        g.first = g.calcFirstSets()
        self.g = g

    def testFirstSet(self):
        for a in ['(', ')', EOF, 'EPS']:
            self.assertEqual(self.g.first[a], {a})
        for nt in ['list', 'pair', 'goal']:
            self.assertEqual(self.g.first[nt], {'('})

    def testInitItemSet(self):
        p0, p1, p2, p3, p4 = self.g.productions
        s0 = self.g.initialItemSet()
        self.assertEqual(len(s0), 9)    # 9 with the goal rule included!
        self.assertIn(Item(p0, 0, EOF), s0)
        self.assertIn(Item(p1, 0, EOF), s0)
        self.assertIn(Item(p1, 0, '('), s0)
        self.assertIn(Item(p2, 0, EOF), s0)
        self.assertIn(Item(p2, 0, '('), s0)
        self.assertIn(Item(p3, 0, EOF), s0)
        self.assertIn(Item(p3, 0, '('), s0)
        self.assertIn(Item(p4, 0, EOF), s0)
        self.assertIn(Item(p4, 0, '('), s0)

    def testCanonical(self):
        s0 = self.g.initialItemSet()
        s, gt = self.g.genCanonicalSet(s0)
        pprint.pprint(s)
        # Must result in 12 sets:
        self.assertEqual(len(s), 12)

    def testClosure(self):
        p0, p1, p2, p3, p4 = self.g.productions
        s0 = set()
        for p in self.g.productionsForName(self.g.start_symbol):
            s0.add(Item(p, 0, EOF))
        self.assertEqual(len(s0), 1)    # 1 rule
        self.assertIn(Item(p0, 0, EOF), s0)

        # Invoke closure on set:
        s0 = self.g.closure(s0)
        self.assertIn(Item(p0, 0, EOF), s0)
        self.assertIn(Item(p1, 0, EOF), s0)
        self.assertIn(Item(p1, 0, '('), s0)
        self.assertIn(Item(p2, 0, EOF), s0)
        self.assertIn(Item(p2, 0, '('), s0)
        self.assertIn(Item(p3, 0, EOF), s0)
        self.assertIn(Item(p3, 0, '('), s0)
        self.assertIn(Item(p4, 0, EOF), s0)
        self.assertIn(Item(p4, 0, '('), s0)

    def testParser(self):
        tokens = ['(', '(', ')', '(', ')', ')', 'EOF']
        # 3. build parser:
        p = self.g.genParser()
        # 4. feed input:
        p.parse(tokens)

if __name__ == '__main__':
    unittest.main()