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Changeset 24513

Timestamp:

11/20/08 23:45:10 (7 weeks ago)

Author:

hiratara

Message:

左結合になるようにルールを修正
lexerとparserのインタフェースは変えないようにしてみた
OOPなインタフェースがあんまりだったから整理
左結合になるように修正

Location:

lang/python/dfareg/branches/codezine200809/dfareg

Files:

r21916	r24513
71	71	return frag
72	72
	73	def __str__(self):
	74	return "(%s\|%s)" % (self.operand1, self.operand2)
	75
73	76
74	77	class Concat(object):
…	…
89	92
90	93	return frag
	94	def __str__(self):
	95	return "(%s%s)" % (self.operand1, self.operand2)
	96
91	97
92	98	class Star(object):
…	…
109	115	return frag
110	116
	117	def __str__(self):
	118	return "%s*" % self.operand
	119
111	120	class Character(object):
112	121	def __init__(self, char):
…	…
123	132
124	133	return frag
	134	def __str__(self):
	135	return self.char

r23630	r24513
13	13	----------------------------------------
14	14	expression -> subexpr
15		subexpr -> seq '\|' subexpr \| seq
	15	subexpr -> subexpr '\|' seq \| seq
	16	(
	17	subexpr -> seq _subexpr
	18	_subexpr -> '\|' seq _subexpr \| ε
	19	)
16	20	seq -> subseq \| ε
17		subseq -> star subseq \| star
	21	subseq -> subseq star \| star
	22	(
	23	subseq -> star _subseq
	24	_subseq -> star _subseq \| ε
	25	)
18	26	star -> factor '*' \| factor
19	27	factor -> '(' subexpr ')' \| CHARACTER
…	…
46	54
47	55	def subexpr(self):
48		# subexpr ~~-> seq '\|' subexpr \| seq~~
	56	# subexpr -> seq _subexpr
49	57	node = self.seq()
50		if self.look.kind == Token.OPE_UNION:
51		self.match(Token.OPE_UNION)
52		node2 = self.subexpr()
53		node = Union(node, node2)
	58	while True:
	59	if self.look.kind == Token.OPE_UNION:
	60	# _subexpr -> '\|' seq _subexpr \| ε
	61	self.match(Token.OPE_UNION)
	62	node2 = self.seq()
	63	node = Union(node, node2)
	64	else:
	65	# _subexpr -> ε
	66	break
54	67	return node
55	68
…	…
64	77
65	78	def subseq(self):
66		node1 = self.star()
67		if self.look.kind == Token.LPAREN \
68		or self.look.kind == Token.CHARACTER:
69		# subseq -> star subseq
70		node2 = self.subseq()
71		node = Concat(node1, node2)
72		return node
73		else:
74		# subseq -> star
75		return node1
	79	# subseq -> star _subseq
	80	node = self.star()
	81	while True:
	82	if self.look.kind == Token.LPAREN \
	83	or self.look.kind == Token.CHARACTER:
	84	# _subseq -> star _subseq
	85	node2 = self.star()
	86	node = Concat(node, node2)
	87	continue
	88	else:
	89	# _subseq -> ε
	90	break
	91	return node
76	92
77	93	def star(self):