def grammar_grammar():
"""Builds the grammar for the grammar file
"""
# star: '*' | '+'
star = Alternative( "star", Token('*'), Token('+') )
star_opt = KleeneStar ( "star_opt", 0, 1, rule=star )
# rule: SYMBOL ':' alternative
symbol = Sequence( "symbol", Token('SYMBOL'), star_opt )
symboldef = Token( "SYMDEF" )
alternative = Sequence( "alternative" )
rule = Sequence( "rule", symboldef, alternative )
# grammar: rule+
grammar = KleeneStar( "grammar", _min=1, rule=rule )
# alternative: sequence ( '|' sequence )*
sequence = KleeneStar( "sequence", 1 )
seq_cont_list = Sequence( "seq_cont_list", Token('|'), sequence )
sequence_cont = KleeneStar( "sequence_cont",0, rule=seq_cont_list )
alternative.args = [ sequence, sequence_cont ]
# option: '[' alternative ']'
option = Sequence( "option", Token('['), alternative, Token(']') )
# group: '(' alternative ')'
group = Sequence( "group", Token('('), alternative, Token(')'), star_opt )
# sequence: (SYMBOL | STRING | option | group )+
string = Token('STRING')
alt = Alternative( "sequence_alt", symbol, string, option, group )
sequence.args = [ alt ]
return grammar
def repeat(self, star_opt, myrule):
if star_opt.nodes:
rule_name = self.new_name()
tok = star_opt.nodes[0].nodes[0]
if tok.value == '+':
return self.new_item(KleeneStar(rule_name, _min=1,
rule=myrule))
elif tok.value == '*':
return self.new_item(KleeneStar(rule_name, _min=0,
rule=myrule))
else:
raise SyntaxError("Got symbol star_opt with value='%s'" %
tok.value)
return myrule
def build_symbol(self, values):
"""symbol: SYMBOL star?"""
sym = values[0]
star = values[1]
if star is True:
return sym
_min = 0
_max = -1
if star == '*':
_min = 0
elif star == '+':
_min = 1
sym = KleeneStar(self.get_name(), _min, _max, rule=sym)
sym.star = star
debug_rule(sym)
self.items.append(sym)
return sym
def build_symbol( self, values ):
"""symbol: SYMBOL star?"""
sym = values[0]
star = values[1]
if star is True:
return sym
_min = 0
_max = -1
if star=='*':
_min = 0
elif star=='+':
_min = 1
sym = KleeneStar( self.get_name(), _min, _max, rule=sym )
sym.star = star
debug_rule( sym )
self.items.append(sym)
return sym
def grammar_grammar():
"""Builds the grammar for the grammar file
"""
# star: '*' | '+'
star = Alternative("star", Token('*'), Token('+'))
star_opt = KleeneStar("star_opt", 0, 1, rule=star)
# rule: SYMBOL ':' alternative
symbol = Sequence("symbol", Token('SYMBOL'), star_opt)
symboldef = Token("SYMDEF")
alternative = Sequence("alternative")
rule = Sequence("rule", symboldef, alternative)
# grammar: rule+
grammar = KleeneStar("grammar", _min=1, rule=rule)
# alternative: sequence ( '|' sequence )*
sequence = KleeneStar("sequence", 1)
seq_cont_list = Sequence("seq_cont_list", Token('|'), sequence)
sequence_cont = KleeneStar("sequence_cont", 0, rule=seq_cont_list)
alternative.args = [sequence, sequence_cont]
# option: '[' alternative ']'
option = Sequence("option", Token('['), alternative, Token(']'))
# group: '(' alternative ')'
group = Sequence("group", Token('('), alternative, Token(')'), star_opt)
# sequence: (SYMBOL | STRING | option | group )+
string = Token('STRING')
alt = Alternative("sequence_alt", symbol, string, option, group)
sequence.args = [alt]
return grammar
def visit_option(self, node):
rule = node.nodes[1].visit(self)
return self.new_item(KleeneStar(self.new_name(), 0, 1, rule))
def build_option(self, values):
"""option: '[' alternative ']'"""
sym = KleeneStar(self.get_name(), 0, 1, rule=values[1])
debug_rule(sym)
self.items.append(sym)
return sym
