How to use the ply.yacc.YaccSymbol function in ply
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dabeaz / ply / ply / yacc.py View on Github 
sym = YaccSymbol()
sym.type = '$end'
symstack.append(sym)
state = 0
while 1:
# Get the next symbol on the input. If a lookahead symbol
# is already set, we just use that. Otherwise, we'll pull
# the next token off of the lookaheadstack or from the lexer
if not lookahead:
if not lookaheadstack:
lookahead = get_token() # Get the next token
else:
lookahead = lookaheadstack.pop()
if not lookahead:
lookahead = YaccSymbol()
lookahead.type = '$end'
# Check the action table
ltype = lookahead.type
t = actions[state].get(ltype)
if t is not None:
if t > 0:
# shift a symbol on the stack
statestack.append(t)
state = t
symstack.append(lookahead)
lookahead = None
# Decrease error count on successful shiftdef restart(self):
del self.statestack[:]
del self.symstack[:]
sym = YaccSymbol()
sym.type = '$end'
self.symstack.append(sym)
self.statestack.append(0)# case 2: the statestack has a couple of entries on it, but we're
# at the end of the file. nuke the top entry and generate an error token
# Start nuking entries on the stack
if lookahead.type == '$':
# Whoa. We're really hosed here. Bail out
return
if lookahead.type != 'error':
sym = symstack[-1]
if sym.type == 'error':
# Hmmm. Error is on top of stack, we'll just nuke input
# symbol and continue
lookahead = None
continue
t = YaccSymbol()
t.type = 'error'
if hasattr(lookahead,"lineno"):
t.lineno = lookahead.lineno
t.value = lookahead
lookaheadstack.append(lookahead)
lookahead = t
else:
symstack.pop()
statestack.pop()
continue
# Call an error function here
raise RuntimeError, "yacc: internal parser error!!!\n"sym = YaccSymbol()
sym.type = '$end'
symstack.append(sym)
state = 0
while 1:
# Get the next symbol on the input. If a lookahead symbol
# is already set, we just use that. Otherwise, we'll pull
# the next token off of the lookaheadstack or from the lexer
if not lookahead:
if not lookaheadstack:
lookahead = get_token() # Get the next token
else:
lookahead = lookaheadstack.pop()
if not lookahead:
lookahead = YaccSymbol()
lookahead.type = '$end'
# Check the action table
ltype = lookahead.type
t = actions[state].get(ltype)
if t is not None:
if t > 0:
# shift a symbol on the stack
statestack.append(t)
state = t
symstack.append(lookahead)
lookahead = None
# Decrease error count on successful shift# case 2: the statestack has a couple of entries on it, but we're
# at the end of the file. nuke the top entry and generate an error token
# Start nuking entries on the stack
if self.lookahead.type == "$end":
# Whoa. We're really hosed here. Bail out
return
if self.lookahead.type != "error":
sym = symstack[-1]
if sym.type == "error":
# Hmmm: error is on top of stack, we'll just nuke input
# symbol and continue
self.lookahead = None
continue
t = YaccSymbol()
t.type = "error"
if hasattr(self.lookahead, "lineno"):
t.lineno = self.lookahead.lineno
t.value = self.lookahead
self.lookaheadstack.append(self.lookahead)
self.lookahead = t
else:
symstack.pop()
statestack.pop()
state = statestack[-1] # Potential bug fix
continue
# Call an error function here
raise RuntimeError("yacc: internal parser error!!!\n")symstack.append(lookahead)
lookahead = None
# Decrease error count on successful shift
if errorcount: errorcount -=1
continue
if t < 0:
# reduce a symbol on the stack, emit a production
p = prod[-t]
pname = p.name
plen = p.len
# Get production function
sym = YaccSymbol()
sym.type = pname # Production name
sym.value = None
if plen:
targ = symstack[-plen-1:]
targ[0] = sym
# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
# The code enclosed in this section is duplicated
# below as a performance optimization. Make sure
# changes get made in both locations.
pslice.slice = targ
try:
# Call the grammar rule with our special slice objectsymstack.append(lookahead)
lookahead = None
# Decrease error count on successful shift
if errorcount: errorcount -=1
continue
if t < 0:
# reduce a symbol on the stack, emit a production
p = prod[-t]
pname = p.name
plen = p.len
# Get production function
sym = YaccSymbol()
sym.type = pname # Production name
sym.value = None
# --! DEBUG
if plen:
debug.info("Action : Reduce rule [%s] with %s and goto state %d", p.str, "["+",".join([format_stack_entry(_v.value) for _v in symstack[-plen:]])+"]",-t)
else:
debug.info("Action : Reduce rule [%s] with %s and goto state %d", p.str, [],-t)
# --! DEBUG
if plen:
targ = symstack[-plen-1:]
targ[0] = sym
# --! TRACKING# Get the next symbol on the input. If a lookahead symbol
# is already set, we just use that. Otherwise, we'll pull
# the next token off of the lookaheadstack or from the lexer
# --! DEBUG
# debug.debug('')
# debug.debug('State : %s', state)
# --! DEBUG
if not self.lookahead:
if not self.lookaheadstack:
self.lookahead = get_token() # Get the next token
else:
self.lookahead = self.lookaheadstack.pop()
if not self.lookahead:
self.lookahead = YaccSymbol()
self.lookahead.type = "$end"
# --! DEBUG
# debug.debug('Stack : %s',
# ("%s . %s" % (" ".join([xx.type for xx in symstack][1:]), str(self.lookahead))).lstrip())
# --! DEBUG
# Check the action table
ltype = self.lookahead.type
t = actions[state].get(ltype)
# This is a bad hack to deal with LilyPond's backup/reparse regime
if t is None:
a = set(actions[state].values( ))
if 1 == len(a):
t = list(a)[0]# Get the next symbol on the input. If a lookahead symbol
# is already set, we just use that. Otherwise, we'll pull
# the next token off of the lookaheadstack or from the lexer
# --! DEBUG
debug.debug("")
debug.debug("State : %s", state)
# --! DEBUG
if not self.lookahead:
if not self.lookaheadstack:
self.lookahead = get_token() # Get the next token
else:
self.lookahead = self.lookaheadstack.pop()
if not self.lookahead:
self.lookahead = YaccSymbol()
self.lookahead.type = "$end"
# --! DEBUG
debug.debug(
"Stack : %s",
(
"%s . %s"
% (" ".join([xx.type for xx in symstack][1:]), str(self.lookahead),)
).lstrip(),
)
# --! DEBUG
# Check the action table
ltype = self.lookahead.type
t = actions[state].get(ltype)
