def B(parent, table, enrty=None): #<分程序>
child = Node('<分程序>')
parent.add(child)
C(child, table)
E(child, table)
if SYM[p] == KEYWORDS['procedure']:
F(child, table)
startAddr = len(code)
if enrty != None:
enrty.adr = startAddr
code.append(Code('INT', 0, table.getSize()))
H(child, table)
code.append(Code('OPR', 0, 0))
return startAddr
def S(parent, table): #<过程调用语句>
global Error
child = Node('<过程调用语句>')
parent.add(child)
if SYM[p] == KEYWORDS['call']:
child.add(Node('call'))
advance()
if SYM[p] == ident:
name1 = Ident(child, table)
advance()
if SYM[p] == DELIMITERS['(']:
child.add(Node('('))
advance()
if SYM[p] == ident or SYM[p] == number:
temp = 3
L(child, table)
code.append(Code('OPR', temp, 29))
while SYM[p] == DELIMITERS[',']:
advance()
temp += 1
L(child, table)
code.append(Code('OPR', temp, 29))
if SYM[p] == DELIMITERS[')']:
child.add(Node(')'))
advance()
else:
print(Position[p], "缺少右括号")
Error = 1
elif SYM[p] == DELIMITERS[')']:
child.add(Node(')'))
advance()
else:
print(Position[p], "缺少右括号")
Error = 1
else:
print(Position[p], "call后面缺少括号")
Error = 1
(l, a, _) = table.find(name1)
if a == 0:
print(Position[p], '错误，未定义的标识符', name1)
Error = 1
code.append(Code('CAL', l, a))
else:
print(Position[p], "call后面缺少ident")
Error = 1
else:
print(Position[p], "递归错误！")
exit(-1)
def I(parent, table): #<赋值语句>
global Error
if SYM[p] == ident:
child = Node('<赋值语句>')
parent.add(child)
name = Ident(child, table)
advance()
if SYM[p] != OPERATORS[':=']:
print(Position[p], "赋值号错误！")
Error = 1
child.add(Node(':='))
advance()
L(child, table)
(l, a, flag) = table.find(name)
if a == 0:
print(Position[p], '错误，未定义的标识符', name)
Error = 1
if flag == isConst:
print(Position[p], '对常量的非法赋值:' + name)
Error = 1
else:
code.append(Code('STO', l, a))
else:
print(Position[p], '递归错误')
error()
def K(parent, table): #<条件>
child = Node('<条件>')
parent.add(child)
if SYM[p] == OPERATORS['+'] or SYM[p] == OPERATORS['-'] or SYM[
p] == ident or SYM[p] == number or SYM[p] == DELIMITERS['(']:
L(child, table)
opr = Q(child, table)
L(child, table)
code.append(Code('OPR', 0, opr))
elif SYM[p] == OPERATORS['odd']:
child.add(Node('odd'))
advance()
L(child, table)
code.append(Code('OPR', 0, OPERATORS['odd']))
else:
error()
def M(parent, table): #<项>
child = Node('<项>')
parent.add(child)
N(child, table)
while SYM[p] == OPERATORS['*'] or SYM[p] == OPERATORS['/']: # 先乘除，后加减
opr = SYM[p]
P(child, table)
N(child, table)
code.append(Code('OPR', 0, opr))
def K(parent, table): #<条件>
child = Node('<条件>')
parent.add(child)
if SYM[p] == OPERATORS['+'] or SYM[p] == OPERATORS['-'] or SYM[
p] == ident or SYM[p] == number or SYM[p] == DELIMITERS['(']:
L(child, table)
opr = Q(child, table)
L(child, table)
code.append(Code('OPR', 0, opr))
elif SYM[p] == OPERATORS['odd']:
child.add(Node('odd'))
advance()
L(child, table)
code.append(Code('OPR', 0, OPERATORS['odd']))
else:
print(Position[p], "无法识别的条件判断")
global Error
Error = 1
def R(parent, table): #<条件语句>
child = Node('<条件语句>')
parent.add(child)
if SYM[p] == KEYWORDS['if']:
child.add(Node('if'))
advance()
K(child, table)
ret = Code('JPC', 0, None)
code.append(ret)
if SYM[p] == KEYWORDS['then']:
child.add(Node('then'))
advance()
H(child, table)
ret.a = len(code)
else:
error()
else:
error()
def U(parent, table): #<读语句>
child = Node('<读语句>')
parent.add(child)
if SYM[p] == OPERATORS['read']:
child.add(Node('read'))
advance()
if SYM[p] == DELIMITERS['(']:
child.add(Node('('))
advance()
if SYM[p] == ident:
name = X(child, table)
advance()
code.append(Code('OPR', 0, OPERATORS['read']))
(l, a, flag) = table.find(name)
if flag == isConst:
print('对常量的非法赋值:' + name)
else:
code.append(Code('STO', l, a))
while SYM[p] == DELIMITERS[',']:
child.add(Node(','))
advance()
if SYM[p] == ident:
name = X(child, table)
advance()
code.append(Code('OPR', 0, OPERATORS['read']))
(l, a, flag) = table.find(name)
if flag == isConst:
print('对常量的非法赋值:' + name)
else:
code.append(Code('STO', l, a))
else:
error()
if SYM[p] == DELIMITERS[')']:
child.add(Node(')'))
advance()
else:
error()
else:
error()
else:
error()
else:
error()
def T(parent, table): #<当型循环语句>
child = Node('<当型循环语句>')
parent.add(child)
if SYM[p] == KEYWORDS['while']:
child.add(Node('while'))
advance()
ret = len(code)
K(child, table)
fret = Code('JPC', 0, None)
code.append(fret)
if SYM[p] == KEYWORDS['do']:
child.add(Node('do'))
advance()
H(child, table)
code.append(Code('JMP', 0, ret))
fret.a = len(code)
else:
error()
else:
error()
def L(parent, table): #<表达式>
child = Node('<表达式>')
parent.add(child)
if SYM[p] == OPERATORS['+']:
child.add(Node('+'))
advance()
M(child, table)
elif SYM[p] == OPERATORS['-']:
child.add(Node('-'))
advance()
M(child, table)
code.append(Code('LIT', 0, -1))
code.append(Code('OPR', 0, OPERATORS['*'])) #如果是-号做取负运算
else:
M(child, table)
while SYM[p] == OPERATORS['+'] or SYM[p] == OPERATORS['-']:
opr = SYM[p]
O(child, table)
M(child, table)
code.append(Code('OPR', 0, opr))
def B(parent, table, enrty=None): #<分程序>
global p
if SYM[p] != KEYWORDS['const'] and SYM[p] != KEYWORDS['var'] and SYM[
p] != KEYWORDS['procedure'] and SYM[p] != KEYWORDS['begin']:
print(Position[p], 'block中需要关键词const or var or procedure or begin')
global Error
Error = 1
while p < len(SYM) - 1 and SYM[p] != KEYWORDS['const'] and SYM[
p] != KEYWORDS['var'] and SYM[p] != KEYWORDS['procedure']:
p += 1
child = Node('<分程序>')
parent.add(child)
Const(child, table)
E(child, table)
if SYM[p] == KEYWORDS['procedure']:
F(child, table)
startAddr = len(code)
if enrty != None:
enrty.adr = startAddr
code.append(Code('INT', 0, table.getSize()))
H(child, table)
code.append(Code('OPR', 0, 0))
return startAddr
def T(parent, table): #<当型循环语句>
child = Node('<当型循环语句>')
parent.add(child)
if SYM[p] == KEYWORDS['while']:
child.add(Node('while'))
advance()
ret = len(code)
K(child, table)
fret = Code('JPC', 0, None)
code.append(fret)
if SYM[p] == KEYWORDS['do']:
child.add(Node('do'))
advance()
H(child, table)
code.append(Code('JMP', 0, ret))
fret.a = len(code)
else:
print(Position[p], "while后面缺少do")
global Error
Error = 1
else:
print(Position[p], "递归错误")
error()
def S(parent, table): #<过程调用语句>
child = Node('<过程调用语句>')
parent.add(child)
if SYM[p] == KEYWORDS['call']:
child.add(Node('call'))
advance()
if SYM[p] == ident:
name = X(child, table)
advance()
(l, a, _) = table.find(name)
if l > 1: #当调用超出范围时出错
print('非法的过程调用')
exit(-1)
code.append(Code('CAL', l, a))
else:
error()
else:
error()
def I(parent, table): #<赋值语句>
if SYM[p] == ident:
child = Node('<赋值语句>')
parent.add(child)
name = X(child, table)
advance()
if SYM[p] == OPERATORS[':=']:
child.add(Node(':='))
advance()
L(child, table)
(l, a, flag) = table.find(name)
if flag == isConst:
print('对常量的非法赋值:' + name)
error()
else:
code.append(Code('STO', l, a))
else:
error()
else:
error()
from symbol import KEYWORDS, OPERATORS, DELIMITERS, SYM, ident, number, IDi, NUM, Position
from node import Node
from table import Table, Entry, isConst, KIND
from inst import Code
p = 0
pid = 0
pnum = 0
Error = 0
root = Node('<程序>')
table = Table() #table表
code = [] #CODE数组
startCode = Code('JMP', 0, None)
code.append(startCode)
code.append(Code('JMP', 0, 2))
tableList = []
def error(a=0): # 出错
case = ['0 ']
# print("Error:",p)
exit(-1)
def advance():
global p
p = p + 1
def program():
if SYM[p] == KEYWORDS['program']:
from symbol import KEYWORDS, OPERATORS, DELIMITERS, SYM, ident, number, IDi, NUM
from node import Node
from table import Table, Entry, isConst, KIND
from inst import Code
p = 0
pid = 0
pnum = 0
root = Node('<程序>')
table = Table() #table表
code = [] #CODE数组
startCode = Code('JMP', 0, None)
code.append(startCode)
code.append(Code)
tableList = []
def error(): # 出错
print("Error:", p)
exit(-1)
def advance():
global p
p = p + 1
def block():
tableList.append(table)
A(root, table)