def block(log, token_list, symbol_list, pcode_list):
"""
<分程序>::=[<常量说明部分>][<变量说明部分>][<过程说明部分>]<语句>
"""
# print("# block start")
global address
pre_address = address
start = len(symbol_list)
address = 3
pos: classes.Symbol = symbol_manager.get_level_proc(symbol_list, level)
if start > 0:
pos: classes.Symbol = symbol_manager.get_level_proc(symbol_list, level)
temp_pcode_ptr = len(pcode_list)
temp_pcode = classes.Pcode("JMP", 0, 0)
pcode_list.append(temp_pcode)
if token_list[token_ptr].value == "const":
con_declare(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == "var":
var_declare(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == "const":
error(log, 26, token_list)
con_declare(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == "procedure":
proc(log, token_list, symbol_list, pcode_list)
pcode_list[temp_pcode_ptr].pa = len(pcode_list)
temp_pcode = classes.Pcode("INT", 0, address)
pcode_list.append(temp_pcode)
if start != 0:
pos.value = len(pcode_list) - 1 - pos.size
statement(log, token_list, symbol_list, pcode_list)
temp_pcode = classes.Pcode("OPR", 0, 0)
pcode_list.append(temp_pcode)
address = pre_address
def term(log, token_list, symbol_list, pcode_list):
"""<项>::=<因子>{<乘法运算符><因子>} <乘法运算符>::=*"""
# print("# term start")
global token_ptr
factor(log, token_list, symbol_list, pcode_list)
while token_list[token_ptr].value == "*" or token_list[
token_ptr].value == "/":
flag = token_list[token_ptr].value
token_ptr += 1
factor(log, token_list, symbol_list, pcode_list)
if flag == "*":
pcode_list.append(classes.Pcode("OPR", 0, 4))
# print("this is *.")
if flag == "/":
pcode_list.append(classes.Pcode("OPR", 0, 5))
def condition(log, token_list, symbol_list, pcode_list):
"""<条件>::=<表达式><关系运算符><表达式> | odd<表达式>"""
# ("# condition start")
global token_ptr
if token_list[token_ptr].value == "odd":
token_ptr += 1
expression(log, token_list, symbol_list, pcode_list)
pcode_list.append(classes.Pcode("OPR", 0, 6))
else:
expression(log, token_list, symbol_list, pcode_list)
temp_token = token_list[token_ptr]
token_ptr += 1
expression(log, token_list, symbol_list, pcode_list)
if temp_token.value == "=":
pcode_list.append(classes.Pcode("OPR", 0, 8))
elif temp_token.value == "<>":
pcode_list.append(classes.Pcode("OPR", 0, 9))
elif temp_token.value == "<":
pcode_list.append(classes.Pcode("OPR", 0, 10))
elif temp_token.value == ">=":
pcode_list.append(classes.Pcode("OPR", 0, 11))
elif temp_token.value == ">":
pcode_list.append(classes.Pcode("OPR", 0, 12))
elif temp_token.value == "<=":
pcode_list.append(classes.Pcode("OPR", 0, 13))
else:
error(log, 2, token_list)
def expression(log, token_list, symbol_list, pcode_list):
"""<表达式>::=[+|-]<项>{<加法运算符><项>} <加法运算符>::=+|-"""
# print("# expression start")
global token_ptr
flag = ""
if token_list[token_ptr].value == "+" or token_list[token_ptr].value == "-":
flag = token_list[token_ptr].value
token_ptr += 1
term(log, token_list, symbol_list, pcode_list)
if flag == "-":
pcode_list.append(classes.Pcode("OPR", 0, 1))
# print("this is a negative number.")
while token_list[token_ptr].value == "+" or token_list[
token_ptr].value == "-":
flag = token_list[token_ptr].value
token_ptr += 1
term(log, token_list, symbol_list, pcode_list)
if flag == "-":
pcode_list.append(classes.Pcode("OPR", 0, 3))
if flag == "+":
pcode_list.append(classes.Pcode("OPR", 0, 2))
def factor(log, token_list, symbol_list, pcode_list):
"""<因子>::=<标识符> | <无符号整数> | '('<表达式>')'"""
# print("# factor start")
global token_ptr
if token_list[token_ptr].symtype == 6:
pcode_list.append(
classes.Pcode("LIT", 0, int(token_list[token_ptr].value)))
# print("这是个常数")
token_ptr += 1
elif token_list[token_ptr].value == "(":
token_ptr += 1
expression(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == ")":
token_ptr += 1
else:
error(log, 5, token_list)
elif token_list[token_ptr].symtype == 2:
name = token_list[token_ptr].value
if symbol_manager.exist_pre(symbol_list, name, level) == 0:
error(log, 10, token_list)
token_ptr += 1
return
else:
temp_symbol = symbol_manager.get_symbol(symbol_list, name, level)
if temp_symbol.symtype == 2:
pcode_list.append(
classes.Pcode("LOD", level - temp_symbol.level,
temp_symbol.address))
# print("这是个变量")
elif temp_symbol.symtype == 1:
pcode_list.append(classes.Pcode("LIT", 0, temp_symbol.value))
# print("这是个常量")
else:
error(log, 12, token_list)
return
token_ptr += 1
else:
error(log, 1, token_list)
return
def statement(log, token_list, symbol_list, pcode_list):
"""
<语句>::=<赋值语句> | <条件语句> | <当循环语句> | <过程调用语句> | <复合语句> | <读语句> | <写语句> | <空>
no pcode part
"""
# print("# statement start")
global token_ptr
if token_list[token_ptr].value == "if":
token_ptr += 1
condition(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == "then":
temp_pcode_1 = classes.Pcode("JPC", 0, 0)
pcode_list.append(temp_pcode_1)
token_ptr += 1
statement(log, token_list, symbol_list, pcode_list)
temp_pcode_1.pa = len(pcode_list)
if token_list[token_ptr].value == "else":
token_ptr += 1
temp_pcode_2 = classes.Pcode("JMP", 0, 0)
pcode_list.append(temp_pcode_2)
statement(log, token_list, symbol_list, pcode_list)
temp_pcode_2.pa = len(pcode_list)
else:
error(log, 8, token_list)
return
elif token_list[token_ptr].value == "while":
"""<当循环语句>::=while<条件>do<语句>"""
pos_1 = len(pcode_list)
token_ptr += 1
condition(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == "do":
pos_2 = len(pcode_list)
temp_pcode_2 = classes.Pcode("JPC", 0, 0)
pcode_list.append(temp_pcode_2)
token_ptr += 1
statement(log, token_list, symbol_list, pcode_list)
pcode_list.append(classes.Pcode("JMP", 0, pos_1))
temp_pcode_2.pa = len(pcode_list)
else:
error(log, 9, token_list)
return
elif token_list[token_ptr].value == "call":
"""<过程调用语句>::=call<标识符>"""
token_ptr += 1
if token_list[token_ptr].symtype == 2:
name = token_list[token_ptr].value
if symbol_manager.exist_pre(symbol_list, name, level):
if symbol_manager.get_symbol(symbol_list, name,
level).symtype == 3:
# print("this is a call to procedure" + name)
pcode_list.append(
classes.Pcode(
"CAL", level - symbol_manager.get_symbol(
symbol_list, name, level).level,
symbol_manager.get_symbol(symbol_list, name,
level).value))
else:
error(log, 11, token_list)
return
else:
error(log, 10, token_list)
return
token_ptr += 1
else:
error(log, 1, token_list)
return
elif token_list[token_ptr].value == "read":
"""<读语句>::=read'('<标识符>{,<标识符>}')'"""
token_ptr += 1
if token_list[token_ptr].value == "(":
token_ptr += 1
if token_list[token_ptr].symtype == 2:
name = token_list[token_ptr].value
if symbol_manager.exist_pre(symbol_list, name, level) == 0:
error(log, 10, token_list)
return
else:
temp_symbol = symbol_manager.get_symbol(
symbol_list, name, level)
if temp_symbol.symtype == 2:
# pcode_list.append(classes.Pcode("OPR", 0, 16))
pcode_list.append(
classes.Pcode("RED", level - temp_symbol.level,
temp_symbol.address))
# print("read something into a variable")
else:
error(log, 12, token_list)
return
token_ptr += 1
while token_list[token_ptr].value == ",":
token_ptr += 1
if token_list[token_ptr].symtype == 2:
name = token_list[token_ptr].value
if symbol_manager.exist_pre(symbol_list, name, level) == 0:
error(log, 10, token_list)
return
else:
temp_symbol = symbol_manager.get_symbol(
symbol_list, name, level)
if temp_symbol.symtype == 2:
# pcode_list.append(classes.Pcode("OPR", 0, 16))
# pcode_list.append(classes.Pcode("STO", level - temp_symbol.level, temp_symbol.address))
pcode_list.append(
classes.Pcode("RED", level - temp_symbol.level,
temp_symbol.address))
# print("read something into a variable")
else:
error(log, 12, token_list)
return
token_ptr += 1
else:
error(log, 1, token_list)
return
if token_list[token_ptr].value == ")":
token_ptr += 1
# print("end of a read statement.")
else:
error(log, 5, token_list)
else:
error(log, 4, token_list)
elif token_list[token_ptr].value == "write":
"""<写语句>::=write '('<表达式>{,<表达式>}')'"""
token_ptr += 1
if token_list[token_ptr].value == "(":
token_ptr += 1
expression(log, token_list, symbol_list, pcode_list)
# pcode_list.append(classes.Pcode("OPR", 0, 14))
pcode_list.append(classes.Pcode("WRT", 0, 0))
while token_list[token_ptr].value == ",":
token_ptr += 1
expression(log, token_list, symbol_list, pcode_list)
pcode_list.append(classes.Pcode("WRT", 0, 0))
# pcode_list.append(classes.Pcode("OPR", 0, 15))
if token_list[token_ptr].value == ")":
token_ptr += 1
else:
error(log, 5, token_list)
while token_list[token_ptr].value not in first and token_list[
token_ptr].symtype != 2:
token_ptr += 1
token_ptr -= 1
else:
error(log, 4, token_list)
elif token_list[token_ptr].value == "begin":
"""复合语句"""
body(log, token_list, symbol_list, pcode_list)
elif token_list[token_ptr].symtype == 2:
"""<赋值语句>::=<标识符>:=<表达式>"""
name = token_list[token_ptr].value
token_ptr += 1
if token_list[token_ptr].value == "=" or token_list[
token_ptr].value == ":=" or token_list[token_ptr].value == ":":
if token_list[token_ptr].value == "=" or token_list[
token_ptr].value == ":":
error(log, 24, token_list)
token_ptr += 1
expression(log, token_list, symbol_list, pcode_list)
if symbol_manager.exist_pre(symbol_list, name, level) == 0:
error(log, 14, token_list)
return
else:
temp_symbol = symbol_manager.get_symbol(
symbol_list, name, level)
if temp_symbol.symtype == 2:
pcode_list.append(
classes.Pcode("STO", level - temp_symbol.level,
temp_symbol.address))
# print("fuzhi ok")
else:
error(log, 13, token_list)
else:
error(log, 25, token_list)
elif token_list[token_ptr].value == "repeat":
"""<重复语句> ::= repeat<语句>{;<语句>}until<条件>"""
token_ptr += 1
pos = len(pcode_list)
statement(log, token_list, symbol_list, pcode_list)
while token_list[token_ptr].value == ";" or is_head_of_statement(
token_list):
if is_head_of_statement(token_list) == 1:
error(log, 1, token_list)
else:
token_ptr += 1
if token_list[token_ptr].value == "until":
error(log, 22, token_list)
token_ptr += 1
statement(log, token_list, symbol_list, pcode_list)
if token_list[token_ptr].value == "until":
token_ptr += 1
condition(log, token_list, symbol_list, pcode_list)
pcode_list.append("JPC", 0, pos)
else:
error(log, 19, token_list)
return
con_declare(log, token_list, symbol_list, pcode_list)
else:
error(log, 1, token_list)