def parse_vars(tokens, idx):
# <id> "[" <exp> "]"
old_idx = idx
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
id_name = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, '[')
idx, index_expression = parse_expression(tokens, idx)
idx, tok = utils.match(tokens, idx, OPERATOR, ']')
return idx, ArrayVariable(id_name=id_name,
index_expression=index_expression)
except:
idx = old_idx
# <id>
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
return idx, Variable(id_name=tok.value)
except:
pass
assert False
def parse_single_declaration(tokens, idx):
# <single_declaration> ::= <id> "[" <exp>(a num) "]" | <id> [ '=' <exp> ]
old_idx = idx
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
id_name = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, '[')
idx, tok = utils.match_type(tokens, idx, INT)
index_expression = Number(num=int(tok.value))
idx, tok = utils.match(tokens, idx, OPERATOR, ']')
return idx, SingleArrayDeclaration(id_name=id_name,
index_expression=index_expression)
except:
idx = old_idx
old_idx = idx
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
id_name = tok.value
try:
idx, tok = utils.match(tokens, idx, OPERATOR, '=')
idx, expression = parse_subexpression(tokens, idx)
return idx, SingleDeclaration(id_name=id_name,
expression=expression)
except:
pass
return idx, SingleDeclaration(id_name=id_name, expression=None)
except:
idx = old_idx
assert False
def parse_function(tokens, idx):
# <function> ::= "int" <id> "(" [ "int" <id> { "," "int" <id> } ] ")" ( "{" { <block-item> } "}" | ";" )
idx, tok = utils.match(tokens, idx, RESERVED, 'int')
rtype = tok.value
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
fname = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, '(')
idx, parameters = parse_parameter_list(tokens, idx)
idx, tok = utils.match(tokens, idx, OPERATOR, ')')
# if it is declaration
try:
idx, tok = utils.match(tokens, idx, OPERATOR, ';')
return idx, Function_Declaration(fname=fname,
rtype=rtype,
parameters=parameters,
function=None)
except:
pass
# else it is defination
idx, tok = utils.match(tokens, idx, OPERATOR, '{')
# sub statement
idx, statement = parse_block_item(tokens, idx)
function = Function(fname=fname,
rtype=rtype,
statement=statement,
parameters=parameters,
function=None)
# more statement
while True:
if tokens[idx].value == '}':
break
# print(idx, tokens[idx])
idx, statement = parse_block_item(tokens, idx)
function = Function(fname=fname,
rtype=rtype,
statement=statement,
parameters=parameters,
function=function)
idx, tok = utils.match(tokens, idx, OPERATOR, '}')
# add default return
if 'astnodes.Return' not in str(type(function.statement)):
function = Function(fname=fname,
rtype=rtype,
statement=Return(),
parameters=parameters,
function=function)
return idx, function
def parse_parameter_list(tokens, idx):
# [ "int" <id> { "," "int" <id> } ]
ret = []
try:
idx, tok1 = utils.match(tokens, idx, RESERVED, 'int')
idx, tok2 = utils.match_type(tokens, idx, IDENTIFIER)
ret.append([tok1, tok2])
old_idx = None
try:
while True:
old_idx = idx
idx, tok = utils.match(tokens, idx, OPERATOR, ',')
idx, tok1 = utils.match(tokens, idx, RESERVED, 'int')
idx, tok2 = utils.match_type(tokens, idx, IDENTIFIER)
ret.append([tok1, tok2])
except:
idx = old_idx
except:
pass
return idx, ret
def parse_global_declaration(tokens, idx):
# <declaration> ::= "int" <id> [ = <exp> ] ";"
try:
idx, tok = utils.match(tokens, idx, RESERVED, 'int')
type_name = tok.value
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
id_name = tok.value
try:
idx, tok = utils.match(tokens, idx, OPERATOR, '=')
idx, tok = utils.match_type(tokens, idx, INT)
val = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, ';')
return idx, GlobalDeclaration(type_name=type_name,
id_name=id_name,
val=val)
except:
pass
idx, tok = utils.match(tokens, idx, OPERATOR, ';')
return idx, Declaration(type_name=type_name, id_name=id_name)
except:
pass
assert False
def parse_func_call(tokens, idx):
# <function-call> ::= id "(" [ <exp> { "," <exp> } ] ")"
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
fname = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, '(')
parameters = []
try:
idx, exp = parse_condition_expression(tokens, idx)
parameters.append(exp)
while True:
old_idx = idx
try:
old_idx = idx
idx, tok = utils.match(tokens, idx, OPERATOR, ',')
# idx, exp = parse_expression(tokens, idx)
idx, exp = parse_condition_expression(
tokens, idx) # fix bugs, no assignment action
parameters.append(exp)
except:
idx = old_idx
break
except:
pass
# print(parameters[0])
idx, tok = utils.match(tokens, idx, OPERATOR, ')')
# print(parameters)
# print(fname, tok)
return idx, Func_Call(fname=fname, parameters=parameters)
except:
pass
assert False
def parse_subexpression(tokens, idx):
# <exp> ::= <id> "=" <exp>
old_idx = idx
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
f_name = tok.value
idx, tok = utils.match_type_values(tokens, idx, OPERATOR,
utils.assign_op)
idx, expression = parse_subexpression(tokens, idx) # b=1,a
assignment = Assignment(id_name=f_name,
expression=expression,
op=tok.value)
return idx, assignment
except:
idx = old_idx
# <id> "[" <exp> "]" "=" <exp>
old_idx = idx
try:
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
f_name = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, '[')
idx, index_expression = parse_expression(tokens, idx)
idx, tok = utils.match(tokens, idx, OPERATOR, ']')
idx, tok = utils.match_type_values(tokens, idx, OPERATOR,
utils.assign_op)
idx, expression = parse_subexpression(tokens, idx)
assignment = ArrayAssignment(id_name=f_name,
expression=expression,
op=tok.value,
index_expression=index_expression)
return idx, assignment
except:
idx = old_idx
# <exp> ::= "*" <id> "=" <exp>
old_idx = idx
try:
idx, tok = utils.match(tokens, idx, OPERATOR, '*')
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
f_name = tok.value
idx, tok = utils.match_type_values(tokens, idx, OPERATOR,
utils.assign_op)
idx, expression = parse_subexpression(tokens, idx) # b=1,a
assignment = CiteAssignment(id_name=f_name,
expression=expression,
op=tok.value)
return idx, assignment
except:
idx = old_idx
# <id> "*" "[" <exp> "]" "=" <exp>
old_idx = idx
try:
idx, tok = utils.match(tokens, idx, OPERATOR, '*')
idx, tok = utils.match_type(tokens, idx, IDENTIFIER)
f_name = tok.value
idx, tok = utils.match(tokens, idx, OPERATOR, '[')
idx, index_expression = parse_expression(tokens, idx)
idx, tok = utils.match(tokens, idx, OPERATOR, ']')
idx, tok = utils.match_type_values(tokens, idx, OPERATOR,
utils.assign_op)
idx, expression = parse_subexpression(tokens, idx)
assignment = ArrayAssignment(id_name=f_name,
expression=expression,
op=tok.value,
index_expression=index_expression)
return idx, assignment
except:
idx = old_idx
# <conditional-exp>
try:
idx, expression = parse_condition_expression(tokens, idx)
expression = Expression(logical_or_expression=expression)
return idx, expression
except:
pass
assert False
def parse_factor(tokens, idx):
# <function-call>
try:
idx, expression = parse_func_call(tokens, idx)
return idx, Factor(expression=expression)
except:
pass
# "(" <exp> ")"
old_idx = idx
try:
idx, tok = utils.match(tokens, idx, OPERATOR, '(')
idx, expression = parse_expression(tokens, idx)
idx, tok = utils.match(tokens, idx, OPERATOR, ')')
return idx, Factor(expression=expression)
except:
idx = old_idx
# <unary_op> <var>
old_idx = idx
try:
idx, tok = utils.match_type_values(tokens, idx, OPERATOR,
utils.unary_op)
idx, var = parse_vars(tokens, idx)
return idx, UnaryOP(op=tok.value, factor=var)
except:
idx = old_idx
# <var> <unary_op>
old_idx = idx
try:
idx, var = parse_vars(tokens, idx)
idx, tok = utils.match_type_values(tokens, idx, OPERATOR,
utils.post_unary_op)
return idx, PostUnaryOP(op=tok.value, factor=var)
except:
idx = old_idx
# <var>
try:
idx, var = parse_vars(tokens, idx)
return idx, var
except:
idx = old_idx
# <int>
try:
idx, tok = utils.match_type(tokens, idx, INT)
return idx, Number(num=int(tok.value))
except:
pass
# <char>
try:
idx, tok = utils.match_type(tokens, idx, CHAR)
return idx, Number(num=ord(tok.value))
except:
pass
# <string>
try:
idx, tok = utils.match_type(tokens, idx, STRING)
return idx, String(string=tok.value)
except:
pass
# print('error: parse_factor')
assert False