Python SymbolTable.get_return_present方法代码示例

# 需要导入模块: from SymbolTable import SymbolTable [as 别名]
# 或者: from SymbolTable.SymbolTable import get_return_present [as 别名]

#.........这里部分代码省略.........
                    elif function_ret_type == 'float' and ret_type == 'int':
                        pass
                    elif ret_type != function_ret_type:
                        print("Error: Improper returned type, expected %s, got %s: line %s" %
                              (function_ret_type, ret_type, node.lineno))
            else:
                # should not happen...
                print("something bad happened while parsing or checking")
        else:
            print("Error: return instruction outside a function: line %s" % node.lineno)

    def visit_ContinueInstr(self, node):
        if not self.symbol_table.is_inside_loop():
            print("Error: continue instruction outside a loop: line %s" % node.lineno)

    def visit_BreakInstr(self, node):
        if not self.symbol_table.is_inside_loop():
            print("Error: break instruction outside a loop: line %s" % node.lineno)

    def visit_CompoundInstr(self, node):
        self.symbol_table = self.symbol_table.push_scope("CompoundInstr")
        for item in node.declarations:
            self.visit(item)
        for item in node.instructions:
            self.visit(item)
        self.symbol_table = self.symbol_table.pop_scope()

    def visit_BinaryExpr(self, node):
        type_1 = self.get_return_type(node.left)
        if not type_1:
            print("Error: Usage of undeclared variable '%s': line %s" % (self.visit(node.left), node.lineno))
        type_2 = self.get_return_type(node.right)
        if not type_2:
            print("Error: Usage of undeclared variable '%s': line %s" % (self.visit(node.right), node.lineno))
        op = self.visit(node.op)
        ret = self.ttypes[op][type_1][type_2]
        if not ret:
            print("Error: Illegal operation, %s %s %s: line %s" % (type_1, op, type_2, node.left.lineno))
        return ret

    def visit_MethodCallExpr(self, node):
        name = self.visit(node.name)
        fun_def = self.symbol_table.get(name)
        if fun_def:
            if len(fun_def.args) != len(node.args):
                print("Error: Improper number of args in %s call: line %s" % (fun_def.name.name, node.lineno))
            else:
                for (fun_arg, call_arg) in zip(fun_def.args, node.args):
                    fun_arg_type = fun_arg.arg_type.name
                    call_arg_type = self.get_return_type(call_arg)
                    if fun_arg_type and call_arg_type:
                        if fun_arg_type == 'int' and call_arg_type == 'float':
                            print("Warning: Possible loss of precision: passing %s instead of %s: line %s" %
                                  (call_arg_type, fun_arg_type, node.lineno))
                        elif fun_arg_type == 'float' and call_arg_type == 'int':
                            pass
                        elif call_arg_type != fun_arg_type:
                            print("Error: Improper type of args in %s call: line %s" % (name, node.lineno))
                            break
            return fun_def.type.name
        else:
            print("Error: Call of undefined function: '%s': line %s" % (name, node.lineno))

    def visit_FunctionDef(self, node):
        name = self.visit(node.name)
        if self.symbol_table.get(name):
            print("Error: Redefinition of function '%s': line %s" % (name, node.lineno))
        self.symbol_table.put(name, FunctionDefSymbol(node.name, node.return_type, node.args))
        self.symbol_table = self.symbol_table.push_scope("FunctionDef")
        self.symbol_table.put(name, FunctionDefSymbol(node.name, node.return_type, node.args))
        self.symbol_table.function_name = name
        for arg in node.args:
            self.visit(arg)
        self.symbol_table.set_return_present(0)
        self.visit(node.body)
        if not self.symbol_table.get_return_present():
            print("Error: Missing return statement in function '%s' returning %s: line %s" %
                  (name, self.visit(node.return_type), node.lineno))
        self.symbol_table = self.symbol_table.pop_scope()

    def visit_Argument(self, node):
        name = self.visit(node.name)
        if self.symbol_table.name == "FunctionDef":
            self.symbol_table.put(name, VariableSymbol(node.name, node.arg_type))

    def get_return_type(self, node):
        if isinstance(node, AST.Name):
            var = self.symbol_table.get(node.name)
            return None if not var else var.type.name
        return self.visit(node)

    @staticmethod
    def check_type_consistency(node, declared_type, expression_ret_type):
        if declared_type == 'int' and expression_ret_type == 'float':
            print("Warning: Possible loss of precision: assignment of %s to %s: line %s" %
                  (expression_ret_type, declared_type, node.lineno))
        elif declared_type == 'float' and expression_ret_type == 'int':
            pass
        elif declared_type != expression_ret_type:
            print("Error: Assignment of %s to %s: line %s" % (expression_ret_type, declared_type, node.lineno))