可以处理语法错误吗？

问题描述

考虑以下代码：

try:
    if True a = 1  #It's missing a colon So it's a SyntaxError!!!!!!!
except SyntaxError:
    print 'hey'

您期望它打印嘿但是它会引发 SyntaxError ，这是我想避免的错误。那么可以使用 try-except 块来处理所有异常吗？好吧，如果 SyntaxError 是一个例外，为什么将它包含在？最后如何解决上面的代码，以便它可以正确处理异常？

You'd expect it to print hey However It raises a SyntaxError, The same error I'm trying to avoid. So Can all Exceptions be handled using a try-except block? Well If SyntaxError's were an exception why is it included in the built-in exceptions? and finally how can I fix the above piece of code so that it handles the exception properly?

注意：我知道我要做什么完全是没有意义，没有实际目的

推荐答案

SyntaxError 是一个完全普通的内置异常。它在任何方面都不是特别的。

SyntaxError is a perfectly ordinary built-in exception. It is not special in any way. Only the circumstances of when it's (usually) thrown are a bit unusual.

语法错误意味着无法解析带有该错误的代码 。它甚至还不是一个有效的程序，因此无法执行。因此，在程序运行之前，在 之前引发了 SyntaxError 异常，因此无法从程序中捕获该异常。

A syntax error means that the code featuring said error cannot be parsed. It doesn't even begin to be a valid program, hence it cannot be executed. Therefore SyntaxError exceptions are raised before the program is run, and hence can't be caught from within the program.

更具体地说，此异常是由解析器引发的。因为解析器在代码执行之前就完全运行，而不是与之交错，所以程序无法捕获其自身的语法错误。

More specifically, this exception is raised by the parser. Because the parser runs fully before the code is executed, rather then interleaved with it, a program can't catch its own syntax errors.

解析器本身就是另一个程序但是：调用解析器的代码可以像其他所有异常一样捕获 SyntaxError （因为 is 与其他所有异常一样）。 调用解析器的示例包括：

The parser itself is just another program though: Code invoking the parser can catch SyntaxErrors like every other exception (because it is like every other exception). Examples of "invoking the parser" include:

• compile ， exec ， eval


• import 语句


• 模块中的多个功能，例如 ast ， tokenizer ，解析器，等等。

• compile, exec, eval
• import statements
• Several functions in modules like ast, tokenizer, parser, etc.

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