assert statement

[Akuli]

There is currently no good way to do assert(). C's assert() is a macro, not a function, so you can't just declare it and use it in Jou.

You can define your own assert() function but it has some disadvantages:

• The compiler won't understand that code after assert(False) is unreachable.
• You can't get line number and file name appear in error message

I think the real solution is a built-in assert statement, similar to Python and Java.