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Comment by jacobparker | Hacker News Reader

And don't forget:

    if(a)
        if(b)
            x;
    else
        y;

This doesn't do what the indentation implies. (http://en.wikipedia.org/wiki/Dangling_else)

Walter Bright (creator of D, etc.) has an article where he discusses his interesting choice to make that grammar form illegal in D. He mentions that after doing this he found a bug in D's runtime library. http://www.drdobbs.com/cpp/dangling-else-yet-again/231602010

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Just see that made me foam at the mouth a little...grr.

We generally don't even like have non-curlied one-liners in our conditionals.

This makes a good point for Python syntax, where you can't by construction end up in situations like that.

Note that any static analyzer that is worth something will warn about this in C/C++. For example, clang will warn with the option -Wdangling-else (implied by -Wall)

True, but the flip side is that in Python automatic indentation cannot possibly work.

Why not? vim indents one more when encountering a colon at the end of a line. It also de-indents when encountering a return or break statement. Of course in all other cases you have to de-indent manually, however, hitting backspace once is not more work than typing a closing curly brace.

What I mean is that you can't tell your editor to indent an arbitrary block of code.

Right, because a block of un-indented python is syntactically incorrect. It would be just like stripping all the brackets out of some C code and asking the editor to add brackets to the resulting mess properly.

As maw points out, that is not a pure win, it is a tradeoff. And it is a tradeoff that I've found to be a really bad one. Being able to run indent over your code and have it automatically formatted is really helpful in large, long term projects where people come and go and weren't effectively forced into using one style.

You can do that with Python code, too.

https://github.com/hhatto/autopep8

Sort of, but not quite. It is quite easy to get situations where code is wrong because of indentation mistakes, copy+paste, etc. All autopep can do is make your wrong code look consistent. Languages with some sort of block delimiter can't get wrong in this manner, so it is safe to munge together random sources with various indenting messes and then just run a tool over them.

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