written on Tuesday, July 1, 2008
I was reading a thread on ruby-forum.com about Python that said that the whitespace-sensitivity of Python is from hell or something. There are people from every programming language that can rant about Whitespace sensitivity in Python but clearly not Ruby programmers. Why? Because Python doesn't care about Whitespace at all. The only thing that somewhat has to do with whitespace is the indentation that the lexer convers into indent and outdent tokens. But after that, no whitespace any more, the parser doesn't know anything about that.
That however is not true for Ruby! foo does a completely different thing than foo . The first calls foo without argument and calls the  method of the return value with 42 as argument, the latter calls foo with  as Argument which happens to be an Array with one element. But there are more examples.
Take this example:
foo = 23 def bar 42 end puts bar/foo
That prints “1”. That prints “1”.However take this minor modification:
foo = 23 def bar 42 end puts bar /foo
Now this gives you an error that the regular Expression literal is unterminated. That's what I call whitespace sensitivity :)
You're wonderhing why I'm using a method for “bar” and not a locale variable? Because the parser keeps track of all assigned local variables or methods (Not sure what exactly it does) and the syntax ambiguities are resolved that way.