Pascal and Ada have this I think. I think Eiffel has contracts to enforce that type of thing instead.

Java/Swing: You will be woefully unequipped for the natural cascading property nature of GUI applications; forcing you to jump through giant hoops to get anything to not look awful.

C++/COM: You'll cast IUnknown to ISomethingElse so many times that it will lose meaning.

MSBuild: You will make a typo in a parameter name, but won't find out until two hours into your build when you get an error that could have been caught by a compiler.

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Static typing works for problems that demand rigor, but may be hard to unit test. That includes most larger projects worked on by companies of overworked and slightly disinterested developers.

Dynamic typing works when you can iterate as fast as you can refresh the browser, or when your application is small enough that it is reasonable to full text search the entire thing anytime you refactor anything.

You can build dynamic type systems on top of static ones, but it is ugly. Don't be WPF's DependencyObject system cringe. It is safe, however, to layer dynamic code above static code. Feel free to use a dynamic language for scripting a statically build application.

You can build static type systems on top of dynamic ones, but they will leak. It is also awkward to layer static code above dynamic code. Odds are your code will be dynamic, but more verbose because of the type system getting in your way.

Huh, that spelling problem would give me errors every page.

Python have no warnings for uniquely created/used variables? There is no possibility to demand some declaration of existing variables?

It is quite easy to parse Python(?), so the IDEs should catch this, at least?

  foo = object
  ofo.__call__()

Also, how about this?

  foo = 10
  ...
  if ...
    ofo = 20
  ...
  formula = bah * ( ... foo ... )

2) The opinion of a lot of people on python is that the lack of such (impossible[1]) compiletime tests requires you to replace them with good unit-tests (which should be written anyway). So yes, it is as bad as it looks, but it is recommended to test such things :) Also, there are tools like pychecker and pyflakes, which do sanity-checks which would capture these errors (even though they might be an insane valid python program[1]).

[1] This is impossible, as it is possible to set variables in earlier stack-frames inside a nested call, or I might fiddle around in the locals of an earlier call to get data I want. Certainly, no one would do this (and whoever does such a thing should be stabbed multiple times if this hack persists longer than an hour (hey, I have built such a thing myself to debug a deadlock about resources, it printed the direct caller of the allocation- and deallocation-method, so I could quickly check for unmatched alloc-calls :) )), but it is possible, and thus, the compiler has to assume such things happen.

Do I get this right?

You have to do really hard line testing to avoid simple problems that could be avoided if just variables had to be declared at first use? :-(

But like old C compilers, there is "lint"?

I'm all for nostalgia for old C compilers (except a buggy one, that stole weeks of my life). But that is strange.

I thought Python was all about safety and no problems because of a well designed syntax and coding standards akin to bondage?

Ah well, thanks for information!