Why static typed languages are sometimes better.
donn at u.washington.edu
Fri Jul 2 00:15:46 CEST 2004
In article <roy-C894A6.17435601072004 at reader2.panix.com>,
Roy Smith <roy at panix.com> wrote:
> I just had an interesting little surprise. I've got a method that takes
> a string as an argument. I wanted to change it to take either a string
> or a tuple of strings, so I did my usual "test first" thing.
> I changed the unit test I already had from calling it with a string to
> calling it with tuple of two strings. I then ran the test, expecting it
> to fail. The next step would be to go write the code to make the test
> Amazingly, the test passed (that means I'm done, right?). Well, it took
> me a moment to realize that the only thing I ever do with the argument
> in the current version is use it as a dictionary key. Since a tuple of
> two strings is a valid key, so the test passed just fine. Sometimes the
> language is just too forgiving :-)
Static typing might also have the salutory effect of
helping you decide not to do this in the first place.
You'd change the function parameter type from String
to [String], and recompile. The compiler would tell
you about every place where the function is called
with a String parameter, and you'd go and change them
from 'xyz "Hello"' to 'xyz ["Hello"]'. Takes 10 minutes
and leaves you with simpler, easier to understand code.
Donn Cave, donn at u.washington.edu
More information about the Python-list