I just helped someone whose Fedora Core 3 installation was producingthe following error message:

# yum check-updateSetting up repositoriesCannot find a valid baseurl for repo: updates-released

This is a beautiful example of a Unix tendency that people gripeabout: technically correct but completely useless error messages.While yum is correctly complaining that it cannot generate a valid URLfor the 'updates-released' RPM repository, it would be much moreuseful if it told us why, with an error message such as:

Cannot fetch

Exceptions have somewhat of a bad reputation in serious programmingcircles. People feel that they are troublesome for various reasons,including that they are non-local gotos and they make it hard toguarantee that you really are cleaning up after problems. (You canfind posts about this at Joel on Software and in Raymond Chen's blog,among other places.)

I don't know about that, but I do know that exceptions are really goodfor casual programs, which is what I mostly write. Casual programs

Python likes to make programming efficient: that is, to make programsfast and easy to write, and eliminate the tedious drudgery. Prettymuch all dynamically typed languages do, since static typing is a lotof effort (except in languages with a lot of type inference, where itis only some effort).

After writing yesterday's entry ,it's struck me that exceptions are a form of efficientprogramming, because they let you aggregate error checking and errorhandling across a large block of code.

Without exceptions