Readline read_history and write_history addition
simonmarhaskell at gmail.com
Tue Feb 5 04:38:14 EST 2008
Judah Jacobson wrote:
> On Mon, Feb 4, 2008 at 6:06 AM, Yitzchak Gale <gale at sefer.org> wrote:
>> Simon Marlow wrote:
>> > However, I do agree that exceptions should generally be used for
>> > exceptional conditions, rather than for general control-flow. This is an
>> > example of a *good* reason to avoid an exception: because to use an
>> > exception for a non-exceptional condition is poor style.
>> That is also my opinion. Some people have disagreed.
>> So this should be the focus of the decision then.
> I also agree that exceptions should only be used for exceptional
> conditions; but I do think that this is one of those situations. I'll
> try to explain why below. (Thanks, Yitzchak, for forking off the
> thread about fixing limitations of MonadIO.)
> I assume that the following conditions are already considered
> exceptional (I haven't ever heard anyone complain that they throw an
> - readFile : read a nonexistent file
> - writeFile : write to a file in a nonexistent directory
> - getEnv: retrieve an unset environmental variable
FWIW, this was hotly debated at the time, and I do believe we made the
wrong decision w.r.t. getEnv, mainly because I always end up writing "try $
getEnv", or I forget the try and have to fix the bug later.
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