Re: [Caml-list] tail rec

[Brian Hurt <bhurt@janestcapital.com>]

Robert Fischer wrote:

>
>> I'm repeating my suggestion: extend the typing annotation (produced 
>> by -dtypes) to flag every tail recursive call, and have the emacs 
>> mode and ocamlbrowser display every tail call particularily (e.g. in 
>> a different color or font).
>>
>> This don't require any additional language construct.
>>   
>
> Oh, then we're cool.  :-D
>
>> Also, tail recursion is IMHO a beginner's puzzle. I'm pretty sure 
>> every experimented Ocaml programmer does know inside his code what 
>> are his tail recursive calls.
>>   
>
> If you asked me to point them out, I could.  If you asked me if a 
> given function is tail recursive, I could tell you.  I also use tail 
> recursive calls unintentionally, and (while I realize now that you're 
> not proposing this) I was concerned my code suddenly wouldn't compile 
> because I didn't happen to tag a tail recursion.

Most of the time you don't care wether a particular call is a tail call 
or not.

I will comment: in my experience, new programmers make simple mistakes 
for simple reasons, while experienced programmers make simple mistakes 
for complicated reasons.

Actually, I can see uses for this, even for experienced, knowlegable 
programmers.  For example, I can imagine scenarios where, during 
maintainance, a try/catch block is introduced, making a tail call that 
needed to be a tail call into a non-tail call.  Opps.  I don't think 
this happens all that often, so it's not that valuable to experienced 
programmers, but every little bit of correctness helps.

Brian