Re: if-let/if-let*/and-let/..

[Stefan Monnier]

Resending with correct Cc.  Sorry 'bout that and thanks Mark for the
heads up,


        Stefan


Stefan Monnier <address@hidden> writes:

>>> This if/when/and-let/let* business looks pretty messy to me:
>>>
>>> - why do we have and-let* ?  According to its docstring the only case
>>>   when it differs from when-let* is when body is nil, but in that case
>>>   you're better off moving the last binding to the body (and use
>>>   when-let*).
>>
>> The discussion about this was in bug#28254.  The original and-let*
>> version was much more different from `when-let*', but AFAIR Noam vetoed
>> against this version, so they got more similar in the end.
>
> Is it worth keeping this "more similar" result at all?
>
>> The original reason was that we decided that the names without "*" are
>> quite confusing and we wanted to get rid of them in the future.
>
> Is the benefit of slightly reducing confusion (I really find it hard to
> believe the confusion is serious, since the dependencies between the
> different steps would make it rather inconvenient to provide a real
> "parallel-let" semantics) worth the burden of those
> compatibility/obsolescence issues (I'd also mention the confusing
> aspect of having an extra * for a construct that doesn't exist without
> a *, even though traditionally the * is used to mark an "alternative"
> definition, as in list*, mapcar*, ...).
>
> Another question is why aren't when-let and when-let* aliases of
> each other?  Currently we have 5 variants (2 of which are deprecated)
> each with very slightly different semantics.
>
>
>         Stefan
>
>
> PS: I'm also biased against when-let* because I find this * ugly.