Re: if-let and when-let: parallel or sequential

[Bozhidar Batsov <bozhidar.batsov@gmail.com>]

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On August 10, 2014 at 6:23:25 PM, Stefan Monnier (monnier@iro.umontreal.ca) wrote:
> I noticed that the new `if-let' and `when-let' in trunk's subr-x create  
> their bindings sequentially (like `let*' rather than `let'). Would there  
> be any interest in renaming these to `if-let*' and `when-let*', and  
> adding parallel-binding versions under the current names?  

I have a hard time imagining a situation where the "parallel" version  
would be useful.  


Stefan  


if-let and when-let don’t make much sense with more than one binding form. Other lisps (like Clojure) would raise
an exception if you try to bind more than a single form.

;; good
(if-let ((x (something)))
    …)

;; error
(if-let ((x (something))
           (y (something-else)))
    …)

I’d suggest we do the same. 

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