bug#22933: M-x guix-edit fails gracelessly when passed an nonexistent package name

[Alex Kost]

Mathieu Lirzin (2016-03-07 22:58 +0300) wrote:

> address@hidden (Ludovic Courtès) writes:
>
>> diff --git a/emacs/guix-main.scm b/emacs/guix-main.scm
>> index 34da6ac..c5d5d75 100644
>> --- a/emacs/guix-main.scm
>> +++ b/emacs/guix-main.scm
>> @@ -954,10 +954,14 @@ GENERATIONS is a list of generation numbers."
>>  
>>  (define (package-location-string id-or-name)
>>    "Return a location string of a package with ID-OR-NAME."
>> -  (and-let* ((package  (or (package-by-id id-or-name)
>> -                           (first (packages-by-name id-or-name))))
>> -             (location (package-location package)))
>> -    (location->string location)))
>> +  (define package
>> +    (or (package-by-id id-or-name)
>> +        (match (packages-by-name id-or-name)
>> +          (() #f)
>> +          ((first . rest) first))))
>> +
>> +  (and package
>> +       (location->string (package-location package))))
>
> Not related to the bug.  but it feels weird to use internal defines for
> something else than a procedure.

I have the same feeling.

> what about using (not tested):
>
>
>   (and=> (or (package-by-id id-or-name)
>              (match (packages-by-name id-or-name)
>                (()        #f)
>                ((pkg ..1) pkg)))
>          (compose location->string package-location))

I like this variant!

-- 
Alex