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From: Patricia Ferreira <pferreira@example.com>
Newsgroups: pt.comp.programacao
Subject: Re: o resto =?utf-8?Q?=C3=A9?= Python
Date: Fri, 08 Mar 2024 18:48:55 -0300
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Patricia Ferreira <pferreira@example.com> writes:

> Preciso de um procedimento que testa (sem sequência) se dois valors u, s
> são nulos.  Se forem, retorne NIL.  Se não for, obtenha uns valores.
> Eis como fazer:
>
> (defun last-time-seen (username)
>   (let ((u (get-account username)))
>     (and u (let ((s (account-seen u)))
>              (and s (universal-to-human s))))))
>
> Moleza.  Mas eis como um Lisper realmente faz:
>
> (defun last-time-seen (username)
>   (when-let* ((u (get-account username))
>               (s (account-seen u))
>     (universal-to-human s)))
>
> When-let*.  Isso é linguagem de /programação/.  O resto é Python.

Mas, pra ser justo, isso não é Common Lisp.  Isso é Alexandria.

  Alexandria: https://alexandria.common-lisp.dev/

  --8<---------------cut here---------------start------------->8---
  Alexandria is a project and a library.

  As a project Alexandria's goal is to reduce duplication of effort and
  improve portability of Common Lisp code according to its own
  idiosyncratic and rather conservative aesthetic. What this actually
  means is open to debate, but each project member has a veto on all
  project activities, so a degree of conservativism is inevitable.
  --8<---------------cut here---------------end--------------->8---