From: Pisin Bootvong
Subject: Duplicate case warning of symbol in CLISP
Date: Wed, 21 Sep 2005 04:11:29 +0000
Message-ID: <1127275889.819306.279020@o13g2000cwo.googlegroups.com>

CL-USER> (defun foo (s)
	   (case s
	     ('a "a")
	     ('b "b")))
FOO
CL-USER> (compile 'foo)
WARNING in FOO :
Duplicate CASE label QUOTE : (CASE S ('A "a") ('B "b"))
FOO
1
NIL
CL-USER>

Running with CLISP 2.35.
Is that the appropriate warning? Or did I misunderstand anything?

• Re: Duplicate case warning of symbol in CLISP Barry Margolin
• Re: Duplicate case warning of symbol in CLISP Wade Humeniuk

From: Barry Margolin
Subject: Re: Duplicate case warning of symbol in CLISP
Date: Wed, 21 Sep 2005 05:05:41 +0000
Message-ID: <barmar-19A6D3.01054121092005@comcast.dca.giganews.com>

In article <························@o13g2000cwo.googlegroups.com>,
 "Pisin Bootvong" <··········@gmail.com> wrote:

> CL-USER> (defun foo (s)
> 	   (case s
> 	     ('a "a")
> 	     ('b "b")))
> FOO
> CL-USER> (compile 'foo)
> WARNING in FOO :
> Duplicate CASE label QUOTE : (CASE S ('A "a") ('B "b"))
> FOO
> 1
> NIL
> CL-USER>
> 
> Running with CLISP 2.35.
> Is that the appropriate warning? Or did I misunderstand anything?

The notation 'something is actually an abbreviation for the list (quote 
something), so your expression is being treated as:

(case s
  ((quote a) "a")
  ((quote b) "b"))

This means that if the value of S is EQL to QUOTE or A, return "a", if 
it's EQL to QUOTE or B, return "b", otherwise return NIL.  Notice that 
you have QUOTE in both cases.

So you forgot two things: the keys in case clauses are not evaluated (so 
you don't need to quote them), and they can be a list of items.

-- 
Barry Margolin, ······@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

From: Wade Humeniuk
Subject: Re: Duplicate case warning of symbol in CLISP
Date: Wed, 21 Sep 2005 04:35:09 +0000
Message-ID: <1q5Ye.268680$tt5.125734@edtnps90>

Pisin Bootvong wrote:
> CL-USER> (defun foo (s)
> 	   (case s
> 	     ('a "a")
> 	     ('b "b")))
> FOO
> CL-USER> (compile 'foo)
> WARNING in FOO :
> Duplicate CASE label QUOTE : (CASE S ('A "a") ('B "b"))
> FOO
> 1
> NIL
> CL-USER>
> 
> Running with CLISP 2.35.
> Is that the appropriate warning? Or did I misunderstand anything?
> 

It should just be

(defun foo (s)
    (case s
       (a "a")
       (b "b")))

Wade