From: Randall Randall
Subject: Re: First element of a quoted list
Date: Thu, 11 Nov 2004 15:46:02 +0000
Message-ID: <4193896b$1_2@alt.athenanews.com>

gewoon.iemand wrote:
> Hi
> 
> I'm implementing a LISP interpreter in JAVA. I have made a structure
[...]
> However, I'm running into a problem when I parse quoted lists. I could
> enter '(aVariable 1 2 3) or '(aFunction 1 2 3). When it gets parsed,
> the parser cannot know whether its a variable or a functor. I could
> also enter '(1 2 3 4), and the first element is neither.
> 
> How should I deal with this? Is my implementation wrong and should I
> make the determination of whether to treat the first element as a
> symbol, functor or constant at run time, when a list is evaluated?

For this thing, you should translate '(1 2 3) into (quote 1 2 3).
However, it seems like you're missing the difference between
functions and macros entirely, given the question I snipped below
about SETQ.  Are you writing a Lisp without macros?

--
Randall Randall <·······@randallsquared.com>

• Re: First element of a quoted list Geoffrey Summerhayes
  • Re: First element of a quoted list Randall Randall
• Re: First element of a quoted list Barry Margolin

From: Geoffrey Summerhayes
Subject: Re: First element of a quoted list
Date: Thu, 11 Nov 2004 17:53:00 +0000
Message-ID: <6GNkd.29918$Z7.966399@news20.bellglobal.com>

"Randall Randall" <·······@randallsquared.com> wrote in message 
·················@alt.athenanews.com...
>
> For this thing, you should translate '(1 2 3) into (quote 1 2 3).

Not quite,

'(a b c) => (quote (a b c))
'a       => (quote a)
'(a)     -> (quote (a))

--
Geoff 

From: Randall Randall
Subject: Re: First element of a quoted list
Date: Fri, 12 Nov 2004 05:02:24 +0000
Message-ID: <41944412$1_5@alt.athenanews.com>

Geoffrey Summerhayes wrote:
> "Randall Randall" <·······@randallsquared.com> wrote in message 
> ·················@alt.athenanews.com...
> 
>>For this thing, you should translate '(1 2 3) into (quote 1 2 3).
> 
> 
> Not quite,
> 
> '(a b c) => (quote (a b c))
> 'a       => (quote a)
> '(a)     -> (quote (a))
> 


Quite right.  I plead sleepiness. :)

--
Randall Randall

From: Barry Margolin
Subject: Re: First element of a quoted list
Date: Fri, 12 Nov 2004 00:10:42 +0000
Message-ID: <barmar-0AACC7.19104211112004@comcast.dca.giganews.com>

In article <···························@posting.google.com>,
 ·············@gmail.com (gewoon.iemand) wrote:

> > For this thing, you should translate '(1 2 3) into (quote 1 2 3).
> > However, it seems like you're missing the difference between
> > functions and macros entirely, given the question I snipped below
> > about SETQ.  Are you writing a Lisp without macros?
> 
> You hit the nail right on the head, thanks. I hadn't really looked
> into macros and thougt of getting some basic functions working before
> doing anything fancy. Turns out macros are really important and I need
> a bit of investigating and change my implementation.

You also need to handle special operators, which are analogous to the 
basic syntactic forms in other programming languages.

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