[racket] Quoted expressions in #lang racket

From: Racket Noob (racketnoob at hotmail.com)
Date: Sun Sep 18 13:20:29 EDT 2011


 You can't compute (car (1 2 3)) because before car even begin, it's parameter, list (1 2 3) must be evaluated, but 1 is not a procedure name. It is different than in (quote (1 2 3)) where such evaluation doesn't take place. > Date: Sun, 18 Sep 2011 12:05:20 -0500
> From: grettke at acm.org
> To: matthias at ccs.neu.edu
> CC: eli at barzilay.org; sk at cs.brown.edu; users at racket-lang.org
> Subject: Re: [racket] Quoted expressions in #lang racket
> 
> On Sun, Sep 18, 2011 at 11:41 AM, Matthias Felleisen
> <matthias at ccs.neu.edu> wrote:
> >
> > Mr Noob: if (1 2 3) is a value, why can't I compute (car (1 2 3)). 4 is a value and I can compute (+ 4 3). #t is a value and I can compute (not #t). Why do you insist that I cannot compute with (1 2 3) if it is a value?
> 
> Maybe RacketNoob can start by doing this:
> 
> "In the bottom left hand of the screen in DrRacket click the "Choose
> Language" dropdown, "Use the language declared in source" should be
> selected on the left.
> 
> On the right you can choose the "Output Syntax". If you change it to
> "write" then it will look how you want."
> 
> And then we can point him at some good things to read that will help
> him make sense of all the good points and advice everyone has shared.
> 
> Perhaps: Racket reader documentation, quote documentation, Scheme
> standard? That is how I learned. I loved this passage from the R6RS
> spec:
> 
> ``It is important to distinguish between the mathematical numbers, the
> Scheme objects that attempt to model them, the machine representations
> used to implement the numbers, and notations used to write numbers.''
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