[racket] Simple Scheme Interpreter written in Drracket

From: Shriram Krishnamurthi (sk at cs.brown.edu)
Date: Tue Nov 9 15:23:53 EST 2010


That would not be considered an "example" for at least two reasons. Do you
see why?

On Nov 9, 2010 12:17 PM, "Peter Breitsprecher" <pkbreits at lakeheadu.ca>

As an example, I want have most of the functions for Plus, Minus already

Here is the code for it.

(define (plus num1 num2)
(+ num1 num2))

That is childs stuff...  Here is where I am having the problem, and please
keep in mind I am new to DrRacket...

If my program accepts input such as
(plus 13 5)

I need to parse it so that I know what it is asking for.  If It is a left
parent, then I need to move on, if it is a right parent, move on to the next
character, once i get to the next character I can see it is an alphanumeric
character, but then I need to somehow read the whole word, so that I can
store that value in a variable so that I can read the next number.  If the
numbers are single digits, it is easy, because they are only one charater
each and read-char works perfect, but I need something like a read-word, or
read-number and I can't seem to figure out how to do it.

So really I need to know how do I read the words when there are characters
present, and read the whole numbers when there is a number present.

On 9 November 2010 15:00, John Clements <clements at brinckerhoff.org> wrote:
> On Nov 9, 2010, a...

Kurt Breitsprecher
(807) 474-9601
pkbreits at lakeheadu.ca

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