Ok, here is the code I have written so far for the function I am having trouble with... (define (rep-loop) (newline) (display "repl>") (read-token)) (define (read-token) (let ((expr (read-char))) ((cond [(char-whitespace? expr) (read-token1)] [(eq? expr #\() (read-token2)] [(eq? expr #\)) (read-token3)] [(char-alphabetic? expr) (read-token4)] [(char-numeric? expr) (read-token5)] [else (display "Exiting Loop")])))) The cond calls other functions I have written just so I could see it if was reading the output letter by letter... Now I need to make read-token read the whole word if it sees a character and the entire number if it sees a number. Is that getting closer? <div class="gmail_quote">On 9 November 2010 15:28, John Clements <<a href="mailto:clements@brinckerhoff.org">clements@brinckerhoff.org</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> <div class="im"> On Nov 9, 2010, at 12:27 PM, Peter Breitsprecher wrote: > I'd lie but no.. I was just trying to clarify what I was looking for. I gave a the code for one of the functions I had written, and then an example of the input the user is giving below, and then tried to describe in more detail what I needed help with... </div>Well, I'm glad you're not lying :). Can you start by picking a name for the function that you're trying to write? John Clements <div><div></div><div class="h5"> > On 9 November 2010 15:23, Shriram Krishnamurthi <<a href="mailto:sk@cs.brown.edu">sk@cs.brown.edu</a>> wrote: > Hi, > > 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" <<a href="mailto:pkbreits@lakeheadu.ca">pkbreits@lakeheadu.ca</a>> wrote: >> >> As an example, I want have most of the functions for Plus, Minus already written. >> >> 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 <<a href="mailto:clements@brinckerhoff.org">clements@brinckerhoff.org</a>> wrote: >> > >> > >> > On Nov 9, 2010, a... >> >> -- >> Kurt Breitsprecher >> (807) 474-9601 >> <a href="mailto:pkbreits@lakeheadu.ca">pkbreits@lakeheadu.ca</a> >> >> >> _________________________________________________ >> For list-related administrative tasks: >> <a href="http://lists.racket-lang.org/listinfo/users" target="_blank">http://lists.racket-lang.org/listinfo/users</a> > > > > -- > Kurt Breitsprecher > (807) 474-9601 > <a href="mailto:pkbreits@lakeheadu.ca">pkbreits@lakeheadu.ca</a> > </div></div></blockquote></div> -- <div>Kurt Breitsprecher</div> <div>(807) 474-9601</div> <div><a href="mailto:pkbreits@lakeheadu.ca" target="_blank">pkbreits@lakeheadu.ca</a></div>