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From: gt4084c@prism.gatech.EDU (SRINIVASAN,K)
Newsgroups: comp.lang.lisp
Subject: Re: macro misbehaviour
Message-ID: <30996@hydra.gatech.EDU>
Date: 10 Jun 91 02:38:59 GMT
References: <16456.285261a2@levels.sait.edu.au>
Organization: Georgia Institute of Technology
Lines: 27

I have a similar problem too.  

I wrote the follwing macro for reading a file and defining classes.
During any single iteration, the three calls to "read" read three
succesive symbols from the file as you would expect.  However, during
successive iterations, the same set of three symbols are read repeatedly.
So, I get the same class defined 4 times instead of defining 4 different
classes.  If I put in 4 explicit calls contained in a progn form instead
of the do-loop, it works fine.  Can somebody please help me fix this 
problem.  Thanks in advance.

Define-Class is a macro calling defclass (written by Marty Hall of AAI Corp.,
and very kindly shared with me). 


(defmacro class-from-file (file-name)
  (with-open-file (input-stream file-name
				:direction :input)
    `(do ((q 4 (- q 1))) ((= q 0) nil)
      (Define-Class ,(read input-stream) ,(read input-stream) .,(read input-stream)))))


-- 
SRINIVASAN,K
School of Textile Engineering   Georgia Tech.
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