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From: fulton@comet.dec.com (Cathy Fulton -- CXO Technical Training)
Newsgroups: comp.lang.pascal
Subject: Re: TP problem
Message-ID: <8711060510.AA12477@decwrl.dec.com>
Date: Fri, 6-Nov-87 01:09:00 EST
Article-I.D.: decwrl.8711060510.AA12477
Posted: Fri Nov  6 01:09:00 1987
Date-Received: Sun, 8-Nov-87 11:38:09 EST
Organization: Digital Equipment Corporation
Lines: 33

jjoshua writes :
 
>	Here's the deal..
> 
>type dirct = (n,s,e,w,ne,se,sw,nw) ;
>var v : dirct ;
> 
>v is a variable with an ennumerated type, right?
> 
>readln(v) ;
> 
>gives an I/O not allowed error. I am using turbo pascal.
>Am I doing something wrong or do I need a REAL compiler?
> 
>Any help SOON would be greatly appreciated.


From "Introduction to PASCAL and Structured Design" by Dale/Orshalick :

"Since user-defined types have meaning only within the program, we cannot
read them in or write them out."  (Note that for Dale/Orshalick, "user-
defined" is an alias for "enumerated.")

It is the exception for a Pascal compiler to provide I/O for enumerated
types.  It is not part of the language definition.  One semester I did a
project in Pascal on a SUN running Unix, and I was really suprised when I
was able to directly write out enumerated types - I thought it was pretty
neat.  But, the compiler did warn me that that was a "non-standard feature;"
this is further evidence that such a capability is exceptional.

- Cathy

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