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Path: utzoo!utcsrgv!dave
From: dave@utcsrgv.UUCP (Dave Sherman)
Newsgroups: net.std
Subject: Re: How to store video attributes in a text file - VT-100 format OK?
Message-ID: <4156@utcsrgv.UUCP>
Date: Fri, 4-May-84 14:50:21 EDT
Article-I.D.: utcsrgv.4156
Posted: Fri May  4 14:50:21 1984
Date-Received: Fri, 4-May-84 15:26:27 EDT
References: <1239@brl-vgr.ARPA>, <422@denelcor.UUCP>
Organization: The Law Society of Upper Canada, Toronto
Lines: 58

~|  From: apratt@iuvax.UUCP
~|  It makes the code look a little worse, but in a C program, the "accepted"
~|  modular-programming method would be:
~|  
~|  #define ON 1
~|  #define OFF 0
~|  
~|  	printf("This is ");
~|  	highlight(ON);
~|  	underline(ON);
~|  	printf("very");
~|  	highlight(OFF);
~|  	underline(OFF);
~|  	printf("important\n");
~|  

I know. If I only did the highlighting occasionally, that would be OK.
Problem is, I have some quizzes which can only be done in C (they use
structures and logic which are beyond the scope of any file-driven CAI
language I have access to). And in these quizzes I often use underlining
and the like.

~|  That way, the functions could take care of sending the apropriate code.
~|  Redefining putc will *not* work if you use printf, unless you redefine printf
~|  as well. This is because the library version of printf would not use your
~|  new and improved putc as a filter/translator/interpreter.

You're right, of course. I forgot to mention in the original article
that I also recompiled _strout with an #undef putc, so that it would
link in my putc function.

~|  
~|  In text files, however, the ANSI standard is as good as any, but a little
~|  verbose; writing an interpreter for it (to include cursor motion, screen
~|  clearing, etc.) is not trivial.

That's why I asked on the net - and received several!

~|				Also, you should keep in mind that not a lot
~|  of terminals have such features as double height/double width lines.

Lots of terminals can't do highlighting either. That's fine - the
terminal will do what it can.

~|  Of course, these files would have to be run through a filter which interprets
~|  the embedded ANSI codes and sends the appropriate termcap-supported codes.
~|  This all is assuming, of course, that you want portability from UNIX to UNIX
~|  as well as terminal to terminal.

That's the whole idea. In my CAI system, text files are copied to the
terminal with while((c=getc(infile)!=EOF)putchar(c);, so the same
redefinition of putc that works for printf works for the text files.


Dave Sherman
-- 
 dave at Toronto (CSnet)
 {allegra,cornell,decvax,ihnp4,linus,utzoo}!utcsrgv!dave