Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!ubc-cs!!tacitus!clh
From: clh@tacitus.tfic.bc.ca (Chris Hermansen)
Newsgroups: comp.lang.pascal
Subject: Another simple question (BSI/ISO Pascal)
Message-ID: <115@tacitus.tfic.bc.ca>
Date: 17 Oct 89 16:01:58 GMT
References: <115@m1.cs.man.ac.uk>
Reply-To: clh@tfic.bc.ca (Chris Hermansen)
Organization: Timberline Forest Inventory Consultants, Vancouver BC
Lines: 38

Perhaps one simple question deserves another...

Does anyone care to offer an explanation/excuse as to why most Pascal
implementors have totally screwed up the I/O?  For example, adding the
so-called `interactive' file type, file pointers that become undefined
when there's actually something in the file, etc etc?

The last I recall, a generally acceptable solution to implementing
Pascal I/O was using `lazy I/O', as in:
	- reset(f): open the file and set flag indicating f^ needs filling
	- get(f): set flag indicating f^ needs filling
	- eof(f), eoln(f): fill f^ if necessary, reset flag, and check the condition
	- references to f^: fill f^ if necessary, reset flag, and do whatever
So anyway, the beauty of this was supposed to be that segments of code like
	var
		c1, c2: char;
		f: text;
		...
	reset (f);
	write ('Type a character ');
	readln(f,c1);
	write ('Type another character ');
	readln(f,c2);
	...
would `work as expected', without any hidden gotchas introduced by an
interactive file type.

I *think* this is the way Sun Pascal does it; T***o certainly doesn't, nor
did Microsoft at the point I tried it (several years ago), nor did the
P-system, nor the 370 Pascal compiler that UBC made while I was a student
there.

Any thoughts?

Chris Hermansen                         Timberline Forest Inventory Consultants
Voice: 1 604 733 0731                   302 - 958 West 8th Avenue
FAX:   1 604 733 0634                   Vancouver B.C. CANADA
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