Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!motcsd!hpda!hpcuhb!hpcllla!hpclisp!hpclscu!shankar
From: shankar@hpclscu.HP.COM (Shankar Unni)
Newsgroups: comp.lang.pascal
Subject: Re: Re^2: Standard Pascal: Who needs it?
Message-ID: <950029@hpclscu.HP.COM>
Date: 9 Jul 89 22:47:30 GMT
References: <4782@freja.diku.dk>
Organization: Hewlett-Packard Calif. Language Lab
Lines: 37

> Can anyone tell me why get and put are better than read and write?

The I/O model used by Get and Put were very clumsily defined. On a Reset of
a file, the first data item is supposed to be ready for reading (via
file^). In an interactive environment, with input coming in from a
keyboard, this means that the program will hang on a reset, unless the
implementation does some fancy footwork with delayed reads and buffer
validity flags (usually, "f^" is implemented in these cases as:

   if buffer contents are not valid then
      begin
      read in a record;
      end;
   return the contents of the buffer;

and Get is implemented as:

   mark the buffer as having invalid contents.

).

Also, we have to take into account multiple Get's, and so on.

All in all, pretty ugly. "Read" and "Write" provide a much cleaner interface,
including formatting,  conversion of numeric to text data and vice versa, and
so on. It can also be implemented far more cleanly than get or put.

It is pretty clear that the original Pascal was never really designed for
any serious programming. ANSI/ISO Pascal (the original one) was scarcely
better.

The new one seems to be a sort of smorgasbord of everyone's favorite features,
but punts on many important items. Sheesh, it doesn't even have any standard
method of doing conditional compilation, or including files in a compilation
unit.  Back to "cpp" :-(.
----
Shankar ("ex-Pascal compiler drudge") Unni.