Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-ses!hpcuhb!hpindda!tribby
From: tribby@hpindda.HP.COM (David Tribby)
Newsgroups: comp.sys.apple
Subject: Re: P-Systems (was Re: Computer languages on the various Apple Corp
Message-ID: <6230031@hpindda.HP.COM>
Date: 31 May 89 16:46:43 GMT
References: <8905271756.AA29116@crash.cts.com>
Organization: HP Information Networks Group/Cupertino CA
Lines: 24

dlyons@Apple.COM (David Lyons) writes...
> 
> BTW, I don't object to "lumping" P-code systems in with interpreted BASICs.
>        ...               And there's no reason a P-code Pascal couldn't do
> slow searches for variables if it really wanted to.
> 
>  --Dave Lyons, Apple Computer, Inc.          |   DAL Systems

I hate to disagree with one of my favorite Apple experts, but the big
difference between interpreted BASIC and the P-system is the amount of
"digesting" done before execution of the program. With BASIC, the exact
structure of the source program must be maintained because the user
may modify it. Very little is done, except tokenization of key words.
With P-code Pascal, the source code is actually compiled. During execution
there is no need to search for variables since they will be at fixed
locations. Yes, the P-code must be interpreted, but it is much closer to 
machine code than BASIC tokens.

The P-code system spends a lot of time compiling and linking so that it can be 
more efficient in execution than a purely interpreted language.

--Dave Tribby
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        ARPA: tribby%hpda@hplabs.HP.COM   UUCP: hplabs!hpda!tribby