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From: awd@dbase.A-T.COM (Alastair Dallas)
Newsgroups: comp.databases
Subject: Re: Is this what's happening ?
Summary: Parameter passing in dBASE
Message-ID: <1991Feb2.070733.7358@dbase.A-T.COM>
Date: 2 Feb 91 07:07:33 GMT
References: <1991Jan31.040806.5135@csun.edu>
Organization: Ashton-Tate, Inc.
Lines: 34


Parameter passing in dBASE is always by reference in the case of
simple memvars and always by value in the case of expressions.

In your example:

	a = "this is a test"
	do icky with a
	? a
	return

procedure icky
parameter foo

	foo = 1
return

You will find that the top-level code prints 1, at least in 
dBASE IV.  To pass parameters by value (generally better
programming practice) you can do as little as enclose them
in parentheses:

	a = "this is a test"
	do icky with (a)
	? a		&& will print "this is a test" no matter what
	return

Internally, dBASE creates a local alias which references the 
parameters which are passed by reference when it processes the
PARAMETERS command.  How you return from the procedure does not
affect the operation.  Of course, if you're using any random
xBASE product ... ;-)

/alastair/