🚀 go-pugleaf

In article <1992Nov12.141532.16375@jyu.fi>, sakkinen@jyu.fi (Markku Sakkinen) writes:

|> Don't be fooled by words.  Maybe the CLU literature does not much use
|> the word 'reference' (I don't remember), but I cannot see any semantic
|> difference between CLU variables (of non-atomic types) and reference
|> (or pointer) variables in many other languages.  'By sharing' is
|> exactly the same as 'by reference'.

In CLU, x in

	p1 = proc (x: int) ... end p1
and
	p2 = proc (x: string) ... end p2

is passed by sharing.  In the VAX implementation, the p1 has its
argument passed by value, the second by reference (in the grubby
depths).  In the PCLU implementation, both procedure calls pass
a CLUREF structure (by value) which contains the value of an integer
or a pointer to string data.  `By sharing' allows the implementation of
the compiler to choose the mechanism for passing the parameter to
a procedure, the only requirement is that changing the contents of a
mutable argument is reflected in all instances of the argument.

Don't mix implementation strategies with language semantics.

-- 
John Haxby, Definitively Wrong.
Digital				<jch@rdg.dec.com>
Reading, England		<...!uknet!wessex!jch>

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The opinions expressed herein are my own, not my employers.