Re: Default mutable parameters in functions

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From	Dennis Lee Bieber <wlfraed@ix.netcom.com>
Subject	Re: Default mutable parameters in functions
Date	Fri, 04 Apr 2014 19:23:22 -0400
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On Fri, 04 Apr 2014 10:00:25 -0400, random832@fastmail.us declaimed the
following:

>
>I can't imagine a language that would work that way. For one, it would
>also imply that passing a value would change the default for future
>calls even for non-mutable types.

	Some early FORTRAN compilers purportedly had problems with, for
example:

	X = 1
	call mutant(1)
	Y = 1
	
where

	subroutine mutant(y)

	y = y + 1
	return

meant that Y now held the value of 2 -- that is, literals were stored in
mutable memory, and since FORTRAN passes by reference, the address of the
literal is passed, and the assignment changed the "constant".
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

Thread

Default mutable parameters in functions fbicknel@gmail.com - 2014-04-03 11:49 -0700
  Re: Default mutable parameters in functions Ian Kelly <ian.g.kelly@gmail.com> - 2014-04-03 15:32 -0600
  Re: Default mutable parameters in functions Ethan Furman <ethan@stoneleaf.us> - 2014-04-03 14:44 -0700
  Re: Default mutable parameters in functions Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-04-03 20:27 -0400
  Re: Default mutable parameters in functions Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-04-04 01:38 +0100
  Re: Default mutable parameters in functions random832@fastmail.us - 2014-04-04 10:00 -0400
    Re: Default mutable parameters in functions Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-04-04 14:34 +0000
      Re: Default mutable parameters in functions Chris Angelico <rosuav@gmail.com> - 2014-04-05 09:47 +1100
  Re: Default mutable parameters in functions Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2014-04-04 19:23 -0400
    Re: Default mutable parameters in functions Roy Smith <roy@panix.com> - 2014-04-04 19:38 -0400
  Re: Default mutable parameters in functions Dave Angel <davea@davea.name> - 2014-04-04 22:21 -0400

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