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Re: Releasing several Holds simultaneously

  • To: mathgroup at smc.vnet.net
  • Subject: [mg82269] Re: [mg82248] Releasing several Holds simultaneously
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Wed, 17 Oct 2007 03:45:16 -0400 (EDT)
  • References: <200710160727.DAA08807@smc.vnet.net>

On 16 Oct 2007, at 16:27, Andrew Moylan wrote:

> Hold[a := Hold[1]]
>
> How can I release both of these Holds (and thus execute a:=1)
> simultaneously?
>
> ReleaseHold[%] doesn't work; it evaluates a := Hold[1] before the  
> other hold
> is removed.
>
> % /. Hold[x_]:>x does the same thing, because /. only matches once  
> per part.
>
>
  Hold[a := Hold[1]] /. Hold -> Identity

a
1

Andrzej Kozlowski


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