Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1997
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1997

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Any uses for SequenceHold ?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg7522] Re: [mg7501] Any uses for SequenceHold ?
  • From: David Withoff <withoff>
  • Date: Tue, 10 Jun 1997 23:17:56 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

> Mma 3.0 has a new Attribute called SequenceHold.
> As far as I can tell this Attribute has no useful application.
> 
> In what way would things fail to work if these function didn't have this 
> Attribute?
> 
> How did ealier versions get by without SequenceHold?
> 
>                Ted Ersek
>                ersek_ted%pax1a at mr.nawcad.navy.mil

Here is Version 3.0:

In[2]:= {x, y, z} /. y -> Sequence[y1, y2, y3]

Out[2]= {x, y1, y2, y3, z}

This works because Rule has the SequenceHold attribute.i
In Version 2.2 this generates an error message and fails.

Dave Withoff
Wolfram Research


  • Prev by Date: combinatorics problem
  • Next by Date: Re: Re: Just another bug in MMA 3.0
  • Previous by thread: Re: Any uses for SequenceHold ?
  • Next by thread: Re: Any uses for SequenceHold ?