Re: Problem in loading packages in Mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg70689] Re: Problem in loading packages in Mathematica
- From: Bill Rowe <readnewsciv at sbcglobal.net>
- Date: Mon, 23 Oct 2006 02:50:27 -0400 (EDT)
On 10/22/06 at 1:19 AM, hpr at together.net (Helen Read) wrote: >I believe that in newer versions of Mathematica (certainly 5.x, >maybe earlier), loading a package with << does exactly the same >thing as Needs, and there is no problem with loading twice the way >there used to be. This is not correct. Whether there is a problem or not with loading a package twice depends on how the package is written. To demonstrate this save the following code as testPkg.m BeginPackage["testPkg`"] userFunction::usage="usage message" Begin["`Private`"] userFunction[]:="user function results" End[] Protect[userFunction] EndPackage[] You will find that if you attempt to load this package a twice using Get or <<, you will get an error message. But you will not get an error message with Needs. Now I can prevent the error message using Get by deleting the line with Protect or adding Unprotect[userFunction] after BeginPackage statement. >I have had problems getting Needs to work on some >systems, and have gone over completely to << with no problems >whatsoever. I can believe this. A well written package will allow the user to load it twice in whatever way the user chooses to load the package. -- To reply via email subtract one hundred and four