Timeline for UpValues, TagSet and UpSet, what's the difference, when should you use them?
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 11, 2019 at 15:47 | history | edited | gwr | CC BY-SA 4.0 | improved grammar in title |
| Apr 13, 2017 at 12:55 | history | edited | CommunityBot | replaced http://mathematica.stackexchange.com/ with https://mathematica.stackexchange.com/ | |
| Sep 1, 2016 at 23:02 | comment | added | Leonid Shifrin | @Mr.Wizard Apparently, things are worse, and the change happened at the gravatar.com, not SE. They changed the algorithm they use to compute the image. Luckily I had some old .nb file with the old image, although the resolution is quite low. I don't have the time right now to dig deeper and fully reconstruct the avatar programmatically, so I guess that will do for the time being. | |
| Sep 1, 2016 at 22:52 | comment | added | Leonid Shifrin | @Mr.Wizard Re: avatar - good idea. Will do that. | |
| Sep 1, 2016 at 22:52 | comment | added | Leonid Shifrin | @Mr.Wizard There certainly is a difference.When you execute e.g. ClearAll[a, b, c, d]; f[a, b, c] ^= d;, all of the a,b,c get UpValues, whereas when you execute ClearAll[a, b, c, d]; a /: f[a, b, c] = d;, only a does. With more complicated patterns involving blanks, it may matter. Generally, you want to be as precise as possible, to not produce extra global rules besides those you need, because they may fire in unforeseen situations. Actually, we pay for locality of overloading based on UpValues with making it harder to see why a given rule fired. No reason to make it harder still. | |
| Sep 1, 2016 at 22:20 | comment | added | Mr.Wizard | @Leonid (1) Is there a case where than actually results in a difference in evaluation? I still have the nagging feeling I have seen one but I can't seem to recreate it. (2) That's too bad, as I really quite liked your old one. Did you keep a copy of it? Maybe set that profile picture manually if you agree with me. | |
| Sep 1, 2016 at 12:50 | comment | added | Leonid Shifrin | @Mr.Wizard Re: UpSet vs TagSet - the only practical difference I am aware of is that TagSet is more precise, and will only add an UpValue to a symbol you specify, while UpSet will add UpValues for all symbols at the first level in the l.h.s. of the rule. Re: email change - the funny this is, I didn't change it! Apparently, SE changed the algorithm they use to compute at least some gravatars. I've noticed it and some other users seem to have been affected by it as well (although not all, it seems). | |
| Sep 1, 2016 at 12:13 | history | edited | Murta | CC BY-SA 3.0 | added 1 character in body |
| Sep 1, 2016 at 11:13 | comment | added | Mr.Wizard | @Leonid Would you please see the comments under my answer? I am struggling to think of a case where TagSet versus UpSet makes a practical difference, yet I still think I have seen one? By the way I see you have changed your email address and therefore your Gravatar. It will be hard to get used to seeing a different icon beside your name. | |
| Feb 27, 2013 at 11:14 | comment | added | Murta | No! Just forgot. Tks! | |
| Feb 27, 2013 at 11:14 | vote | accept | Murta | ||
| Feb 27, 2013 at 8:31 | comment | added | Mr.Wizard | Murta, I see that you did not Accept my answer. Is there something I can do to make it more satisfactory? | |
| Jan 26, 2013 at 0:52 | comment | added | Murta | Tks @LeonidShifrin, It was very helpfull. | |
| Jan 25, 2013 at 10:11 | comment | added | Leonid Shifrin | In addition to the answer of @Mr.Wizard, I discussed exactly this issue in this answer (last subsection), where it is put in a wider context of UpValues in general. | |
| Jan 25, 2013 at 4:47 | history | tweeted | twitter.com/#!/StackMma/status/294667779557187584 | ||
| Jan 25, 2013 at 3:24 | answer | added | Mr.Wizard | timeline score: 25 | |
| Jan 25, 2013 at 2:50 | history | asked | Murta | CC BY-SA 3.0 |