Hello everyone on the forum. This is my first post here.

One of the most annoying things about the prime is that there is no undo function.
Does anybody have an idea how this could be fixed with a user programmable key shortcut? I have no idea how to implement the function. But I also have no experience with HP calcs. So I hope one of the HP gurus in the forum can find a solution.

I really don't get how they could "forget" such an essential feature. What was there intended target group for the calculator? Chuck Norris and God? People make errors! And its really annoying if you type a big equation and then press the wrong button at the wrong time and everything is deleted. Or tap the wrong menu item which messes up the input line with a command that you don't want and then one has to delete every single character on the input line individually instead of just hitting "undo". Come on HP, seriously?

- Stefan

+1

One error I've made more often than once is hitting the key just below the OK softkey which unfortunately is ESC. :(

Undo would have helped a lot.

+1

I hit ESC ALL THE TIME.

There should also be a mode to put the soft keys on the top or side
of the screen so that people that know how to use HP calculators
don't get confused by what it means to use an HP calculator.

A use of "strings" on the armfir.elf file from the Firmware.zip archive reveals strings like "Undo", "Redo" and "Undo history". So *maybe* an undo function is implemented but not user accessible up to now. But this could also just be from the Geometry App which has an undo function mapped to numeric key "4".

But I don't give up the hope that a future update will include this feature. I think the demand is definitely there.

- Stefan

The question regarding UNDO always becomes one of "to what extent and what limits?"

Do you only undo clearing of text? What about individual letter typing? What about if the user does M1:=[2] and overwrites M2, then does an UNDO? What if the user resets the app catalog? What if the user runs a user program which changes a large number of variables?

In each of these cases and thousands more, decisions have to be made regarding if, and what to do in those cases. That has to be balanced against memory, speed, expectations, and so on.

UNDO really is not a simple thing.

TW

I vote for unlimited undo in the editor and on the command line but not for any command already submitted. Destructive commands should be protected by a confirmation, at least if called from the keyboard.

Quote:

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Do you only undo clearing of text? What about individual letter typing? What about if the user does M1:=[2] and overwrites M2, then does an UNDO? What if the user resets the app catalog? What if the user runs a user program which changes a large number of variables?

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For a start, take a look at TI Nspire. I don't state it's *the* way to do it, but it would be at least a good start. They seemed to orient their undo system on the average PC undo function (it's even mapped to Ctrl+Z, Redo is mapped to Ctrl+Y). In regard to the questions above that means:

1. No individual character typing undo. "Undo" undoes complete "words".
   
2. Variable assignments are not undone
   
3. Changes that happen in Dialog boxes can not be undone
   

Some comments to each point:

1. I think undoing individual characters is not necessary. They can be erased and replaced more easily via backspace/delete et cetera.
   
2. If I accidently reassign a variable I usually can find the correct assignment in the history, tap it to copy it to the input line and then re-execute it.
   
3. Dialog boxes usally do not contain big equations or other stuff that could not be recoverd with a few keys. Undo would maybe still be nice, but not necessary IMO.
   

Quote:

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UNDO really is not a simple thing.

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Oh, and of course there should also be a "Redo" function, to undo the undo ;)

- Stefan

I diagree about the confirmation message (at least for very common destructive commands). I don't always want to tap "Yes" when I delete the input line.

Assuming that there will be a undo function at some point in the future (whatever it will look like), then only things that can not be undone by that function and which are not trivial to recover should need a confirmation message.

Hi everyone !

The Prime lacks of auto repeat key feature Too !
UNDO/REDO plus AUTO REPEAT KEY features for the next firmware update !

PLEASE SAVE THE PRIME's KEYBOARD ! (And users)!

Dam.