Hi Nicolas, After reviewing my code, I don't think it will suffice for your needs. As I said, mine was more character/word based which would be overkill on a large document. More suited to a small text field where lot's of changes to characters or words will happen. That's not the same as with something like, say, a word-processor.
The likely method for a WP-like unlimited Un/Re-do is to work with chunks. It's going to be a major memory-whore for large text but the most practical, easy way. You need to setup a global array (gFldTxtA) to store the entire field for each state you want to return to, index-based (1 to n). You'll also need a script local (sFldTxtCurrIndex) to store your current array index number. Each time a key is pressed update gFldTxtA[sFldTxtCurrIndex] with the field content (all of it). (Note: if it gets really large you may have to just add a char at a time to it). Any time the returnKey, deleteKey, arrowKey, pasteKey, cutKey, copyKey, backspaceKey or tabKey is pressed you want to catch this and add 1 to your sFldTxtCurrIndex and store your new field content into that for safe-keeping. Now your undo and redo buttons shift through the array updating the sFldTxtCurrIndex as it goes. Once the user starts typing or adding more text again, all indices of gFldTxtA after the current index need to be wiped (in keeping with common practice) and the current index set. If you want them to undo redo's as well you will need another script local var to keep track of these - but will get brain-twistingly complex. Undo/redo truly is one of the biggest implementation, testing and maintenance headaches for any sized application. It's no wonder it took until iOS3 for it to be added to iPhones (badly) along with copy/paste (which can be equally as distressing when you realise the shear mass of 'types' there are). It's easily underestimated and taken for granted. I hope this helps in some way. All the best. Sean Cole Pi Digital On Tue, 9 Jul 2019 at 10:24, Pi Digital via use-livecode < use-livecode@lists.runrev.com> wrote: > Hi Nicolas > > It becomes quite the memory hoarder as the document goes on (as you can > imagine) but I created one that is basically an indexed svc-like array. It > can be char or word based. > > I also created (although it wouldn’t suit your purpose) a very complex > undo/redo for a number of prototype game show apps that covered anything > that happened. It twists your brain working out the infinite possibilities > but is doable. It often just takes a bit of research and planning - > especially if you are breaking new ground. > > I’ll post up a simplified script in a bit. > > Sean Cole > Pi Digital Prod Ltd > > > On 9 Jul 2019, at 04:05, Nicolas Cueto via use-livecode < > use-livecode@lists.runrev.com> wrote: > > > > Good day eh. > > > > To quote a post from "User Experience Stack Exchange > > <https://ux.stackexchange.com/questions/12629/undo-history-why-limit-it > >": > > > > "<bold> undo/redo is one of the biggest implementation, testing and > > maintenance headaches </bold> in any significantly sized application" > > > > And yet I ask... > > > > Would someone care to volunteer a redo/undo script that works on text in > a > > text-field object? ... especially a script that provides (almost) full > undo > > history? > > > > (Note: Just changes to text. Not to LC objects themselves.) > > > > Ta. > > -- > > Nicolas Cueto > > _______________________________________________ > > use-livecode mailing list > > use-livecode@lists.runrev.com > > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > > http://lists.runrev.com/mailman/listinfo/use-livecode > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
