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The History of the "Undo" Function?
TheLocustNMI asks: "So, earlier today as I was typing out some magnum opus of a stored procedure, I highlighted to copy it, and hit SPACE instead of Ctrl-C. Without thinking, I hit Ctrl-Z to 'undo' my folly. Pausing a moment to reflect, I realized that I own countless hours of thanks to whomever came up with the "undo" button. In short -- my question is this -- where did it come from? What are the earliest implementations of the 'undo'? (a quick googling returns this page, a cornucopia of undo and history related treatises)"
A better place to ask this question would be alt.folklore.computers on usenet.
And the second "undo" button was the penknife, which you could use to scrape off the white-out that you applied by accident.
"Can of worms? The can is open... the worms are everywhere."
.. or do you find yourself saying "Control-Z" in your mind whenever you find yourself making mistakes while not sitting in front of a computer..spilling a glass of milk...etc
That's right people ... Apple did it first (at least in a consumer machine).
The original Macintosh had "undo" functionality in its applications, right from the start.
The Apple IIGS also had "undo" functionality.
There may have been one or two individual applications before it (I don't know) but the Mac made "undo" ubiquitous.
Yes, MIT's Lincoln Reckoner had multiple-level undo/redo in 1968. That used a screen editor, so it would be the kind of undo you are talking about, however it was probably inspired by IBM's APL line-based workspace editor.
APL programmers had multiple-level undo/redo on their selectric typewriters around 1965. Each interaction was numbered, and you could select the number of the last interaction you wanted to keep. This would reset the entire workspace so that all variables, your program image, and options would be restored. This worked by saving the workspace each time a command completed, and was also useful for restoring sessions after interrupted connections.
Single-level undo appeared much earlier -- the first IBM teletype line editors in the late 1950s had single-level undo.
Here's what one well known Academy Award winning 3D package does. Every command is an object. When you execute a command that object is stored in a 'history'. The command has two methods, a do() method and an undo() method. As long is the object remains alive it can undo or redo the associated operation.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
I remember a rudimentary CAD program for the Apple ][+, circa 1982 or 1983. I wish I could remember the name...
I personally first encountered "Undo" on the Mac in 1984. But this CAD program had a function... they didn't call it "commit." I don't remember the exact language they DID use.
The idea was that you never had to worry about making mistakes, because every action you took was tentative, and would be shown to you as a preview before taking effect.
So you'd give a command to draw a line, you'd see the line onscreen, and you could either accept it (in which case it became part of the drawing) or reject it (in which case it disappeared).
The weird thing about all this is that logically, it is exactly equivalent to an "undo" function.
And the even weirder thing is that while an "undo" function feels empowering and liberating... when the exact same function was presented as "tentative action, preview, accept/reject" it felt clumsy and laborious.
To me, anyway.
"How to Do Nothing," kids activities, back in print!