Editing Sinhala and Similar Scripts

J. Leslie Turriff jlturriff at centurylink.net
Wed Mar 19 23:17:24 CDT 2014

	Perhaps it might be useful to be able to distinguish between an "editing 
mode" and a "composition mode":  editing mode would be active when a document 
is first loaded into the editor, when the editor has no keystroke history to 
consult, and  in this mode the backspace key would merely remove text "glyph 
by glyph", so to speak, as happens with ASCII text;  composition mode would 
be active when keystrokes have been recorded in a buffer, so that backspace 
could be used to "unstroke" the original strokes; the "unstroke" operations 
would mimic the order in which the originals were entered, even if the editor 
had optomized the composition.


On Wednesday 19 March 2014 20:43:05 Peter Constable wrote:
> If you click into the existing text in this email and backspace, what
> keystroke will you expect to be "erased"? Your system has no way of knowing
> what keystroke might have been involved in creating the text.
> What is _can_ make sense to talk about is to say that a user expects
> execution of a particular key sequence, such as pressing a Backspace key,
> to have a particular editing effect on the content of text. "Erasing a
> keystroke" and "keystrokes resulting in edits" are different things. One
> makes sense, the other does not.
> It may seem like I'm being pedantic, but I think the distinction is
> important. Our failure is in framing our thinking from years of experience
> (and perhaps some behaviours originally influenced by typewriter and
> teletype technologies) in which a keyboard has a bunch of keys that add
> characters, and variations on that that even include a lot of logic to get
> input keying sequences that can generate tens of thousands of different
> character; but then one or two keys (delete, backspace) that can only
> operate in very dumb ways. (We've also always assumed that any logic in
> keying behaviours can be conditioned only by the input sequences, but not
> by any existing content, but that steps beyond my earlier point.) These
> constraints in how we think limit possibilities

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