How does “cut and paste” affect character encoding and what can go wrong?

Question

I have a document A in encoding A displayed in tool A and a document B in encoding B displayed in tool B. If I cut and paste (part of) B into A what might be the resultant c

Answer 1

This is a very good question. When you copy/paste, exactly what is copied/pasted - CHARACTERS or BYTES?. And if BYTES, what encoding are they in?

From the answers, it sounds like the answer is "it depends". Different programs will put different things in the clipboard, sometimes placing multiple representations.

Then the pasting program needs to pick the best one and "do the right thing" with it.

Answer 2

First of all, a text editor's internal representation of text has no bearing on how the text is encoded (serialized) when you save the file. So a document is not "in" an encoding; it's a sequence of abstract characters. When the document is saved to a file (or transmitted over the network) then it gets encoded.

It's up to each application to decide what it puts on the clipboard. Typically, a windows app that knows what it's doing will put a number of different representations on the clipboard. When you paste in the other app, the app will look for the representation that best suits its need.

In your case, a text editor (that knows what it's doing) will put a Unicode representation of a selected string onto the clipboard (where Unicode, in Windows, is typically moved around as UTF-16, but that's not important). When you paste in the other app, it will insert that sequence of Unicode characters into the document at the selection point.

There's an app floating around called "ClipSpy" that will help you see what I'm talking about, interactively.