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I want to set viper-toggle-key to M-z (C-z is undo and only undo!). Looks easy: I just need to add (setq viper-toggle-key [(meta ?z)]) in .viper. Except I get this message:

Warning (initialization): An error occurred while loading `d:/Alexey/Home/.emacs.d/init.el':

error: Key sequence M-z starts with non-prefix key

I don't understand why: M-z is a single key, not a sequence!

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M is the meta key, which is usually not a modifier (like control) - typically it's something like ESC, which you type prior to the other character, e.g. ESC then z. So meta key combinations are, in general, sequences, rather than single keypresses.

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But why doesn't that imply that every <kbd>M-...</kbd> combination is a sequence? And one which starts with a non-prefix key? – Alexey Romanov Jun 27 '10 at 10:26

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