key binding isearch-forward with Greek keyboard

Question

I use Emacs with various languages and have had trouble invoking isearch-forward from a keystroke when my keyboard layout (OS-level) is set to Greek. If I try the usual C-s, it says there is no binding for C-σ (since the 's' key is now the 'σ' key). I tried setting up a new key binding using global-set-key, switching to Greek, typing C-σ, switching back to English, and then indicating isearch-forward. This works fine for the first search, but I want to be able to hit C-σ again to search for the next occurrence, the way it works with C-s when my keyboard layout is set to English. But this doesn't work. Instead, it prompts me for a new search string. How can I set it up so that C-σ works exactly like C-s, so that I can hit C-σ again to advance to the next occurrence of my (Greek) search string? Of course I also want to do the same thing with C-ρ for isearch-backward.

Answer 1

Try binding keys also in isearch-mode-map. These keys are among those bound there by default, for example:

C-r    isearch-repeat-backward
C-s    isearch-repeat-forward
C-M-r  isearch-repeat-backward
C-M-s  isearch-repeat-forward
M-r    isearch-toggle-regexp
M-s r  isearch-toggle-regexp

For example:

(define-key isearch-mode-map (kbd "C-s") 'isearch-repeat-forward)

Instead of (kbd "C-s") you would substitute whatever key you also bound globally for Isearch.

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You can see all of the isearch-mode-map key bindings if you load library help-fns+.el. Just use C-h M-k isearch-mode-map.