[Nano-devel] [PATCH] prompt: when asking for Yes/No/All, recognize also UTF-8 letters

[Benno Schulenberg]

Letters in other scripts than English often consist of multiple bytes.
When in a UTF-8 locale, correctly gather these bytes from the input and
put them together as the single letter that they are, before comparing
this letter against the translated "Yy", "Nn" and "Aa" strings.
---
 src/prompt.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/prompt.c b/src/prompt.c
index e7cb7418..eeb16ba7 100644
--- a/src/prompt.c
+++ b/src/prompt.c
@@ -659,15 +659,16 @@ int do_prompt(bool allow_tabs, bool allow_files,
 int do_yesno_prompt(bool all, const char *msg)
 {
        int response = -2, width = 16;
-       /* TRANSLATORS: For the next three strings, specify the single-byte
-        * starting letters of the translations for "Yes", "No", and "All".
-        * Of each string, the first letter is shown in the help lines. */
+       /* TRANSLATORS: For the next three strings, specify the starting letters
+        * of the translations for "Yes"/"No"/"All".  The first letter of each 
of
+        * these strings MUST be a single-byte letter; others may be 
multi-byte. */
        const char *yesstr = _("Yy");
        const char *nostr = _("Nn");
        const char *allstr = _("Aa");
 
        while (response == -2) {
-               int kbinput;
+               char letter[MAXCHARLEN + 1];
+               int kbinput, index = 0;
 
                if (!ISSET(NO_HELP)) {
                        char shortstr[MAXCHARLEN + 2];
@@ -710,16 +711,29 @@ int do_yesno_prompt(bool all, const char *msg)
                /* When not replacing, show the cursor while waiting for a key. 
*/
                kbinput = get_kbinput(bottomwin, !all);
 
-               /* See if the pressed key is in the Yes, No, or All strings. */
-#ifdef ENABLE_NLS
-               if (strchr(yesstr, kbinput) != NULL)
+#if defined(ENABLE_UTF8) && defined(ENABLE_NLS)
+               letter[index++] = (unsigned char)kbinput;
+
+               /* If the received code is a UTF-8 starter byte, get also the
+                * continuation bytes and assemble them into one letter. */
+               if (using_utf8() && 0xC0 <= kbinput && kbinput <= 0xF7) {
+                       int extras = (kbinput / 16) % 4 + (kbinput <= 0xCF ? 1 
: 0);
+
+                       while (extras <= get_key_buffer_len() && extras-- > 0)
+                               letter[index++] = (unsigned 
char)get_kbinput(bottomwin, !all);
+               }
+
+               letter[index] = '\0';
+
+               /* See if the typed letter is in the Yes, No, or All strings. */
+               if (strstr(yesstr, letter) != NULL)
                        response = 1;
-               else if (strchr(nostr, kbinput) != NULL)
+               else if (strstr(nostr, letter) != NULL)
                        response = 0;
-               else if (all && strchr(allstr, kbinput) != NULL)
+               else if (all && strstr(allstr, letter) != NULL)
                        response = 2;
                else
-#endif
+#endif /* ENABLE_UTF8 && ENABLE_NLS */
                if (strchr("Yy", kbinput) != NULL)
                        response = 1;
                else if (strchr("Nn", kbinput) != NULL)
-- 
2.17.0