refactor: remove CSI unescaping and clean up related names and comments

src/nvim/api/vim.c

@@ -187,21 +187,23 @@ static void on_redraw_event(void **argv)
 /// On execution error: does not fail, but updates v:errmsg.
 ///
 /// To input sequences like <C-o> use |nvim_replace_termcodes()| (typically
-/// with escape_csi=true) to replace |keycodes|, then pass the result to
+/// with escape_ks=false) to replace |keycodes|, then pass the result to
 /// nvim_feedkeys().
 ///
 /// Example:
 /// <pre>
 ///     :let key = nvim_replace_termcodes("<C-o>", v:true, v:false, v:true)
-///     :call nvim_feedkeys(key, 'n', v:true)
+///     :call nvim_feedkeys(key, 'n', v:false)
 /// </pre>
 ///
 /// @param keys         to be typed
 /// @param mode         behavior flags, see |feedkeys()|
-/// @param escape_csi   If true, escape K_SPECIAL/CSI bytes in `keys`
+/// @param escape_ks    If true, escape K_SPECIAL bytes in `keys`
+///                     This should be false if you already used
+///                     |nvim_replace_termcodes()|, and true otherwise.
 /// @see feedkeys()
-/// @see vim_strsave_escape_csi
+/// @see vim_strsave_escape_ks
-void nvim_feedkeys(String keys, String mode, Boolean escape_csi)
+void nvim_feedkeys(String keys, String mode, Boolean escape_ks)
   FUNC_API_SINCE(1)
 {
   bool remap = true;
@@ -232,10 +234,10 @@ void nvim_feedkeys(String keys, String mode, Boolean escape_csi)
   }
 
   char *keys_esc;
-  if (escape_csi) {
+  if (escape_ks) {
-    // Need to escape K_SPECIAL and CSI before putting the string in the
+    // Need to escape K_SPECIAL before putting the string in the
     // typeahead buffer.
-    keys_esc = (char *)vim_strsave_escape_csi((char_u *)keys.data);
+    keys_esc = (char *)vim_strsave_escape_ks((char_u *)keys.data);
   } else {
     keys_esc = keys.data;
   }
@@ -245,7 +247,7 @@ void nvim_feedkeys(String keys, String mode, Boolean escape_csi)
     typebuf_was_filled = true;
   }
 
-  if (escape_csi) {
+  if (escape_ks) {
     xfree(keys_esc);
   }
 

src/nvim/edit.c

@@ -260,7 +260,7 @@ static colnr_T Insstart_blank_vcol;     // vcol for first inserted blank
 static bool update_Insstart_orig = true;  // set Insstart_orig to Insstart
 
 static char_u *last_insert = NULL;    // the text of the previous insert,
-                                      // K_SPECIAL and CSI are escaped
+                                      // K_SPECIAL is escaped
 static int last_insert_skip;      // nr of chars in front of previous insert
 static int new_insert_skip;       // nr of chars in front of current insert
 static int did_restart_edit;            // "restart_edit" when calling edit()
@@ -6817,7 +6817,7 @@ void free_last_insert(void)
 
 /// Add character "c" to buffer "s"
 ///
-/// Escapes the special meaning of K_SPECIAL and CSI, handles multi-byte
+/// Escapes the special meaning of K_SPECIAL, handles multi-byte
 /// characters.
 ///
 /// @param[in]  c  Character to add.
@@ -6831,7 +6831,7 @@ char_u *add_char2buf(int c, char_u *s)
   const int len = utf_char2bytes(c, temp);
   for (int i = 0; i < len; i++) {
     c = temp[i];
-    // Need to escape K_SPECIAL and CSI like in the typeahead buffer.
+    // Need to escape K_SPECIAL like in the typeahead buffer.
     if (c == K_SPECIAL) {
       *s++ = K_SPECIAL;
       *s++ = KS_SPECIAL;

src/nvim/ex_docmd.c

@@ -6204,7 +6204,6 @@ static void do_ucmd(exarg_T *eap)
           // K_SPECIAL has been put in the buffer as K_SPECIAL
           // KS_SPECIAL KE_FILLER, like for mappings, but
           // do_cmdline() doesn't handle that, so convert it back.
-          // Also change K_SPECIAL KS_EXTRA KE_CSI into CSI.
           len = ksp - p;
           if (len > 0) {
             memmove(q, p, len);
@@ -8627,7 +8626,7 @@ static void ex_normal(exarg_T *eap)
     return;
   }
 
-  // vgetc() expects a CSI and K_SPECIAL to have been escaped.  Don't do
+  // vgetc() expects K_SPECIAL to have been escaped.  Don't do
   // this for the K_SPECIAL leading byte, otherwise special keys will not
   // work.
   {
@@ -8636,8 +8635,7 @@ static void ex_normal(exarg_T *eap)
     // Count the number of characters to be escaped.
     for (p = eap->arg; *p != NUL; p++) {
       for (l = utfc_ptr2len(p) - 1; l > 0; l--) {
-        if (*++p == K_SPECIAL             // trailbyte K_SPECIAL or CSI
+        if (*++p == K_SPECIAL) {  // trailbyte K_SPECIAL
-            ) {
           len += 2;
         }
       }

src/nvim/getchar.c

@@ -59,25 +59,18 @@
 static int curscript = 0;
 FileDescriptor *scriptin[NSCRIPT] = { NULL };
 
-/*
+// These buffers are used for storing:
- * These buffers are used for storing:
+// - stuffed characters: A command that is translated into another command.
- * - stuffed characters: A command that is translated into another command.
+// - redo characters: will redo the last change.
- * - redo characters: will redo the last change.
+// - recorded characters: for the "q" command.
- * - recorded characters: for the "q" command.
+//
- *
+// The bytes are stored like in the typeahead buffer:
- * The bytes are stored like in the typeahead buffer:
+// - K_SPECIAL introduces a special key (two more bytes follow).  A literal
- * - K_SPECIAL introduces a special key (two more bytes follow).  A literal
+//   K_SPECIAL is stored as K_SPECIAL KS_SPECIAL KE_FILLER.
- *   K_SPECIAL is stored as K_SPECIAL KS_SPECIAL KE_FILLER.
+// These translations are also done on multi-byte characters!
- * - CSI introduces a GUI termcap code (also when gui.in_use is FALSE,
+//
- *   otherwise switching the GUI on would make mappings invalid).
+// Escaping K_SPECIAL is done by inchar().
- *   A literal CSI is stored as CSI KS_EXTRA KE_CSI.
+// Un-escaping is done by vgetc().
- * These translations are also done on multi-byte characters!
- *
- * Escaping CSI bytes is done by the system-specific input functions, called
- * by ui_inchar().
- * Escaping K_SPECIAL is done by inchar().
- * Un-escaping is done by vgetc().
- */
 
 #define MINIMAL_SIZE 20                 // minimal size for b_str
 
@@ -173,7 +166,7 @@ void free_buff(buffheader_T *buf)
 }
 
 /// Return the contents of a buffer as a single string.
-/// K_SPECIAL and CSI in the returned string are escaped.
+/// K_SPECIAL in the returned string is escaped.
 ///
 /// @param dozero  count == zero is not an error
 static char_u *get_buffcont(buffheader_T *buffer, int dozero)
@@ -202,11 +195,9 @@ static char_u *get_buffcont(buffheader_T *buffer, int dozero)
   return p;
 }
 
-/*
+/// Return the contents of the record buffer as a single string
- * Return the contents of the record buffer as a single string
+/// and clear the record buffer.
- * and clear the record buffer.
+/// K_SPECIAL in the returned string is escaped.
- * K_SPECIAL and CSI in the returned string are escaped.
- */
 char_u *get_recorded(void)
 {
   char_u *p;
@@ -236,10 +227,8 @@ char_u *get_recorded(void)
   return p;
 }
 
-/*
+/// Return the contents of the redo buffer as a single string.
- * Return the contents of the redo buffer as a single string.
+/// K_SPECIAL in the returned string is escaped.
- * K_SPECIAL and CSI in the returned string are escaped.
- */
 char_u *get_inserted(void)
 {
   return get_buffcont(&redobuff, FALSE);
@@ -247,7 +236,7 @@ char_u *get_inserted(void)
 
 /// Add string after the current block of the given buffer
 ///
-/// K_SPECIAL and CSI should have been escaped already.
+/// K_SPECIAL should have been escaped already.
 ///
 /// @param[out]  buf  Buffer to add to.
 /// @param[in]  s  String to add.
@@ -305,10 +294,8 @@ static void add_num_buff(buffheader_T *buf, long n)
   add_buff(buf, number, -1L);
 }
 
-/*
+/// Add character 'c' to buffer "buf".
- * Add character 'c' to buffer "buf".
+/// Translates special keys, NUL, K_SPECIAL and multibyte characters.
- * Translates special keys, NUL, CSI, K_SPECIAL and multibyte characters.
- */
 static void add_char_buff(buffheader_T *buf, int c)
 {
   uint8_t bytes[MB_MAXBYTES + 1];
@@ -340,12 +327,10 @@ static void add_char_buff(buffheader_T *buf, int c)
   }
 }
 
-/*
+/// Get one byte from the read buffers.  Use readbuf1 one first, use readbuf2
- * Get one byte from the read buffers.  Use readbuf1 one first, use readbuf2
+/// if that one is empty.
- * if that one is empty.
+/// If advance == TRUE go to the next char.
- * If advance == TRUE go to the next char.
+/// No translation is done K_SPECIAL is escaped.
- * No translation is done K_SPECIAL and CSI are escaped.
- */
 static int read_readbuffers(int advance)
 {
   int c;
@@ -524,10 +509,8 @@ void restoreRedobuff(save_redo_T *save_redo)
   old_redobuff = save_redo->sr_old_redobuff;
 }
 
-/*
+/// Append "s" to the redo buffer.
- * Append "s" to the redo buffer.
+/// K_SPECIAL should already have been escaped.
- * K_SPECIAL and CSI should already have been escaped.
- */
 void AppendToRedobuff(const char *s)
 {
   if (!block_redo) {
@@ -536,7 +519,7 @@ void AppendToRedobuff(const char *s)
 }
 
 /// Append to Redo buffer literally, escaping special characters with CTRL-V.
-/// K_SPECIAL and CSI are escaped as well.
+/// K_SPECIAL is escaped as well.
 ///
 /// @param str  String to append
 /// @param len  Length of `str` or -1 for up to the NUL.
@@ -584,10 +567,8 @@ void AppendToRedobuffLit(const char_u *str, int len)
   }
 }
 
-/*
+/// Append a character to the redo buffer.
- * Append a character to the redo buffer.
+/// Translates special keys, NUL, K_SPECIAL and multibyte characters.
- * Translates special keys, NUL, CSI, K_SPECIAL and multibyte characters.
- */
 void AppendCharToRedobuff(int c)
 {
   if (!block_redo) {
@@ -605,17 +586,15 @@ void AppendNumberToRedobuff(long n)
   }
 }
 
-/*
+/// Append string "s" to the stuff buffer.
- * Append string "s" to the stuff buffer.
+/// K_SPECIAL must already have been escaped.
- * CSI and K_SPECIAL must already have been escaped.
- */
 void stuffReadbuff(const char *s)
 {
   add_buff(&readbuf1, s, -1L);
 }
 
 /// Append string "s" to the redo stuff buffer.
-/// @remark CSI and K_SPECIAL must already have been escaped.
+/// @remark K_SPECIAL must already have been escaped.
 void stuffRedoReadbuff(const char *s)
 {
   add_buff(&readbuf2, s, -1L);
@@ -626,11 +605,9 @@ void stuffReadbuffLen(const char *s, long len)
   add_buff(&readbuf1, s, len);
 }
 
-/*
+/// Stuff "s" into the stuff buffer, leaving special key codes unmodified and
- * Stuff "s" into the stuff buffer, leaving special key codes unmodified and
+/// escaping other K_SPECIAL bytes.
- * escaping other K_SPECIAL and CSI bytes.
+/// Change CR, LF and ESC into a space.
- * Change CR, LF and ESC into a space.
- */
 void stuffReadbuffSpec(const char *s)
 {
   while (*s != NUL) {
@@ -648,10 +625,8 @@ void stuffReadbuffSpec(const char *s)
   }
 }
 
-/*
+/// Append a character to the stuff buffer.
- * Append a character to the stuff buffer.
+/// Translates special keys, NUL, K_SPECIAL and multibyte characters.
- * Translates special keys, NUL, CSI, K_SPECIAL and multibyte characters.
- */
 void stuffcharReadbuff(int c)
 {
   add_char_buff(&readbuf1, c);
@@ -665,12 +640,12 @@ void stuffnumReadbuff(long n)
   add_num_buff(&readbuf1, n);
 }
 
-// Read a character from the redo buffer.  Translates K_SPECIAL, CSI and
+/// Read a character from the redo buffer.  Translates K_SPECIAL and
-// multibyte characters.
+/// multibyte characters.
-// The redo buffer is left as it is.
+/// The redo buffer is left as it is.
-// If init is true, prepare for redo, return FAIL if nothing to redo, OK
+/// If init is true, prepare for redo, return FAIL if nothing to redo, OK
-// otherwise.
+/// otherwise.
-// If old_redo is true, use old_redobuff instead of redobuff.
+/// If old_redo is true, use old_redobuff instead of redobuff.
 static int read_redo(bool init, bool old_redo)
 {
   static buffblock_T *bp;
@@ -724,9 +699,9 @@ static int read_redo(bool init, bool old_redo)
   return c;
 }
 
-// Copy the rest of the redo buffer into the stuff buffer (in a slow way).
+/// Copy the rest of the redo buffer into the stuff buffer (in a slow way).
-// If old_redo is true, use old_redobuff instead of redobuff.
+/// If old_redo is true, use old_redobuff instead of redobuff.
-// The escaped K_SPECIAL and CSI are copied without translation.
+/// The escaped K_SPECIAL is copied without translation.
 static void copy_redo(bool old_redo)
 {
   int c;
@@ -1426,15 +1401,13 @@ static void updatescript(int c)
   }
 }
 
-/*
+/// Get the next input character.
- * Get the next input character.
+/// Can return a special key or a multi-byte character.
- * Can return a special key or a multi-byte character.
+/// Can return NUL when called recursively, use safe_vgetc() if that's not
- * Can return NUL when called recursively, use safe_vgetc() if that's not
+/// wanted.
- * wanted.
+/// This translates escaped K_SPECIAL bytes to a K_SPECIAL byte.
- * This translates escaped K_SPECIAL and CSI bytes to a K_SPECIAL or CSI byte.
+/// Collects the bytes of a multibyte character into the whole character.
- * Collects the bytes of a multibyte character into the whole character.
+/// Returns the modifiers in the global "mod_mask".
- * Returns the modifiers in the global "mod_mask".
- */
 int vgetc(void)
 {
   int c, c2;
@@ -1571,14 +1544,9 @@ int vgetc(void)
           buf[i] = (char_u)vgetorpeek(true);
           if (buf[i] == K_SPECIAL) {
             // Must be a K_SPECIAL - KS_SPECIAL - KE_FILLER sequence,
-            // which represents a K_SPECIAL (0x80),
+            // which represents a K_SPECIAL (0x80).
-            // or a CSI - KS_EXTRA - KE_CSI sequence, which represents
+            (void)vgetorpeek(true);  // skip KS_SPECIAL
-            // a CSI (0x9B),
+            (void)vgetorpeek(true);  // skip KE_FILLER
-            // of a K_SPECIAL - KS_EXTRA - KE_CSI, which is CSI too.
-            c = vgetorpeek(true);
-            if (vgetorpeek(true) == KE_CSI && c == KS_EXTRA) {
-              buf[i] = CSI;
-            }
           }
         }
         no_mapping--;
@@ -2042,7 +2010,7 @@ void vungetc(int c)
 ///
 /// When `no_mapping` (global) is zero, checks for mappings in the current mode.
 /// Only returns one byte (of a multi-byte character).
-/// K_SPECIAL and CSI may be escaped, need to get two more bytes then.
+/// K_SPECIAL may be escaped, need to get two more bytes then.
 static int vgetorpeek(bool advance)
 {
   int c, c1;
@@ -2572,7 +2540,7 @@ int fix_input_buffer(char_u *buf, int len)
   FUNC_ATTR_NONNULL_ALL
 {
   if (!using_script()) {
-    // Should not escape K_SPECIAL/CSI reading input from the user because vim
+    // Should not escape K_SPECIAL reading input from the user because vim
     // key codes keys are processed in input.c/input_enqueue.
     buf[len] = NUL;
     return len;
@@ -2583,9 +2551,8 @@ int fix_input_buffer(char_u *buf, int len)
   char_u *p = buf;
 
   // Two characters are special: NUL and K_SPECIAL.
-  // Replace         NUL by K_SPECIAL KS_ZERO    KE_FILLER
+  // Replace       NUL by K_SPECIAL KS_ZERO    KE_FILLER
   // Replace K_SPECIAL by K_SPECIAL KS_SPECIAL KE_FILLER
-  // Replace       CSI by K_SPECIAL KS_EXTRA   KE_CSI
   for (i = len; --i >= 0; ++p) {
     if (p[0] == NUL
         || (p[0] == K_SPECIAL
@@ -3476,10 +3443,10 @@ static void showmap(mapblock_T *mp, bool local)
   } else if (mp->m_str == NULL) {
     msg_puts_attr("<Nop>", HL_ATTR(HLF_8));
   } else {
-    // Remove escaping of CSI, because "m_str" is in a format to be used
+    // Remove escaping of K_SPECIAL, because "m_str" is in a format to be used
     // as typeahead.
     char_u *s = vim_strsave(mp->m_str);
-    vim_unescape_csi(s);
+    vim_unescape_ks(s);
     msg_outtrans_special(s, false, 0);
     xfree(s);
   }
@@ -3859,9 +3826,9 @@ bool check_abbr(int c, char_u *ptr, int col, int mincol)
       int match;
 
       if (strchr((const char *)mp->m_keys, K_SPECIAL) != NULL) {
-        // Might have CSI escaped mp->m_keys.
+        // Might have K_SPECIAL escaped mp->m_keys.
         q = vim_strsave(mp->m_keys);
-        vim_unescape_csi(q);
+        vim_unescape_ks(q);
         qlen = (int)STRLEN(q);
       }
       // find entries with right mode and keys
@@ -3907,7 +3874,7 @@ bool check_abbr(int c, char_u *ptr, int col, int mincol)
           int newlen = utf_char2bytes(c, tb + j);
           tb[j + newlen] = NUL;
           // Need to escape K_SPECIAL.
-          char_u *escaped = vim_strsave_escape_csi(tb + j);
+          char_u *escaped = vim_strsave_escape_ks(tb + j);
           if (escaped != NULL) {
             newlen = (int)STRLEN(escaped);
             memmove(tb + j, escaped, (size_t)newlen);
@@ -3960,11 +3927,11 @@ static char_u *eval_map_expr(mapblock_T  *mp, int c)
   int save_msg_col;
   int save_msg_row;
 
-  /* Remove escaping of CSI, because "str" is in a format to be used as
+  // Remove escaping of K_SPECIAL, because "str" is in a format to be used as
-   * typeahead. */
+  // typeahead.
   if (mp->m_luaref == LUA_NOREF) {
     expr = vim_strsave(mp->m_str);
-    vim_unescape_csi(expr);
+    vim_unescape_ks(expr);
   }
 
   save_cmd = save_cmdline_alloc();
@@ -4004,18 +3971,16 @@ static char_u *eval_map_expr(mapblock_T  *mp, int c)
   if (p == NULL) {
     return NULL;
   }
-  // Escape CSI in the result to be able to use the string as typeahead.
+  // Escape K_SPECIAL in the result to be able to use the string as typeahead.
-  res = vim_strsave_escape_csi(p);
+  res = vim_strsave_escape_ks(p);
   xfree(p);
 
   return res;
 }
 
-/*
+/// Copy "p" to allocated memory, escaping K_SPECIAL so that the result
- * Copy "p" to allocated memory, escaping K_SPECIAL and CSI so that the result
+/// can be put in the typeahead buffer.
- * can be put in the typeahead buffer.
+char_u *vim_strsave_escape_ks(char_u *p)
- */
-char_u *vim_strsave_escape_csi(char_u *p)
 {
   // Need a buffer to hold up to three times as much.  Four in case of an
   // illegal utf-8 byte:
@@ -4030,7 +3995,7 @@ char_u *vim_strsave_escape_csi(char_u *p)
       *d++ = *s++;
     } else {
       // Add character, possibly multi-byte to destination, escaping
-      // CSI and K_SPECIAL. Be careful, it can be an illegal byte!
+      // K_SPECIAL. Be careful, it can be an illegal byte!
       d = add_char2buf(utf_ptr2char(s), d);
       s += utf_ptr2len(s);
     }
@@ -4040,11 +4005,9 @@ char_u *vim_strsave_escape_csi(char_u *p)
   return res;
 }
 
-/*
+/// Remove escaping from K_SPECIAL characters.  Reverse of
- * Remove escaping from CSI and K_SPECIAL characters.  Reverse of
+/// vim_strsave_escape_ks().  Works in-place.
- * vim_strsave_escape_csi().  Works in-place.
+void vim_unescape_ks(char_u *p)
- */
-void vim_unescape_csi(char_u *p)
 {
   char_u *s = p, *d = p;
 
@@ -4052,10 +4015,6 @@ void vim_unescape_csi(char_u *p)
     if (s[0] == K_SPECIAL && s[1] == KS_SPECIAL && s[2] == KE_FILLER) {
       *d++ = K_SPECIAL;
       s += 3;
-    } else if ((s[0] == K_SPECIAL || s[0] == CSI)
-               && s[1] == KS_EXTRA && s[2] == (int)KE_CSI) {
-      *d++ = CSI;
-      s += 3;
     } else {
       *d++ = *s++;
     }
@@ -4298,7 +4257,7 @@ int put_escstr(FILE *fd, char_u *strstart, int what)
 
   for (; *str != NUL; str++) {
     // Check for a multi-byte character, which may contain escaped
-    // K_SPECIAL and CSI bytes.
+    // K_SPECIAL bytes.
     const char *p = mb_unescape((const char **)&str);
     if (p != NULL) {
       while (*p != NUL) {

src/nvim/input.c

@@ -105,7 +105,7 @@ int get_keystroke(MultiQueue *events)
     // terminal code to complete.
     n = os_inchar(buf + len, maxlen, len == 0 ? -1L : 100L, 0, events);
     if (n > 0) {
-      // Replace zero and CSI by a special key code.
+      // Replace zero and K_SPECIAL by a special key code.
       n = fix_input_buffer(buf + len, n);
       len += n;
       waited = 0;

src/nvim/keymap.c

@@ -963,7 +963,6 @@ char_u *replace_termcodes(const char_u *from, const size_t from_len, char_u **bu
     for (i = utfc_ptr2len_len(src, (int)(end - src) + 1); i > 0; i--) {
       // If the character is K_SPECIAL, replace it with K_SPECIAL
       // KS_SPECIAL KE_FILLER.
-      // If compiled with the GUI replace CSI with K_CSI.
       if (*src == K_SPECIAL) {
         result[dlen++] = K_SPECIAL;
         result[dlen++] = KS_SPECIAL;

src/nvim/keymap.h

@@ -220,7 +220,7 @@ enum key_extra {
   KE_KINS = 79,             // keypad Insert key
   KE_KDEL = 80,              // keypad Delete key
 
-  KE_CSI = 81,              // CSI typed directly (no longer produced by Nvim)
+  // KE_CSI = 81,           // Nvim doesn't need escaping CSI
   KE_SNR = 82,              // <SNR>
   KE_PLUG = 83,             // <Plug>
   KE_CMDWIN = 84,            // open command-line window from Command-line Mode

src/nvim/mbyte.c

@@ -2089,8 +2089,7 @@ const char *mb_unescape(const char **const pp)
   size_t buf_idx = 0;
   uint8_t *str = (uint8_t *)(*pp);
 
-  // Must translate K_SPECIAL KS_SPECIAL KE_FILLER to K_SPECIAL and CSI
+  // Must translate K_SPECIAL KS_SPECIAL KE_FILLER to K_SPECIAL.
-  // KS_EXTRA KE_CSI to CSI.
   // Maximum length of a utf-8 character is 4 bytes.
   for (size_t str_idx = 0; str[str_idx] != NUL && buf_idx < 4; str_idx++) {
     if (str[str_idx] == K_SPECIAL
@@ -2098,11 +2097,6 @@ const char *mb_unescape(const char **const pp)
         && str[str_idx + 2] == KE_FILLER) {
       buf[buf_idx++] = (char)K_SPECIAL;
       str_idx += 2;
-    } else if ((str[str_idx] == K_SPECIAL)
-               && str[str_idx + 1] == KS_EXTRA
-               && str[str_idx + 2] == KE_CSI) {
-      buf[buf_idx++] = (char)CSI;
-      str_idx += 2;
     } else if (str[str_idx] == K_SPECIAL) {
       break;  // A special key can't be a multibyte char.
     } else {

src/nvim/ops.c

@@ -922,8 +922,8 @@ int do_record(int c)
     // The recorded text contents.
     p = get_recorded();
     if (p != NULL) {
-      // Remove escaping for CSI and K_SPECIAL in multi-byte chars.
+      // Remove escaping for K_SPECIAL in multi-byte chars.
-      vim_unescape_csi(p);
+      vim_unescape_ks(p);
       (void)tv_dict_add_str(dict, S_LEN("regcontents"), (const char *)p);
     }
 
@@ -933,7 +933,7 @@ int do_record(int c)
     buf[1] = NUL;
     (void)tv_dict_add_str(dict, S_LEN("regname"), buf);
 
-    // Get the recorded key hits.  K_SPECIAL and CSI will be escaped, this
+    // Get the recorded key hits.  K_SPECIAL will be escaped, this
     // needs to be removed again to put it in a register.  exec_reg then
     // adds the escaping back later.
     apply_autocmds(EVENT_RECORDINGLEAVE, NULL, NULL, false, curbuf);
@@ -1099,7 +1099,7 @@ int do_execreg(int regname, int colon, int addcr, int silent)
           return FAIL;
         }
       }
-      escaped = vim_strsave_escape_csi(reg->y_array[i]);
+      escaped = vim_strsave_escape_ks(reg->y_array[i]);
       retval = ins_typebuf(escaped, remap, 0, true, silent);
       xfree(escaped);
       if (retval == FAIL) {
@@ -1141,7 +1141,7 @@ static void put_reedit_in_typebuf(int silent)
 /// Insert register contents "s" into the typeahead buffer, so that it will be
 /// executed again.
 ///
-/// @param esc    when true then it is to be taken literally: Escape CSI
+/// @param esc    when true then it is to be taken literally: Escape K_SPECIAL
 ///               characters and no remapping.
 /// @param colon  add ':' before the line
 static int put_in_typebuf(char_u *s, bool esc, bool colon, int silent)
@@ -1156,7 +1156,7 @@ static int put_in_typebuf(char_u *s, bool esc, bool colon, int silent)
     char_u *p;
 
     if (esc) {
-      p = vim_strsave_escape_csi(s);
+      p = vim_strsave_escape_ks(s);
     } else {
       p = s;
     }

test/functional/api/vim_spec.lua

@@ -1367,18 +1367,18 @@ describe('API', function()
   end)
 
   describe('nvim_feedkeys', function()
-    it('CSI escaping', function()
+    it('K_SPECIAL escaping', function()
       local function on_setup()
         -- notice the special char(…) \xe2\80\xa6
         nvim('feedkeys', ':let x1="…"\n', '', true)
 
         -- Both nvim_replace_termcodes and nvim_feedkeys escape \x80
         local inp = helpers.nvim('replace_termcodes', ':let x2="…"<CR>', true, true, true)
-        nvim('feedkeys', inp, '', true)   -- escape_csi=true
+        nvim('feedkeys', inp, '', true)   -- escape_ks=true
 
-        -- nvim_feedkeys with CSI escaping disabled
+        -- nvim_feedkeys with K_SPECIAL escaping disabled
         inp = helpers.nvim('replace_termcodes', ':let x3="…"<CR>', true, true, true)
-        nvim('feedkeys', inp, '', false)  -- escape_csi=false
+        nvim('feedkeys', inp, '', false)  -- escape_ks=false
 
         helpers.stop()
       end