viml/parser/expressions: Add support for string parsing

3 files changed, 732 insertions, 2 deletions

diff --git a/test/symbolic/klee/nvim/keymap.c b/test/symbolic/klee/nvim/keymap.c
new file mode 100644
index 0000000000..c59d8d4d6e
--- /dev/null
+++ b/test/symbolic/klee/nvim/keymap.c
@@ -0,0 +1,540 @@
+#include <stdbool.h>
+
+#include "nvim/types.h"
+#include "nvim/keymap.h"
+#include "nvim/eval/typval.h"
+
+#define MOD_KEYS_ENTRY_SIZE 5
+
+static char_u modifier_keys_table[] =
+{
+  MOD_MASK_SHIFT, '&', '9',                   '@', '1',
+  MOD_MASK_SHIFT, '&', '0',                   '@', '2',
+  MOD_MASK_SHIFT, '*', '1',                   '@', '4',
+  MOD_MASK_SHIFT, '*', '2',                   '@', '5',
+  MOD_MASK_SHIFT, '*', '3',                   '@', '6',
+  MOD_MASK_SHIFT, '*', '4',                   'k', 'D',
+  MOD_MASK_SHIFT, '*', '5',                   'k', 'L',
+  MOD_MASK_SHIFT, '*', '7',                   '@', '7',
+  MOD_MASK_CTRL,  KS_EXTRA, (int)KE_C_END,    '@', '7',
+  MOD_MASK_SHIFT, '*', '9',                   '@', '9',
+  MOD_MASK_SHIFT, '*', '0',                   '@', '0',
+  MOD_MASK_SHIFT, '#', '1',                   '%', '1',
+  MOD_MASK_SHIFT, '#', '2',                   'k', 'h',
+  MOD_MASK_CTRL,  KS_EXTRA, (int)KE_C_HOME,   'k', 'h',
+  MOD_MASK_SHIFT, '#', '3',                   'k', 'I',
+  MOD_MASK_SHIFT, '#', '4',                   'k', 'l',
+  MOD_MASK_CTRL,  KS_EXTRA, (int)KE_C_LEFT,   'k', 'l',
+  MOD_MASK_SHIFT, '%', 'a',                   '%', '3',
+  MOD_MASK_SHIFT, '%', 'b',                   '%', '4',
+  MOD_MASK_SHIFT, '%', 'c',                   '%', '5',
+  MOD_MASK_SHIFT, '%', 'd',                   '%', '7',
+  MOD_MASK_SHIFT, '%', 'e',                   '%', '8',
+  MOD_MASK_SHIFT, '%', 'f',                   '%', '9',
+  MOD_MASK_SHIFT, '%', 'g',                   '%', '0',
+  MOD_MASK_SHIFT, '%', 'h',                   '&', '3',
+  MOD_MASK_SHIFT, '%', 'i',                   'k', 'r',
+  MOD_MASK_CTRL,  KS_EXTRA, (int)KE_C_RIGHT,  'k', 'r',
+  MOD_MASK_SHIFT, '%', 'j',                   '&', '5',
+  MOD_MASK_SHIFT, '!', '1',                   '&', '6',
+  MOD_MASK_SHIFT, '!', '2',                   '&', '7',
+  MOD_MASK_SHIFT, '!', '3',                   '&', '8',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_UP,     'k', 'u',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_DOWN,   'k', 'd',
+
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_XF1,    KS_EXTRA, (int)KE_XF1,
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_XF2,    KS_EXTRA, (int)KE_XF2,
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_XF3,    KS_EXTRA, (int)KE_XF3,
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_XF4,    KS_EXTRA, (int)KE_XF4,
+
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F1,     'k', '1',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F2,     'k', '2',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F3,     'k', '3',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F4,     'k', '4',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F5,     'k', '5',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F6,     'k', '6',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F7,     'k', '7',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F8,     'k', '8',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F9,     'k', '9',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F10,    'k', ';',
+
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F11,    'F', '1',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F12,    'F', '2',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F13,    'F', '3',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F14,    'F', '4',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F15,    'F', '5',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F16,    'F', '6',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F17,    'F', '7',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F18,    'F', '8',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F19,    'F', '9',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F20,    'F', 'A',
+
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F21,    'F', 'B',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F22,    'F', 'C',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F23,    'F', 'D',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F24,    'F', 'E',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F25,    'F', 'F',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F26,    'F', 'G',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F27,    'F', 'H',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F28,    'F', 'I',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F29,    'F', 'J',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F30,    'F', 'K',
+
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F31,    'F', 'L',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F32,    'F', 'M',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F33,    'F', 'N',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F34,    'F', 'O',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F35,    'F', 'P',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F36,    'F', 'Q',
+  MOD_MASK_SHIFT, KS_EXTRA, (int)KE_S_F37,    'F', 'R',
+
+  MOD_MASK_SHIFT, 'k', 'B',                   KS_EXTRA, (int)KE_TAB,
+
+  NUL
+};
+
+int simplify_key(const int key, int *modifiers)
+{
+  if (*modifiers & (MOD_MASK_SHIFT | MOD_MASK_CTRL | MOD_MASK_ALT)) {
+    // TAB is a special case.
+    if (key == TAB && (*modifiers & MOD_MASK_SHIFT)) {
+      *modifiers &= ~MOD_MASK_SHIFT;
+      return K_S_TAB;
+    }
+    const int key0 = KEY2TERMCAP0(key);
+    const int key1 = KEY2TERMCAP1(key);
+    for (int i = 0; modifier_keys_table[i] != NUL; i += MOD_KEYS_ENTRY_SIZE) {
+      if (key0 == modifier_keys_table[i + 3]
+          && key1 == modifier_keys_table[i + 4]
+          && (*modifiers & modifier_keys_table[i])) {
+        *modifiers &= ~modifier_keys_table[i];
+        return TERMCAP2KEY(modifier_keys_table[i + 1],
+                           modifier_keys_table[i + 2]);
+      }
+    }
+  }
+  return key;
+}
+
+int handle_x_keys(const int key)
+  FUNC_ATTR_CONST FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  switch (key) {
+    case K_XUP:     return K_UP;
+    case K_XDOWN:   return K_DOWN;
+    case K_XLEFT:   return K_LEFT;
+    case K_XRIGHT:  return K_RIGHT;
+    case K_XHOME:   return K_HOME;
+    case K_ZHOME:   return K_HOME;
+    case K_XEND:    return K_END;
+    case K_ZEND:    return K_END;
+    case K_XF1:     return K_F1;
+    case K_XF2:     return K_F2;
+    case K_XF3:     return K_F3;
+    case K_XF4:     return K_F4;
+    case K_S_XF1:   return K_S_F1;
+    case K_S_XF2:   return K_S_F2;
+    case K_S_XF3:   return K_S_F3;
+    case K_S_XF4:   return K_S_F4;
+  }
+  return key;
+}
+
+static const struct key_name_entry {
+  int key;  ///< Special key code or ASCII value.
+  const char *name;  ///< Name of the key
+} key_names_table[] = {
+  {' ',               "Space"},
+  {TAB,               "Tab"},
+  {K_TAB,             "Tab"},
+  {NL,                "NL"},
+  {NL,                "NewLine"},     // Alternative name
+  {NL,                "LineFeed"},    // Alternative name
+  {NL,                "LF"},          // Alternative name
+  {CAR,               "CR"},
+  {CAR,               "Return"},      // Alternative name
+  {CAR,               "Enter"},       // Alternative name
+  {K_BS,              "BS"},
+  {K_BS,              "BackSpace"},   // Alternative name
+  {ESC,               "Esc"},
+  {CSI,               "CSI"},
+  {K_CSI,             "xCSI"},
+  {'|',               "Bar"},
+  {'\\',              "Bslash"},
+  {K_DEL,             "Del"},
+  {K_DEL,             "Delete"},      // Alternative name
+  {K_KDEL,            "kDel"},
+  {K_UP,              "Up"},
+  {K_DOWN,            "Down"},
+  {K_LEFT,            "Left"},
+  {K_RIGHT,           "Right"},
+  {K_XUP,             "xUp"},
+  {K_XDOWN,           "xDown"},
+  {K_XLEFT,           "xLeft"},
+  {K_XRIGHT,          "xRight"},
+
+  {K_F1,              "F1"},
+  {K_F2,              "F2"},
+  {K_F3,              "F3"},
+  {K_F4,              "F4"},
+  {K_F5,              "F5"},
+  {K_F6,              "F6"},
+  {K_F7,              "F7"},
+  {K_F8,              "F8"},
+  {K_F9,              "F9"},
+  {K_F10,             "F10"},
+
+  {K_F11,             "F11"},
+  {K_F12,             "F12"},
+  {K_F13,             "F13"},
+  {K_F14,             "F14"},
+  {K_F15,             "F15"},
+  {K_F16,             "F16"},
+  {K_F17,             "F17"},
+  {K_F18,             "F18"},
+  {K_F19,             "F19"},
+  {K_F20,             "F20"},
+
+  {K_F21,             "F21"},
+  {K_F22,             "F22"},
+  {K_F23,             "F23"},
+  {K_F24,             "F24"},
+  {K_F25,             "F25"},
+  {K_F26,             "F26"},
+  {K_F27,             "F27"},
+  {K_F28,             "F28"},
+  {K_F29,             "F29"},
+  {K_F30,             "F30"},
+
+  {K_F31,             "F31"},
+  {K_F32,             "F32"},
+  {K_F33,             "F33"},
+  {K_F34,             "F34"},
+  {K_F35,             "F35"},
+  {K_F36,             "F36"},
+  {K_F37,             "F37"},
+
+  {K_XF1,             "xF1"},
+  {K_XF2,             "xF2"},
+  {K_XF3,             "xF3"},
+  {K_XF4,             "xF4"},
+
+  {K_HELP,            "Help"},
+  {K_UNDO,            "Undo"},
+  {K_INS,             "Insert"},
+  {K_INS,             "Ins"},         // Alternative name
+  {K_KINS,            "kInsert"},
+  {K_HOME,            "Home"},
+  {K_KHOME,           "kHome"},
+  {K_XHOME,           "xHome"},
+  {K_ZHOME,           "zHome"},
+  {K_END,             "End"},
+  {K_KEND,            "kEnd"},
+  {K_XEND,            "xEnd"},
+  {K_ZEND,            "zEnd"},
+  {K_PAGEUP,          "PageUp"},
+  {K_PAGEDOWN,        "PageDown"},
+  {K_KPAGEUP,         "kPageUp"},
+  {K_KPAGEDOWN,       "kPageDown"},
+
+  {K_KPLUS,           "kPlus"},
+  {K_KMINUS,          "kMinus"},
+  {K_KDIVIDE,         "kDivide"},
+  {K_KMULTIPLY,       "kMultiply"},
+  {K_KENTER,          "kEnter"},
+  {K_KPOINT,          "kPoint"},
+
+  {K_K0,              "k0"},
+  {K_K1,              "k1"},
+  {K_K2,              "k2"},
+  {K_K3,              "k3"},
+  {K_K4,              "k4"},
+  {K_K5,              "k5"},
+  {K_K6,              "k6"},
+  {K_K7,              "k7"},
+  {K_K8,              "k8"},
+  {K_K9,              "k9"},
+
+  {'<',               "lt"},
+
+  {K_MOUSE,           "Mouse"},
+  {K_LEFTMOUSE,       "LeftMouse"},
+  {K_LEFTMOUSE_NM,    "LeftMouseNM"},
+  {K_LEFTDRAG,        "LeftDrag"},
+  {K_LEFTRELEASE,     "LeftRelease"},
+  {K_LEFTRELEASE_NM,  "LeftReleaseNM"},
+  {K_MIDDLEMOUSE,     "MiddleMouse"},
+  {K_MIDDLEDRAG,      "MiddleDrag"},
+  {K_MIDDLERELEASE,   "MiddleRelease"},
+  {K_RIGHTMOUSE,      "RightMouse"},
+  {K_RIGHTDRAG,       "RightDrag"},
+  {K_RIGHTRELEASE,    "RightRelease"},
+  {K_MOUSEDOWN,       "ScrollWheelUp"},
+  {K_MOUSEUP,         "ScrollWheelDown"},
+  {K_MOUSELEFT,       "ScrollWheelRight"},
+  {K_MOUSERIGHT,      "ScrollWheelLeft"},
+  {K_MOUSEDOWN,       "MouseDown"},  // OBSOLETE: Use ScrollWheelXXX instead
+  {K_MOUSEUP,         "MouseUp"},    // Same
+  {K_X1MOUSE,         "X1Mouse"},
+  {K_X1DRAG,          "X1Drag"},
+  {K_X1RELEASE,       "X1Release"},
+  {K_X2MOUSE,         "X2Mouse"},
+  {K_X2DRAG,          "X2Drag"},
+  {K_X2RELEASE,       "X2Release"},
+  {K_DROP,            "Drop"},
+  {K_ZERO,            "Nul"},
+  {K_SNR,             "SNR"},
+  {K_PLUG,            "Plug"},
+  {K_PASTE,           "Paste"},
+  {K_FOCUSGAINED,     "FocusGained"},
+  {K_FOCUSLOST,       "FocusLost"},
+  {0,                 NULL}
+};
+
+int get_special_key_code(const char_u *name)
+{
+  for (int i = 0; key_names_table[i].name != NULL; i++) {
+    const char *const table_name = key_names_table[i].name;
+    int j;
+    for (j = 0; vim_isIDc(name[j]) && table_name[j] != NUL; j++) {
+      if (TOLOWER_ASC(table_name[j]) != TOLOWER_ASC(name[j])) {
+        break;
+      }
+    }
+    if (!vim_isIDc(name[j]) && table_name[j] == NUL) {
+      return key_names_table[i].key;
+    }
+  }
+
+  return 0;
+}
+
+
+static const struct modmasktable {
+  short mod_mask;  ///< Bit-mask for particular key modifier.
+  short mod_flag;  ///< Bit(s) for particular key modifier.
+  char_u name;  ///< Single letter name of modifier.
+} mod_mask_table[] = {
+  {MOD_MASK_ALT,              MOD_MASK_ALT,           (char_u)'M'},
+  {MOD_MASK_META,             MOD_MASK_META,          (char_u)'T'},
+  {MOD_MASK_CTRL,             MOD_MASK_CTRL,          (char_u)'C'},
+  {MOD_MASK_SHIFT,            MOD_MASK_SHIFT,         (char_u)'S'},
+  {MOD_MASK_MULTI_CLICK,      MOD_MASK_2CLICK,        (char_u)'2'},
+  {MOD_MASK_MULTI_CLICK,      MOD_MASK_3CLICK,        (char_u)'3'},
+  {MOD_MASK_MULTI_CLICK,      MOD_MASK_4CLICK,        (char_u)'4'},
+  {MOD_MASK_CMD,              MOD_MASK_CMD,           (char_u)'D'},
+  // 'A' must be the last one
+  {MOD_MASK_ALT,              MOD_MASK_ALT,           (char_u)'A'},
+  {0, 0, NUL}
+};
+
+int name_to_mod_mask(int c)
+{
+  c = TOUPPER_ASC(c);
+  for (size_t i = 0; mod_mask_table[i].mod_mask != 0; i++) {
+    if (c == mod_mask_table[i].name) {
+      return mod_mask_table[i].mod_flag;
+    }
+  }
+  return 0;
+}
+
+static int extract_modifiers(int key, int *modp)
+{
+  int modifiers = *modp;
+
+  if (!(modifiers & MOD_MASK_CMD)) {  // Command-key is special
+    if ((modifiers & MOD_MASK_SHIFT) && ASCII_ISALPHA(key)) {
+      key = TOUPPER_ASC(key);
+      modifiers &= ~MOD_MASK_SHIFT;
+    }
+  }
+  if ((modifiers & MOD_MASK_CTRL)
+      && ((key >= '?' && key <= '_') || ASCII_ISALPHA(key))) {
+    key = Ctrl_chr(key);
+    modifiers &= ~MOD_MASK_CTRL;
+    if (key == 0) {  // <C-@> is <Nul>
+      key = K_ZERO;
+    }
+  }
+
+  *modp = modifiers;
+  return key;
+}
+
+int find_special_key(const char_u **srcp, const size_t src_len, int *const modp,
+                     const bool keycode, const bool keep_x_key,
+                     const bool in_string)
+{
+  const char_u *last_dash;
+  const char_u *end_of_name;
+  const char_u *src;
+  const char_u *bp;
+  const char_u *const end = *srcp + src_len - 1;
+  int modifiers;
+  int bit;
+  int key;
+  uvarnumber_T n;
+  int l;
+
+  if (src_len == 0) {
+    return 0;
+  }
+
+  src = *srcp;
+  if (src[0] != '<') {
+    return 0;
+  }
+
+  // Find end of modifier list
+  last_dash = src;
+  for (bp = src + 1; bp <= end && (*bp == '-' || vim_isIDc(*bp)); bp++) {
+    if (*bp == '-') {
+      last_dash = bp;
+      if (bp + 1 <= end) {
+        l = utfc_ptr2len_len(bp + 1, (int)(end - bp) + 1);
+        // Anything accepted, like <C-?>.
+        // <C-"> or <M-"> are not special in strings as " is
+        // the string delimiter. With a backslash it works: <M-\">
+        if (end - bp > l && !(in_string && bp[1] == '"') && bp[2] == '>') {
+          bp += l;
+        } else if (end - bp > 2 && in_string && bp[1] == '\\'
+                   && bp[2] == '"' && bp[3] == '>') {
+          bp += 2;
+        }
+      }
+    }
+    if (end - bp > 3 && bp[0] == 't' && bp[1] == '_') {
+      bp += 3;  // skip t_xx, xx may be '-' or '>'
+    } else if (end - bp > 4 && STRNICMP(bp, "char-", 5) == 0) {
+      vim_str2nr(bp + 5, NULL, &l, STR2NR_ALL, NULL, NULL, 0);
+      bp += l + 5;
+      break;
+    }
+  }
+
+  if (bp <= end && *bp == '>') {  // found matching '>'
+    end_of_name = bp + 1;
+
+    /* Which modifiers are given? */
+    modifiers = 0x0;
+    for (bp = src + 1; bp < last_dash; bp++) {
+      if (*bp != '-') {
+        bit = name_to_mod_mask(*bp);
+        if (bit == 0x0) {
+          break;                // Illegal modifier name
+        }
+        modifiers |= bit;
+      }
+    }
+
+    // Legal modifier name.
+    if (bp >= last_dash) {
+      if (STRNICMP(last_dash + 1, "char-", 5) == 0
+          && ascii_isdigit(last_dash[6])) {
+        // <Char-123> or <Char-033> or <Char-0x33>
+        vim_str2nr(last_dash + 6, NULL, NULL, STR2NR_ALL, NULL, &n, 0);
+        key = (int)n;
+      } else {
+        int off = 1;
+
+        // Modifier with single letter, or special key name.
+        if (in_string && last_dash[1] == '\\' && last_dash[2] == '"') {
+          off = 2;
+        }
+        l = mb_ptr2len(last_dash + 1);
+        if (modifiers != 0 && last_dash[l + 1] == '>') {
+          key = PTR2CHAR(last_dash + off);
+        } else {
+          key = get_special_key_code(last_dash + off);
+          if (!keep_x_key) {
+            key = handle_x_keys(key);
+          }
+        }
+      }
+
+      // get_special_key_code() may return NUL for invalid
+      // special key name.
+      if (key != NUL) {
+        // Only use a modifier when there is no special key code that
+        // includes the modifier.
+        key = simplify_key(key, &modifiers);
+
+        if (!keycode) {
+          // don't want keycode, use single byte code
+          if (key == K_BS) {
+            key = BS;
+          } else if (key == K_DEL || key == K_KDEL) {
+            key = DEL;
+          }
+        }
+
+        // Normal Key with modifier:
+        // Try to make a single byte code (except for Alt/Meta modifiers).
+        if (!IS_SPECIAL(key)) {
+          key = extract_modifiers(key, &modifiers);
+        }
+
+        *modp = modifiers;
+        *srcp = end_of_name;
+        return key;
+      }
+    }
+  }
+  return 0;
+}
+
+char_u *add_char2buf(int c, char_u *s)
+{
+  char_u temp[MB_MAXBYTES + 1];
+  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.
+    if (c == K_SPECIAL) {
+      *s++ = K_SPECIAL;
+      *s++ = KS_SPECIAL;
+      *s++ = KE_FILLER;
+    } else {
+      *s++ = c;
+    }
+  }
+  return s;
+}
+
+unsigned int trans_special(const char_u **srcp, const size_t src_len,
+                           char_u *const dst, const bool keycode,
+                           const bool in_string)
+{
+  int modifiers = 0;
+  int key;
+  unsigned int dlen = 0;
+
+  key = find_special_key(srcp, src_len, &modifiers, keycode, false, in_string);
+  if (key == 0) {
+    return 0;
+  }
+
+  // Put the appropriate modifier in a string.
+  if (modifiers != 0) {
+    dst[dlen++] = K_SPECIAL;
+    dst[dlen++] = KS_MODIFIER;
+    dst[dlen++] = (char_u)modifiers;
+  }
+
+  if (IS_SPECIAL(key)) {
+    dst[dlen++] = K_SPECIAL;
+    dst[dlen++] = (char_u)KEY2TERMCAP0(key);
+    dst[dlen++] = KEY2TERMCAP1(key);
+  } else if (has_mbyte && !keycode) {
+    dlen += (unsigned int)(*mb_char2bytes)(key, dst + dlen);
+  } else if (keycode) {
+    char_u *after = add_char2buf(key, dst + dlen);
+    assert(after >= dst && (uintmax_t)(after - dst) <= UINT_MAX);
+    dlen = (unsigned int)(after - dst);
+  } else {
+    dst[dlen++] = (char_u)key;
+  }
+
+  return dlen;
+}
diff --git a/test/symbolic/klee/nvim/mbyte.c b/test/symbolic/klee/nvim/mbyte.c
index 394d17b700..bfc191b1b7 100644
--- a/test/symbolic/klee/nvim/mbyte.c
+++ b/test/symbolic/klee/nvim/mbyte.c
@@ -1,9 +1,89 @@
 #include <stddef.h>
+#include <inttypes.h>
+#include <assert.h>
+#include <stdbool.h>
 
 #include "nvim/types.h"
 #include "nvim/mbyte.h"
 #include "nvim/ascii.h"
 
+const uint8_t utf8len_tab_zero[] = {
+  //1 2 3 4 5 6 7 8 9 A B C D E F 0 1 2 3 4 5 6 7 8 9 A B C D E F
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,  // 0
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,  // 2
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,  // 4
+  1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,  // 6
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  // 8
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  // A
+  2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,  // C
+  3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,6,6,0,0,  // E
+};
+
+const uint8_t utf8len_tab[] = {
+  // ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9 ?A ?B ?C ?D ?E ?F
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 0?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 1?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 2?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 3?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 4?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 5?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 6?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 7?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 8?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // 9?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // A?
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  // B?
+  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,  // C?
+  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,  // D?
+  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,  // E?
+  4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 1, 1,  // F?
+};
+
+int utf_ptr2char(const char_u *const p)
+{
+  if (p[0] < 0x80) {  // Be quick for ASCII.
+    return p[0];
+  }
+
+  const uint8_t len = utf8len_tab_zero[p[0]];
+  if (len > 1 && (p[1] & 0xc0) == 0x80) {
+    if (len == 2) {
+      return ((p[0] & 0x1f) << 6) + (p[1] & 0x3f);
+    }
+    if ((p[2] & 0xc0) == 0x80) {
+      if (len == 3) {
+        return (((p[0] & 0x0f) << 12) + ((p[1] & 0x3f) << 6)
+                + (p[2] & 0x3f));
+      }
+      if ((p[3] & 0xc0) == 0x80) {
+        if (len == 4) {
+          return (((p[0] & 0x07) << 18) + ((p[1] & 0x3f) << 12)
+                  + ((p[2] & 0x3f) << 6) + (p[3] & 0x3f));
+        }
+        if ((p[4] & 0xc0) == 0x80) {
+          if (len == 5) {
+            return (((p[0] & 0x03) << 24) + ((p[1] & 0x3f) << 18)
+                    + ((p[2] & 0x3f) << 12) + ((p[3] & 0x3f) << 6)
+                    + (p[4] & 0x3f));
+          }
+          if ((p[5] & 0xc0) == 0x80 && len == 6) {
+            return (((p[0] & 0x01) << 30) + ((p[1] & 0x3f) << 24)
+                    + ((p[2] & 0x3f) << 18) + ((p[3] & 0x3f) << 12)
+                    + ((p[4] & 0x3f) << 6) + (p[5] & 0x3f));
+          }
+        }
+      }
+    }
+  }
+  // Illegal value: just return the first byte.
+  return p[0];
+}
+
+bool utf_composinglike(const char_u *p1, const char_u *p2)
+{
+  return false;
+}
+
 char_u *string_convert(const vimconv_T *conv, char_u *data, size_t *size)
 {
   return NULL;
@@ -11,8 +91,117 @@ char_u *string_convert(const vimconv_T *conv, char_u *data, size_t *size)
 
 int utfc_ptr2len_len(const char_u *p, int size)
 {
-  if (size < 1 || *p == NUL) {
+  assert(false);
+  return 0;
+}
+
+int utf_char2len(const int c)
+{
+  if (c < 0x80) {
+    return 1;
+  } else if (c < 0x800) {
+    return 2;
+  } else if (c < 0x10000) {
+    return 3;
+  } else if (c < 0x200000) {
+    return 4;
+  } else if (c < 0x4000000) {
+    return 5;
+  } else {
+    return 6;
+  }
+}
+
+int utf_char2bytes(const int c, char_u *const buf)
+{
+  if (c < 0x80) {  // 7 bits
+    buf[0] = c;
+    return 1;
+  } else if (c < 0x800) {  // 11 bits
+    buf[0] = 0xc0 + ((unsigned)c >> 6);
+    buf[1] = 0x80 + (c & 0x3f);
+    return 2;
+  } else if (c < 0x10000) {  // 16 bits
+    buf[0] = 0xe0 + ((unsigned)c >> 12);
+    buf[1] = 0x80 + (((unsigned)c >> 6) & 0x3f);
+    buf[2] = 0x80 + (c & 0x3f);
+    return 3;
+  } else if (c < 0x200000) {  // 21 bits
+    buf[0] = 0xf0 + ((unsigned)c >> 18);
+    buf[1] = 0x80 + (((unsigned)c >> 12) & 0x3f);
+    buf[2] = 0x80 + (((unsigned)c >> 6) & 0x3f);
+    buf[3] = 0x80 + (c & 0x3f);
+    return 4;
+  } else if (c < 0x4000000) {  // 26 bits
+    buf[0] = 0xf8 + ((unsigned)c >> 24);
+    buf[1] = 0x80 + (((unsigned)c >> 18) & 0x3f);
+    buf[2] = 0x80 + (((unsigned)c >> 12) & 0x3f);
+    buf[3] = 0x80 + (((unsigned)c >> 6) & 0x3f);
+    buf[4] = 0x80 + (c & 0x3f);
+    return 5;
+  } else {  // 31 bits
+    buf[0] = 0xfc + ((unsigned)c >> 30);
+    buf[1] = 0x80 + (((unsigned)c >> 24) & 0x3f);
+    buf[2] = 0x80 + (((unsigned)c >> 18) & 0x3f);
+    buf[3] = 0x80 + (((unsigned)c >> 12) & 0x3f);
+    buf[4] = 0x80 + (((unsigned)c >> 6) & 0x3f);
+    buf[5] = 0x80 + (c & 0x3f);
+    return 6;
+  }
+}
+
+int utf_ptr2len(const char_u *const p)
+{
+  if (*p == NUL) {
+    return 0;
+  }
+  const int len = utf8len_tab[*p];
+  for (int i = 1; i < len; i++) {
+    if ((p[i] & 0xc0) != 0x80) {
+      return 1;
+    }
+  }
+  return len;
+}
+
+int utfc_ptr2len(const char_u *const p)
+{
+  uint8_t b0 = (uint8_t)(*p);
+
+  if (b0 == NUL) {
     return 0;
   }
-  return 1;
+  if (b0 < 0x80 && p[1] < 0x80) {  // be quick for ASCII
+    return 1;
+  }
+
+  // Skip over first UTF-8 char, stopping at a NUL byte.
+  int len = utf_ptr2len(p);
+
+  // Check for illegal byte.
+  if (len == 1 && b0 >= 0x80) {
+    return 1;
+  }
+
+  // Check for composing characters.  We can handle only the first six, but
+  // skip all of them (otherwise the cursor would get stuck).
+  int prevlen = 0;
+  for (;;) {
+    if (p[len] < 0x80 || !UTF_COMPOSINGLIKE(p + prevlen, p + len)) {
+      return len;
+    }
+
+    // Skip over composing char.
+    prevlen = len;
+    len += utf_ptr2len(p + len);
+  }
+}
+
+void mb_copy_char(const char_u **fp, char_u **tp)
+{
+  const size_t l = utfc_ptr2len(*fp);
+
+  memmove(*tp, *fp, (size_t)l);
+  *tp += l;
+  *fp += l;
 }
diff --git a/test/symbolic/klee/viml_expressions_parser.c b/test/symbolic/klee/viml_expressions_parser.c
index 5ad592b99f..e1cea2d990 100644
--- a/test/symbolic/klee/viml_expressions_parser.c
+++ b/test/symbolic/klee/viml_expressions_parser.c
@@ -18,6 +18,7 @@
 #include "nvim/garray.c"
 #include "nvim/gettext.c"
 #include "nvim/viml/parser/expressions.c"
+#include "nvim/keymap.c"
 
 #define INPUT_SIZE 50