refactor: minor adjustments

lua/precognition/horizontal_motions.lua

@@ -132,11 +132,7 @@ function M.prev_word_boundary(str, cursorcol, linelen, big_word)
     while utils.char_class(char, big_word) == c_class and offset >= 0 do
         offset = offset - 1
         char = vim.fn.strcharpart(str, offset - 1, 1)
-        if char == "" then
-            -- Gone outside the line boundary, so break.
-            break
-        end
-        --if remaining string is whitespace, return nil_wrap
+        --if remaining string is whitespace, return 0
         local remaining = string.sub(str, offset)
         if remaining:match("^%s*$") and #remaining > 0 then
             return 0

lua/precognition/utils.lua

@@ -6,6 +6,7 @@ M.char_classes = {
     other = 1,
     word = 2,
     emoji = 3,
+    UNKNOWN = -1,
 }
 
 ---@param char string
@@ -17,7 +18,7 @@ function M.char_class(char, big_word)
 
     local byte = string.byte(char)
     if byte == nil then
-        return cc.other
+        return cc.UNKNOWN
     end
     if char == " " or char == "\t" or char == "\0" then
         return cc.whitespace

tests/precognition/char_spec.lua

@@ -9,6 +9,7 @@ describe("static classes", function()
         eq(cc.other, 1)
         eq(cc.word, 2)
         eq(cc.emoji, 3)
+        eq(cc.UNKNOWN, -1)
     end)
 end)