completion: improve misspelling results

1 files changed, 61 insertions, 15 deletions

diff --git a/script/core/matchkey.lua b/script/core/matchkey.lua
index 83977496..eb67dac6 100644
--- a/script/core/matchkey.lua
+++ b/script/core/matchkey.lua
@@ -1,25 +1,44 @@
+local lowers = {}
+local uppers = {}
+for c in ('abcdefghijklmnopqrstuvwxyz'):gmatch '.' do
+    lowers[c] = true
+    uppers[c:upper()] = true
+end
+
 ---@param input string
 ---@param other string
----@param fast  boolean
----@return boolean isMatch
----@return number  deviation
-return function (input, other, fast)
-    if input == other then
-        return true, 0
+local function isValidFirstChar(input, other)
+    local first = input:sub(1, 1):upper()
+    if first == other:sub(1, 1):upper() then
+        return true
     end
-    if input == '' then
-        return true, 0
+    local pos, char = other:find(first, 2, true)
+    if not pos and uppers[first] then
+        -- word after symbol?
+        if other:find('%A' .. first:lower(), 2) then
+            return true
+        end
     end
-    if #input > #other then
-        return false, 0
+    if not char then
+        return false
+    end
+    -- symbol?
+    if not uppers[char] then
+        return true
+    end
+    -- word boundary?
+    local beforeChar = other:sub(pos - 1, pos - 1)
+    if not uppers[beforeChar] then
+        return true
     end
+    return false
+end
+
+local function isAlmostSame(input, other)
     local lMe = input:lower()
     local lOther = other:lower()
     if lMe == lOther:sub(1, #lMe) then
-        return true, 0
-    end
-    if fast and input:sub(1, 1) ~= other:sub(1, 1) then
-        return false, 0
+        return true
     end
     local chars = {}
     for i = 1, #lOther do
@@ -31,8 +50,35 @@ return function (input, other, fast)
         if chars[c] and chars[c] > 0 then
             chars[c] = chars[c] - 1
         else
-            return false, 0
+            return false
         end
     end
+    return true
+end
+
+---@param input string
+---@param other string
+---@param fast  boolean
+---@return boolean isMatch
+---@return number  deviation
+return function (input, other, fast)
+    if input == other then
+        return true, 0
+    end
+    if input == '' then
+        return true, 0
+    end
+    if #input > #other then
+        return false, 0
+    end
+    if fast and input:sub(1, 1) ~= other:sub(1, 1) then
+        return false, 0
+    end
+    if not isValidFirstChar(input, other) then
+        return false, 0
+    end
+    if not isAlmostSame(input, other) then
+        return false, 0
+    end
     return true, 1
 end