fix: a lot of edge cases

lua/precognition/init.lua

@@ -25,8 +25,8 @@ local default = {
         ["$"] = { text = "$", prio = 1 },
         ["w"] = { text = "w", prio = 10 },
         -- ["W"] = "W",
-        ["b"] = { text = "b", prio = 10 },
-        ["e"] = { text = "e", prio = 10 },
+        ["b"] = { text = "b", prio = 9 },
+        ["e"] = { text = "e", prio = 8 },
         -- ["ge"] = "ge", -- should we support multi-char / multi-byte hints?
     },
     gutterHints = {
@@ -81,27 +81,27 @@ end
 ---@param start integer
 ---@return integer | nil
 local function next_word_boundary(str, start)
-    local offset = start - 1
+    local offset = start
     local len = vim.fn.strcharlen(str)
-    local char = vim.fn.strcharpart(str, offset, 1)
+    local char = vim.fn.strcharpart(str, offset - 1, 1)
     local c_class = char_class(char)
 
     if c_class ~= 0 then
         while char_class(char) == c_class and offset <= len do
             offset = offset + 1
-            char = vim.fn.strcharpart(str, offset, 1)
+            char = vim.fn.strcharpart(str, offset - 1, 1)
         end
     end
 
     while char_class(char) == 0 and offset <= len do
         offset = offset + 1
-        char = vim.fn.strcharpart(str, offset, 1)
+        char = vim.fn.strcharpart(str, offset - 1, 1)
     end
-    if (offset + 1) > len then
+    if offset > len then
         return nil
     end
 
-    return offset + 1
+    return offset
 end
 
 ---@param str string
@@ -112,16 +112,28 @@ local function end_of_word(str, start)
     if start >= len then
         return nil
     end
-    local offset = start - 1
-    local char = vim.fn.strcharpart(str, offset, 1)
+    local offset = start
+    local char = vim.fn.strcharpart(str, offset - 1, 1)
     local c_class = char_class(char)
-    local next_char_class = char_class(vim.fn.strcharpart(str, offset + 1, 1))
+    local next_char_class =
+        char_class(vim.fn.strcharpart(str, (offset - 1) + 1, 1))
     local rev_offset
 
+    if
+        (c_class == 1 and next_char_class ~= 1)
+        or (next_char_class == 1 and c_class ~= 1)
+    then
+        offset = offset + 1
+        char = vim.fn.strcharpart(str, offset - 1, 1)
+        c_class = char_class(char)
+        next_char_class =
+            char_class(vim.fn.strcharpart(str, (offset - 1) + 1, 1))
+    end
+
     if c_class ~= 0 and next_char_class ~= 0 then
         while char_class(char) == c_class and offset <= len do
             offset = offset + 1
-            char = vim.fn.strcharpart(str, offset, 1)
+            char = vim.fn.strcharpart(str, offset - 1, 1)
         end
     end
 
@@ -139,41 +151,40 @@ local function end_of_word(str, start)
     if rev_offset ~= nil then
         return rev_offset
     end
-    return offset
+    return offset - 1
 end
 
 ---@param str string
 ---@param start integer
 ---@return integer | nil
 local function prev_word_boundary(str, start)
     local len = vim.fn.strcharlen(str)
-    local offset = len - start + 1
-    str = string.reverse(str)
+    local offset = start - 1
     local char = vim.fn.strcharpart(str, offset - 1, 1)
     local c_class = char_class(char)
 
     if c_class == 0 then
-        while char_class(char) == 0 and offset <= len do
-            offset = offset + 1
-            char = vim.fn.strcharpart(str, offset, 1)
+        while char_class(char) == 0 and offset >= 0 do
+            offset = offset - 1
+            char = vim.fn.strcharpart(str, offset - 1, 1)
         end
+        c_class = char_class(char)
     end
 
-    c_class = char_class(char)
-    while char_class(char) == c_class and offset <= len do
-        offset = offset + 1
-        char = vim.fn.strcharpart(str, offset, 1)
+    while char_class(char) == c_class and offset >= 0 do
+        offset = offset - 1
+        char = vim.fn.strcharpart(str, offset - 1, 1)
         --if remaining string is whitespace, return nil_wrap
         local remaining = string.sub(str, offset)
         if remaining:match("^%s*$") and #remaining > 0 then
             return nil
         end
     end
 
-    if offset == nil or (len - offset + 1) > len or (len - offset + 1) <= 0 then
+    if offset == nil or offset > len or offset < 0 then
         return nil
     end
-    return len - offset + 1
+    return offset + 1
 end
 
 ---@param marks Precognition.VirtLine
@@ -254,9 +265,12 @@ local function apply_gutter_hints(gutter_hints, buf)
             if ok then
                 gutter_signs_cache[hint] = { line = loc, id = res }
             end
-            if not ok then
+            if not ok and loc ~= 0 then
                 vim.notify_once(
-                    "Failed to place sign: " .. config.gutterHints[hint].text,
+                    "Failed to place sign: "
+                        .. config.gutterHints[hint].text
+                        .. " at line "
+                        .. loc,
                     vim.log.levels.WARN
                 )
             end

tests/precognition/char_spec.lua

@@ -199,6 +199,13 @@ describe("boundaries", function()
             )
             eq(
                 5,
+                precognition.prev_word_boundary(
+                    "    myFunction(example, stuff)",
+                    15
+                )
+            )
+            eq(
+                15,
                 precognition.prev_word_boundary(
                     "    myFunction(example, stuff)",
                     16
@@ -226,7 +233,7 @@ describe("boundaries", function()
                 )
             )
             eq(
-                24,
+                23,
                 precognition.prev_word_boundary(
                     "    myFunction(example, stuff)",
                     25
@@ -260,9 +267,13 @@ describe("boundaries", function()
                     29
                 )
             )
-            --TODO: This isnt right, it should ne 25, but i dont know the rules
-            --there is something odd if there is only one class 2 under the cursor
-            -- eq(25, precognition.prev_word_boundary("    myFunction(example, stuff)", 30))
+            eq(
+                25,
+                precognition.prev_word_boundary(
+                    "    myFunction(example, stuff)",
+                    30
+                )
+            )
         end)
 
         it("can walk string with b", function()
@@ -307,10 +318,14 @@ describe("boundaries", function()
                 14,
                 precognition.end_of_word("    myFunction(example, stuff)", 5)
             )
-            --TODO: These next two dont work either for the same reason as the previous
-            --something to do with the bracket being under the cursor
-            -- eq(15, precognition.end_of_word("    myFunction(example, stuff)", 14))
-            -- eq(22, precognition.end_of_word("    myFunction(example, stuff)", 15))
+            eq(
+                15,
+                precognition.end_of_word("    myFunction(example, stuff)", 14)
+            )
+            eq(
+                22,
+                precognition.end_of_word("    myFunction(example, stuff)", 15)
+            )
             eq(
                 22,
                 precognition.end_of_word("    myFunction(example, stuff)", 16)
@@ -328,7 +343,7 @@ describe("boundaries", function()
                 precognition.end_of_word("    myFunction(example, stuff)", 25)
             )
             eq(
-                29,
+                30,
                 precognition.end_of_word("    myFunction(example, stuff)", 29)
             )
             eq(
@@ -337,4 +352,38 @@ describe("boundaries", function()
             )
         end)
     end)
+
+    describe("edge case", function()
+        it("can handle empty strings", function()
+            eq(nil, precognition.next_word_boundary("", 1))
+            eq(nil, precognition.prev_word_boundary("", 1))
+            eq(nil, precognition.end_of_word("", 1))
+        end)
+
+        it("can handle strings with only whitespace", function()
+            eq(nil, precognition.next_word_boundary(" ", 1))
+            eq(nil, precognition.prev_word_boundary(" ", 1))
+            eq(nil, precognition.end_of_word(" ", 1))
+        end)
+
+        it(
+            "can handle strings with special characters in the middle",
+            function()
+                local str = "vim.keymap.set('n', '<leader>t;', ':Test<CR>')"
+                eq(5, precognition.next_word_boundary(str, 4))
+                eq(1, precognition.prev_word_boundary(str, 4))
+                eq(10, precognition.end_of_word(str, 4))
+            end
+        )
+
+        it(
+            "can handle strings with multiple consecutive special characters",
+            function()
+                local str = "this || that"
+                eq(9, precognition.next_word_boundary(str, 6))
+                eq(1, precognition.prev_word_boundary(str, 6))
+                eq(7, precognition.end_of_word(str, 6))
+            end
+        )
+    end)
 end)