fix: a lot of edge cases

.stylua.toml

@@ -1,4 +1,4 @@
-column_width = 80
+column_width = 120
 line_endings = "Unix"
 indent_type = "Spaces"
 indent_width = 4

lua/precognition/horizontal_motions.lua

@@ -0,0 +1,129 @@
+local utils = require("precognition.utils")
+
+local M = {}
+
+---@param str string
+---@param _cursorcol integer
+---@param _linelen integer
+---@return integer | nil
+function M.line_start_non_whitespace(str, _cursorcol, _linelen)
+    return str:find("%S") or 0
+end
+
+---@param _str string
+---@param _cursorcol integer
+---@param linelen integer
+---@return integer | nil
+function M.line_end(_str, _cursorcol, linelen)
+    return linelen or nil
+end
+
+---@param str string
+---@param cursorcol integer
+---@param _linelen integer
+---@return integer | nil
+function M.next_word_boundary(str, cursorcol, _linelen)
+    local offset = cursorcol
+    local len = vim.fn.strcharlen(str)
+    local char = vim.fn.strcharpart(str, offset - 1, 1)
+    local c_class = utils.char_class(char)
+
+    if c_class ~= 0 then
+        while utils.char_class(char) == c_class and offset <= len do
+            offset = offset + 1
+            char = vim.fn.strcharpart(str, offset - 1, 1)
+        end
+    end
+
+    while utils.char_class(char) == 0 and offset <= len do
+        offset = offset + 1
+        char = vim.fn.strcharpart(str, offset - 1, 1)
+    end
+    if offset > len then
+        return nil
+    end
+
+    return offset
+end
+
+---@param str string
+---@param cursorcol integer
+---@param _linelen integer
+---@return integer | nil
+function M.end_of_word(str, cursorcol, _linelen)
+    local len = vim.fn.strcharlen(str)
+    if cursorcol >= len then
+        return nil
+    end
+    local offset = cursorcol
+    local char = vim.fn.strcharpart(str, offset - 1, 1)
+    local c_class = utils.char_class(char)
+    local next_char_class = utils.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 = utils.char_class(char)
+        next_char_class = utils.char_class(vim.fn.strcharpart(str, (offset - 1) + 1, 1))
+    end
+
+    if c_class ~= 0 and next_char_class ~= 0 then
+        while utils.char_class(char) == c_class and offset <= len do
+            offset = offset + 1
+            char = vim.fn.strcharpart(str, offset - 1, 1)
+        end
+    end
+
+    if c_class == 0 or next_char_class == 0 then
+        local next_word_start = M.next_word_boundary(str, offset, 0)
+        if next_word_start then
+            rev_offset = M.end_of_word(str, next_word_start + 1, 0)
+        end
+    end
+
+    if rev_offset ~= nil and rev_offset <= 0 then
+        return nil
+    end
+
+    if rev_offset ~= nil then
+        return rev_offset
+    end
+    return offset - 1
+end
+
+---@param str string
+---@param cursorcol integer
+---@param _linelen integer
+---@return integer | nil
+function M.prev_word_boundary(str, cursorcol, _linelen)
+    local len = vim.fn.strcharlen(str)
+    local offset = cursorcol - 1
+    local char = vim.fn.strcharpart(str, offset - 1, 1)
+    local c_class = utils.char_class(char)
+
+    if c_class == 0 then
+        while utils.char_class(char) == 0 and offset >= 0 do
+            offset = offset - 1
+            char = vim.fn.strcharpart(str, offset - 1, 1)
+        end
+        c_class = utils.char_class(char)
+    end
+
+    while utils.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 offset > len or offset < 0 then
+        return nil
+    end
+    return offset + 1
+end
+
+return M