diff --git a/modules/crypto/crypto.go b/modules/crypto/crypto.go
index d4877e1..75189f4 100644
--- a/modules/crypto/crypto.go
+++ b/modules/crypto/crypto.go
@@ -204,10 +204,16 @@ func random_string(s *luajit.State) int {
 	}
 
 	charset := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
-	if s.GetTop() >= 2 {
+	if s.GetTop() >= 2 && !s.IsNil(2) {
 		charset = s.ToString(2)
 	}
 
+	if len(charset) == 0 {
+		s.PushNil()
+		s.PushString("empty charset")
+		return 2
+	}
+
 	result := make([]byte, length)
 	charsetLen := big.NewInt(int64(len(charset)))
 	for i := range result {
diff --git a/modules/registry.go b/modules/registry.go
index 46644ae..5fb9a47 100644
--- a/modules/registry.go
+++ b/modules/registry.go
@@ -1,4 +1,4 @@
-package registry
+package modules
 
 import (
 	"embed"
@@ -8,7 +8,11 @@ import (
 	"strings"
 	"sync"
 
-	"Moonshark/functions"
+	"Moonshark/modules/crypto"
+	"Moonshark/modules/fs"
+	"Moonshark/modules/json"
+	"Moonshark/modules/math"
+	lua_string "Moonshark/modules/string"
 
 	luajit "git.sharkk.net/Sky/LuaJIT-to-Go"
 )
@@ -16,7 +20,7 @@ import (
 // Global registry instance
 var Global *Registry
 
-//go:embed modules/*.lua
+//go:embed crypto/*.lua fs/*.lua json/*.lua math/*.lua string/*.lua
 var embeddedModules embed.FS
 
 // Registry manages all Lua modules and Go functions
@@ -33,33 +37,56 @@ func New() *Registry {
 		goFuncs: make(map[string]luajit.GoFunction),
 	}
 
-	// Load all Go functions
-	maps.Copy(r.goFuncs, functions.GetJSONFunctions())
-	maps.Copy(r.goFuncs, functions.GetStringFunctions())
-	maps.Copy(r.goFuncs, functions.GetMathFunctions())
-	maps.Copy(r.goFuncs, functions.GetFSFunctions())
-	maps.Copy(r.goFuncs, functions.GetCryptoFunctions())
+	// Load all Go functions from each module
+	maps.Copy(r.goFuncs, json.GetFunctionList())
+	maps.Copy(r.goFuncs, lua_string.GetFunctionList())
+	maps.Copy(r.goFuncs, math.GetFunctionList())
+	maps.Copy(r.goFuncs, fs.GetFunctionList())
+	maps.Copy(r.goFuncs, crypto.GetFunctionList())
 
 	return r
 }
 
 // LoadEmbeddedModules loads all .lua files from embedded filesystem
 func (r *Registry) LoadEmbeddedModules() error {
-	entries, err := embeddedModules.ReadDir("modules")
-	if err != nil {
-		return fmt.Errorf("failed to read modules directory: %w", err)
-	}
-
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
 
+	// Load modules from subdirectories
+	subdirs := []string{"crypto", "fs", "json", "math", "string"}
+	for _, subdir := range subdirs {
+		if err := r.loadModulesFromDir(subdir); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// loadModulesFromDir loads all .lua files from a specific directory
+func (r *Registry) loadModulesFromDir(dir string) error {
+	entries, err := embeddedModules.ReadDir(dir)
+	if err != nil {
+		return nil // Skip missing directories
+	}
+
 	for _, entry := range entries {
 		if entry.IsDir() || !strings.HasSuffix(entry.Name(), ".lua") {
 			continue
 		}
 
-		moduleName := strings.TrimSuffix(entry.Name(), ".lua")
-		source, err := embeddedModules.ReadFile(filepath.Join("modules", entry.Name()))
+		fileName := strings.TrimSuffix(entry.Name(), ".lua")
+
+		// If filename matches directory name (e.g., math/math.lua),
+		// register as just the directory name for require("math")
+		var moduleName string
+		if fileName == dir {
+			moduleName = dir
+		} else {
+			moduleName = dir + "/" + fileName
+		}
+
+		source, err := embeddedModules.ReadFile(filepath.Join(dir, entry.Name()))
 		if err != nil {
 			return fmt.Errorf("failed to read module %s: %w", moduleName, err)
 		}
@@ -138,15 +165,3 @@ func Initialize() error {
 	Global = New()
 	return Global.LoadEmbeddedModules()
 }
-
-// GetGoFunctions returns all Go functions
-func (r *Registry) GetGoFunctions() map[string]luajit.GoFunction {
-	r.mutex.RLock()
-	defer r.mutex.RUnlock()
-
-	result := make(map[string]luajit.GoFunction, len(r.goFuncs))
-	for k, v := range r.goFuncs {
-		result[k] = v
-	}
-	return result
-}
diff --git a/modules/string/string.go b/modules/string/string.go
index 68ab992..31b26f2 100644
--- a/modules/string/string.go
+++ b/modules/string/string.go
@@ -80,6 +80,15 @@ func string_join(s *luajit.State) int {
 				parts[i] = s.ToString(-1) // Convert via Lua
 			}
 		}
+	case map[string]any:
+		// Empty table {} from Lua becomes map[string]any{}
+		if len(v) == 0 {
+			parts = []string{} // Empty array
+		} else {
+			s.PushNil()
+			s.PushString("not an array")
+			return 2
+		}
 	default:
 		s.PushNil()
 		s.PushString("not an array")
diff --git a/modules/string/string.lua b/modules/string/string.lua
index 22c178a..fd9f980 100644
--- a/modules/string/string.lua
+++ b/modules/string/string.lua
@@ -163,6 +163,8 @@ end
 
 function str.lines(s)
 	if type(s) ~= "string" then error("str.lines: argument must be a string", 2) end
+	if s == "" then return {""} end
+	
 	s = s:gsub("\r\n", "\n"):gsub("\r", "\n")
 	local lines = {}
 	for line in (s .. "\n"):gmatch("([^\n]*)\n") do
@@ -485,7 +487,7 @@ end
 function str.slug(s)
 	if type(s) ~= "string" then error("str.slug: argument must be a string", 2) end
 	
-	local result = s:lower()
+	local result = str.remove_accents(s):lower()
 	result = result:gsub("[^%w%s]", "")
 	result = result:gsub("%s+", "-")
 	result = result:gsub("^%-+", ""):gsub("%-+$", "")
@@ -493,4 +495,155 @@ function str.slug(s)
 	return result
 end
 
+-- Add these functions to the end of string.lua, before the return statement
+
+function str.screaming_snake_case(s)
+	if type(s) ~= "string" then error("str.screaming_snake_case: argument must be a string", 2) end
+	return str.snake_case(s):upper()
+end
+
+function str.wrap(s, width)
+	if type(s) ~= "string" then error("str.wrap: first argument must be a string", 2) end
+	if type(width) ~= "number" or width <= 0 then error("str.wrap: width must be positive number", 2) end
+	
+	local words = str.words(s)
+	local lines = {}
+	local current_line = ""
+	
+	for _, word in ipairs(words) do
+		if current_line == "" then
+			current_line = word
+		elseif str.length(current_line .. " " .. word) <= width then
+			current_line = current_line .. " " .. word
+		else
+			table.insert(lines, current_line)
+			current_line = word
+		end
+	end
+	
+	if current_line ~= "" then
+		table.insert(lines, current_line)
+	end
+	
+	return lines
+end
+
+function str.dedent(s)
+	if type(s) ~= "string" then error("str.dedent: argument must be a string", 2) end
+	
+	local lines = str.lines(s)
+	if #lines == 0 then return "" end
+	
+	-- Find minimum indentation
+	local min_indent = math.huge
+	for _, line in ipairs(lines) do
+		if line:match("%S") then -- Non-empty line
+			local indent = line:match("^(%s*)")
+			min_indent = math.min(min_indent, #indent)
+		end
+	end
+	
+	if min_indent == math.huge then min_indent = 0 end
+	
+	-- Remove common indentation
+	local result = {}
+	for _, line in ipairs(lines) do
+		table.insert(result, line:sub(min_indent + 1))
+	end
+	
+	return table.concat(result, "\n")
+end
+
+function str.shell_quote(s)
+	if type(s) ~= "string" then error("str.shell_quote: argument must be a string", 2) end
+	
+	if s:match("^[%w%-%./]+$") then
+		return s -- No quoting needed
+	end
+	
+	-- Replace single quotes with '"'"'
+	local quoted = s:gsub("'", "'\"'\"'")
+	return "'" .. quoted .. "'"
+end
+
+function str.iequals(a, b)
+	if type(a) ~= "string" then error("str.iequals: first argument must be a string", 2) end
+	if type(b) ~= "string" then error("str.iequals: second argument must be a string", 2) end
+	return str.lower(a) == str.lower(b)
+end
+
+function str.template_advanced(template, context)
+	if type(template) ~= "string" then error("str.template_advanced: first argument must be a string", 2) end
+	context = context or {}
+	if type(context) ~= "table" then error("str.template_advanced: second argument must be a table", 2) end
+	
+	return template:gsub("%${([%w_.]+)}", function(path)
+		local keys = str.split(path, ".")
+		local value = context
+		
+		for _, key in ipairs(keys) do
+			if type(value) == "table" and value[key] ~= nil then
+				value = value[key]
+			else
+				return ""
+			end
+		end
+		
+		return tostring(value)
+	end)
+end
+
+function str.is_whitespace(s)
+	if type(s) ~= "string" then error("str.is_whitespace: argument must be a string", 2) end
+	return s:match("^%s*$") ~= nil
+end
+
+function str.strip_whitespace(s)
+	if type(s) ~= "string" then error("str.strip_whitespace: argument must be a string", 2) end
+	return s:gsub("%s", "")
+end
+
+function str.normalize_whitespace(s)
+	if type(s) ~= "string" then error("str.normalize_whitespace: argument must be a string", 2) end
+	return str.trim(s:gsub("%s+", " "))
+end
+
+function str.extract_numbers(s)
+	if type(s) ~= "string" then error("str.extract_numbers: argument must be a string", 2) end
+	
+	local numbers = {}
+	for match in s:gmatch("%-?%d+%.?%d*") do
+		local num = tonumber(match)
+		if num then
+			table.insert(numbers, num)
+		end
+	end
+	return numbers
+end
+
+function str.remove_accents(s)
+	if type(s) ~= "string" then error("str.remove_accents: argument must be a string", 2) end
+	
+	local accents = {
+		["à"] = "a", ["á"] = "a", ["â"] = "a", ["ã"] = "a", ["ä"] = "a", ["å"] = "a",
+		["è"] = "e", ["é"] = "e", ["ê"] = "e", ["ë"] = "e",
+		["ì"] = "i", ["í"] = "i", ["î"] = "i", ["ï"] = "i",
+		["ò"] = "o", ["ó"] = "o", ["ô"] = "o", ["õ"] = "o", ["ö"] = "o",
+		["ù"] = "u", ["ú"] = "u", ["û"] = "u", ["ü"] = "u",
+		["ñ"] = "n", ["ç"] = "c", ["ÿ"] = "y",
+		["À"] = "A", ["Á"] = "A", ["Â"] = "A", ["Ã"] = "A", ["Ä"] = "A", ["Å"] = "A",
+		["È"] = "E", ["É"] = "E", ["Ê"] = "E", ["Ë"] = "E",
+		["Ì"] = "I", ["Í"] = "I", ["Î"] = "I", ["Ï"] = "I",
+		["Ò"] = "O", ["Ó"] = "O", ["Ô"] = "O", ["Õ"] = "O", ["Ö"] = "O",
+		["Ù"] = "U", ["Ú"] = "U", ["Û"] = "U", ["Ü"] = "U",
+		["Ñ"] = "N", ["Ç"] = "C", ["Ÿ"] = "Y"
+	}
+	
+	local result = s
+	for accented, plain in pairs(accents) do
+		result = result:gsub(accented, plain)
+	end
+	return result
+end
+
 return str
\ No newline at end of file
diff --git a/moonshark.go b/moonshark.go
index fd143e7..03c6813 100644
--- a/moonshark.go
+++ b/moonshark.go
@@ -5,7 +5,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"Moonshark/registry"
+	"Moonshark/modules"
 
 	luajit "git.sharkk.net/Sky/LuaJIT-to-Go"
 )
@@ -25,7 +25,7 @@ func main() {
 	}
 
 	// Initialize global registry
-	if err := registry.Initialize(); err != nil {
+	if err := modules.Initialize(); err != nil {
 		fmt.Fprintf(os.Stderr, "Error: failed to initialize registry: %v\n", err)
 		os.Exit(1)
 	}
@@ -39,7 +39,7 @@ func main() {
 	defer state.Close()
 
 	// Install module system in main state
-	if err := registry.Global.InstallInState(state); err != nil {
+	if err := modules.Global.InstallInState(state); err != nil {
 		fmt.Fprintf(os.Stderr, "Error: failed to install module system: %v\n", err)
 		os.Exit(1)
 	}