feat: add exec function

this is basically the `exec` "command" in sh
itll replace hilbish with whatever provided
simple usage:
exec 'sleep 100'

README.md

@@ -60,11 +60,11 @@ sudo make install
 sudo make all
 ```
 
-Alternativly, if you use Arch Linux, you can compile Hilbish with an **(unofficial)** AUR package
+Alternatively, if you use Arch Linux, you can compile Hilbish with an **(unofficial)** AUR package:
 ```sh
 yay -S hilbish
 ```
-If you want the latest and greatest, you can install and compile from latest git commit  
+If you want the latest and greatest, you can install and compile from latest git commit: 
 ```sh
 yay -S hilbish-git
 ```

lua.go

@@ -3,7 +3,9 @@ package main
 import (
 	"fmt"
 	"os"
+	"os/exec"
 	"strings"
+	"syscall"
 
 	"hilbish/golibs/bait"
 	"hilbish/golibs/commander"
@@ -31,6 +33,7 @@ func LuaInit() {
 	l.SetGlobal("multiprompt", l.NewFunction(hshmlprompt))
 	l.SetGlobal("alias", l.NewFunction(hshalias))
 	l.SetGlobal("appendPath", l.NewFunction(hshappendPath))
+	l.SetGlobal("exec", l.NewFunction(hshexec))
 
 	// Add fs module to Lua
 	l.PreloadModule("fs", fs.Loader)
@@ -127,3 +130,19 @@ func hshappendPath(L *lua.LState) int {
 
 	return 0
 }
+
+func hshexec(L *lua.LState) int {
+	cmd := L.CheckString(1)
+	cmdArgs, _ := splitInput(cmd)
+	cmdPath, err := exec.LookPath(cmdArgs[0])
+	if err != nil {
+		fmt.Println(err)
+		// if we get here, cmdPath will be nothing
+		// therefore nothing will run
+	}
+
+	// syscall.Exec requires an absolute path to a binary
+	// path, args, string slice of environments
+	syscall.Exec(cmdPath, cmdArgs, os.Environ())
+	return 0
+}

main.go

@@ -35,6 +35,7 @@ var (
 	hooks bait.Bait
 	interactive bool
 	login bool // Are we the login shell?
+	noexecute bool // Should we run Lua or only report syntax errors
 )
 
 func main() {
@@ -47,14 +48,14 @@ func main() {
 	setshflag := getopt.BoolLong("setshellenv", 'S', "Sets $SHELL to Hilbish's executed path")
 	cmdflag := getopt.StringLong("command", 'c', "", /*TODO: Help description*/ "")
 	configflag := getopt.StringLong("config", 'C', defaultconfpath, "Sets the path to Hilbish's config")
-	// loginshflag
+	getopt.BoolLong("login", 'l', "Makes Hilbish act like a login shell")
-	// TODO: issue #37
+	getopt.BoolLong("interactive", 'i', "Force Hilbish to be an interactive shell")
-	_ = getopt.BoolLong("login", 'l', "Makes Hilbish act like a login shell")
+	getopt.BoolLong("noexec", 'n', "Don't execute and only report Lua syntax errors")
-	_ = getopt.BoolLong("interactive", 'i', "Force Hilbish to be an interactive shell")
 
 	getopt.Parse()
 	loginshflag := getopt.Lookup('l').Seen()
 	interactiveflag := getopt.Lookup('i').Seen()
+	noexecflag := getopt.Lookup('n').Seen()
 
 	if *cmdflag == "" || interactiveflag {
 		interactive = true
@@ -64,6 +65,10 @@ func main() {
 		interactive = false
 	}
 
+	if noexecflag {
+		noexecute = true
+	}
+
 	// first arg, first character
 	if loginshflag || os.Args[0][0] == '-' {
 		login = true
@@ -103,15 +108,12 @@ func main() {
 		}
 	}
 
-	go HandleSignals()
 	LuaInit()
+
 	RunLogin()
+	RunInput(*cmdflag)
 	RunConfig(*configflag)
 
-	readline.Completer = readline.FilenameCompleter
-	readline.LoadHistory(homedir + "/.hilbish-history")
-
-	RunInput(*cmdflag)
 	if getopt.NArgs() > 0 {
 		err := l.DoFile(getopt.Arg(0))
 		if err != nil {
@@ -121,6 +123,11 @@ func main() {
 		os.Exit(0)
 	}
 
+	readline.Completer = readline.FilenameCompleter
+	readline.LoadHistory(homedir + "/.hilbish-history")
+
+	go HandleSignals()
+
 	for interactive {
 		running = false
 

shell.go

@@ -16,9 +16,17 @@ import (
 )
 
 func RunInput(input string) {
-	// First try to run user input in Lua
+	// First try to load input, essentially compiling to bytecode
-	err := l.DoString(input)
+	fn, err := l.LoadString(input)
-
+	if err != nil && noexecute {
+		fmt.Println(err)
+		return
+	}
+	// And if there's no syntax errors and -n isnt provided, run
+	if !noexecute {
+		l.Push(fn)
+		err = l.PCall(0, lua.MultRet, nil)
+	}
 	if err == nil {
 		// If it succeeds, add to history and prompt again
 		HandleHistory(input)