feat: suspend jobs via ctrl z

this was a bit of a pain to add and it still doesnt work
properly on this commit, but this is how it would be done

api.go

@@ -47,6 +47,7 @@ var exports = map[string]util.LuaExport{
 	"interval": {hlinterval, 2, false},
 	"read": {hlread, 1, false},
 	"run": {hlrun, 1, true},
+	"suspend": {hlsuspend, 0, false},
 	"timeout": {hltimeout, 2, false},
 	"which": {hlwhich, 1, false},
 }
@@ -88,6 +89,12 @@ func hilbishLoad(rtm *rt.Runtime) (rt.Value, func()) {
 			if err != nil {
 				return nil, errors.New("hilbish.hinter has to be a function")
 			}
+		} else if k == "suspend" {
+			var err error
+			_, err = c.ClosureArg(2)
+			if err != nil {
+				return nil, errors.New("hilbish.suspend has to be a function")
+			}
 		} else if modVal := mod.Get(rt.StringValue(k)); modVal != rt.NilValue {
 			return nil, errors.New("not allowed to override in hilbish table")
 		}
@@ -213,7 +220,7 @@ func hlrun(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 	}
 
 	var exitcode uint8
-	stdout, stderr, err := execCommand(cmd, terminalOut)
+	stdout, stderr, err := execCommand(cmd, terminalOut, false)
 
 	if code, ok := interp.IsExitStatus(err); ok {
 		exitcode = code
@@ -643,3 +650,16 @@ func hlhinter(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 func hlhighlighter(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 	return c.Next(), nil
 }
+
+// suspend()
+// Suspends the currently running process. This can (and should be) overwritten if a
+// a different runner is being used.
+// --- @param line string
+func hlsuspend(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
+	if currentHandle != nil || currentHandle.Process != nil {
+		j := jobs.addFromHandler(currentCmd, currentHandle)
+		j.suspend()
+	}
+
+	return c.Next(), nil
+}

exec.go

@@ -27,6 +27,8 @@ import (
 var errNotExec = errors.New("not executable")
 var errNotFound = errors.New("not found")
 var runnerMode rt.Value = rt.StringValue("hybrid")
+var currentHandle *exec.Cmd
+var currentCmd string
 
 type execError struct{
 	typ string
@@ -233,7 +235,7 @@ func handleSh(cmdString string) (input string, exitCode uint8, cont bool, runErr
 }
 
 func execSh(cmdString string) (string, uint8, bool, error) {
-	_, _, err := execCommand(cmdString, true)
+	_, _, err := execCommand(cmdString, true, true)
 	if err != nil {
 		// If input is incomplete, start multiline prompting
 		if syntax.IsIncomplete(err) {
@@ -254,7 +256,7 @@ func execSh(cmdString string) (string, uint8, bool, error) {
 }
 
 // Run command in sh interpreter
-func execCommand(cmd string, terminalOut bool) (io.Writer, io.Writer, error) {
+func execCommand(cmd string, terminalOut, interactiveCall bool) (io.Writer, io.Writer, error) {
 	file, err := syntax.NewParser().Parse(strings.NewReader(cmd), "")
 	if err != nil {
 		return nil, nil, err
@@ -277,16 +279,21 @@ func execCommand(cmd string, terminalOut bool) (io.Writer, io.Writer, error) {
 	var bg bool
 	for _, stmt := range file.Stmts {
 		bg = false
-		if stmt.Background {
-			bg = true
 		printer.Print(buf, stmt.Cmd)
 
 		stmtStr := buf.String()
 		buf.Reset()
+
+		if interactiveCall {
+			currentCmd = stmtStr
+		}
+
+		if stmt.Background {
+			bg = true
 			jobs.add(stmtStr, []string{}, "")
 		}
 
-		interp.ExecHandler(execHandle(bg))(runner)
+		interp.ExecHandler(execHandle(bg, interactiveCall))(runner)
 		err = runner.Run(context.TODO(), stmt)
 		if err != nil {
 			return stdout, stderr, err
@@ -296,7 +303,7 @@ func execCommand(cmd string, terminalOut bool) (io.Writer, io.Writer, error) {
 	return stdout, stderr, nil
 }
 
-func execHandle(bg bool) interp.ExecHandlerFunc {
+func execHandle(bg, interactiveCall bool) interp.ExecHandlerFunc {
 	return func(ctx context.Context, args []string) error {
 		_, argstring := splitInput(strings.Join(args, " "))
 		// i dont really like this but it works
@@ -410,6 +417,10 @@ func execHandle(bg bool) interp.ExecHandlerFunc {
 			Stderr: hc.Stderr,
 		}
 
+		if interactiveCall {
+			currentHandle = &cmd
+		}
+
 		var j *job
 		if bg {
 			j = jobs.getLatest()
@@ -419,6 +430,8 @@ func execHandle(bg bool) interp.ExecHandlerFunc {
 			err = cmd.Start()
 		}
 
+		execDone := make(chan struct{}, 1)
+		var suspended bool
 		if err == nil {
 			if done := ctx.Done(); done != nil {
 				go func() {
@@ -440,12 +453,31 @@ func execHandle(bg bool) interp.ExecHandlerFunc {
 				}()
 			}
 
+			go func() {
+				hooks.On("job.suspend", func(args ...interface{}) {
+					fmt.Println("suspended")
+					val := args[0].(rt.Value)
+
+					_, ok := valueToJob(val)
+					if !ok {
+						return
+					}
+
+					suspended = true
+					execDone <- struct{}{}
+				})
+			}()
+			go func() {
 				err = cmd.Wait()
+				execDone <- struct{}{}
+			}()
+
+			<-execDone
 		}
 
 		exit := handleExecErr(err)
 
-		if bg {
+		if bg && !suspended {
 			j.exitCode = int(exit)
 			j.finish()
 		}

job.go

@@ -268,6 +268,18 @@ func (j *jobHandler) add(cmd string, args []string, path string) *job {
 	return jb
 }
 
+func (j *jobHandler) addFromHandler(cmd string, handler *exec.Cmd) *job {
+	jb := j.add(cmd, handler.Args, handler.Path)
+	if ps := handler.ProcessState; ps != nil {
+		if !ps.Exited() && ps.Pid() != 0 {
+			jb.running = true
+		}
+	}
+	jb.setHandle(handler)
+
+	return jb
+}
+
 func (j *jobHandler) getLatest() *job {
 	j.mu.RLock()
 	defer j.mu.RUnlock()

job_unix.go

@@ -8,6 +8,7 @@ import (
 	"syscall"
 	
 	"golang.org/x/sys/unix"
+	rt "github.com/arnodel/golua/runtime"
 )
 
 func (j *job) foreground() error {
@@ -36,3 +37,14 @@ func (j *job) background() error {
 	proc.Signal(syscall.SIGCONT)
 	return nil
 }
+
+func (j *job) suspend() error {
+	proc := j.handle.Process
+	if proc == nil {
+		return nil
+	}
+
+	proc.Signal(syscall.SIGSTOP)
+	hooks.Emit("job.suspend", rt.UserDataValue(j.ud))
+	return nil
+}

job_windows.go

@@ -13,3 +13,7 @@ func (j *job) foreground() error {
 func (j *job) background() error {
 	return errors.New("not supported on windows")
 }
+
+func (j *job) suspend() error {
+	return errors.New("not supported on windows")
+}

signal_unix.go

@@ -3,15 +3,18 @@
 package main
 
 import (
+	"fmt"
 	"syscall"
 	"os"
 	"os/signal"
+
+	rt "github.com/arnodel/golua/runtime"
 )
 
 func handleSignals() {
 	c := make(chan os.Signal)
-	signal.Ignore(syscall.SIGTTOU, syscall.SIGTTIN, syscall.SIGTSTP)
+	signal.Ignore(syscall.SIGTTOU, syscall.SIGTTIN)
-	signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGWINCH, syscall.SIGUSR1, syscall.SIGUSR2, syscall.SIGQUIT)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGWINCH, syscall.SIGUSR1, syscall.SIGUSR2, syscall.SIGQUIT, syscall.SIGTSTP)
 
 	for s := range c {
 		switch s {
@@ -20,6 +23,12 @@ func handleSignals() {
 			case syscall.SIGWINCH: hooks.Emit("signal.resize")
 			case syscall.SIGUSR1: hooks.Emit("signal.sigusr1")
 			case syscall.SIGUSR2: hooks.Emit("signal.sigusr2")
+			case syscall.SIGTSTP:
+				suspendHandler := hshMod.Get(rt.StringValue("suspend"))
+				_, err := rt.Call1(l.MainThread(), suspendHandler)
+				if err != nil {
+					fmt.Println(err)
+				}
 		}
 	}
 }