update debug log usage and add fanciness to log printing

stdlib/control_flow.go

@@ -45,8 +45,8 @@ func ShsProgn(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
  *    (if (eq (number "3") 3) (print "test passed") (print "test failed"))
  */
 func ShsIf(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
-    cond := in
-    t := cond.Next
+    cond := in.Copy()
+    t := cond.Next.Copy()
     f := t.Next
     cond.Next = nil
     t.Next = nil

stdlib/list.go

@@ -29,7 +29,7 @@ import (
  */
 func Expand(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
     if input.Tag != ast.LIST {
-        log.Log(log.DEBUG, "expand called on not a list", "expand")
+        log.Log(log.INFO, "expand called on not a list", "expand")
         return input
     }
 

stdlib/shell.go

@@ -68,7 +68,7 @@ var LastExitCode int
 func signalHandler() {
     for {
         <- sigChan
-        log.Log(log.DEBUG,
+        log.Log(log.INFO,
             "caught SIGINT",
             "jobctl")
 
@@ -174,7 +174,11 @@ func LaunchProcess(
     stderr io.Writer ) {
     c, cancel := context.WithCancel(context.Background())
     cmd := exec.CommandContext(c, path, args...)
-    cmd.SysProcAttr = &syscall.SysProcAttr{Foreground: !background, Setpgid: true}
+    cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+
+    if !background {
+        cmd.SysProcAttr.Foreground = true
+    }
 
     if stdin == nil {
         stdin = os.Stdin
@@ -201,6 +205,7 @@ func LaunchProcess(
     CurCancel = &cancel
 
     if background {
+        cmd.Process.Signal(syscall.SIGTSTP)
         go func(){
             waitChan <- cmd.Wait()
             delete(JobMap, cpid)
@@ -317,7 +322,7 @@ func Fg(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
     }
 
     ipid := int(pid)
-    proc, ok := JobMap[ipid]
+    _, ok := JobMap[ipid]
     if !ok {
         log.Log(log.ERR,
             "Process not found, was it started by this shell?",
@@ -325,17 +330,7 @@ func Fg(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
         return nil
     }
 
-    cmd := proc.Ctl
-    cmd.Process.Signal(syscall.SIGCONT)
-    err = cmd.Wait()
-    if err != nil {
-        if exitError, ok := err.(*exec.ExitError); ok {
-            LastExitCode = exitError.ExitCode()
-        } else {
-            log.Log(log.ERR, "Execution step returned error: " + err.Error(), "call")
-        }
-    }
-
+    tcsetpgrp(0, ipid)
     return nil
 }
 

stdlib/stdlib.go

@@ -238,7 +238,7 @@ func GenFuncTable() ast.FuncTable {
             Function:       Fg,
             Name: "foreground",
             TimesCalled:     0,
-            Args:            0,
+            Args:            1,
         },
 
         "$": &ast.Function{