func ShowOnOff(subcmdName string, on bool) {
	if on {
		gub.Msg("%s is on.", subcmdName)
	} else {
		gub.Msg("%s is off.", subcmdName)
	}
}

// InfoPackageCommand implements the command:
//    info package [*name* ]
// which show information about a package or lists all packages.
func InfoPackageSubcmd(args []string) {
	if len(args) > 2 {
		for _, pkg_name := range args[2:len(args)] {
			if pkg := gub.Program().PackagesByName[pkg_name]; pkg != nil {
				gub.Msg("Package %s: \"%s\"", pkg_name, pkg.Object.Path())
				gub.Section("Package members:")
				var names []string
				for k, _ := range pkg.Members {
					names = append(names, k)
				}
				sort.Strings(names)
				opts := columnize.DefaultOptions()
				opts.DisplayWidth = gub.Maxwidth
				opts.LinePrefix = "  "
				mems := strings.TrimRight(columnize.Columnize(names, opts),
					"\n")
				gub.Msg(mems)

			} else {
				gub.Errmsg("Package %s not imported", pkg_name)
			}
		}
	} else {
		pkgNames := []string{}
		for pkg := range gub.Program().PackagesByName {
			pkgNames = append(pkgNames, pkg)
		}
		gub.PrintSorted("All imported packages", pkgNames)
	}
}

// InfoBreakpointSubcmd implements the debugger command:
//   info breakpoint
//
// This command shows status of user-settable breakpoints. If no
// breakpoint numbers are given, the show all breakpoints. Otherwise
// only those breakpoints listed are shown and the order given.
//
// The "Disp" column contains one of "keep", "del", the disposition of
// the breakpoint after it gets hit.
//
// The "enb" column indicates whether the breakpoint is enabled.
//
// The "Where" column indicates where the breakpoint is located.
// Status of user-settable breakpoints.
func InfoBreakpointSubcmd(args []string) {
	if gub.IsBreakpointEmpty() {
		gub.Msg("No breakpoints set")
		return
	}
	bpLen := len(gub.Breakpoints)
	if bpLen-gub.BrkptsDeleted == 0 {
		gub.Msg("No breakpoints.")
	}
	if len(args) > 2 {
		headerShown := false
		for _, num := range args[2:] {
			if bpNum, err := gub.GetInt(num,
				"breakpoint number", 0, bpLen-1); err == nil {
				if bp := gub.BreakpointFindById(bpNum); bp != nil {
					if !headerShown {
						gub.Section("Num Type          Disp Enb Where")
						headerShown = true
					}
					gub.Bpprint(*bp)
				} else {
					gub.Errmsg("Breakpoint %d not found.", bpNum)
				}
			}
		}
	} else {
		gub.Section("Num Type          Disp Enb Where")
		for _, bp := range gub.Breakpoints {
			if bp.Deleted {
				continue
			}
			gub.Bpprint(*bp)
		}
	}
}

func AliasCommand(args []string) {
	if len(args) == 1 {
		var names []string
		for k, _ := range gub.Aliases {
			names = append(names, k)
		}
		gub.Section("All aliases:")
		sort.Strings(names)
		opts := columnize.DefaultOptions()
		opts.DisplayWidth = gub.Maxwidth
		opts.LinePrefix = "  "
		mems := strings.TrimRight(columnize.Columnize(names, opts),
			"\n")
		gub.Msg(mems)
	} else {
		cmd := args[1]
		if info := gub.Cmds[cmd]; info != nil {
			if len(info.Aliases) > 0 {
				gub.Msg("Aliases for %s: %s",
					cmd, strings.Join(info.Aliases, ", "))
			} else {
				gub.Msg("No aliases for %s", cmd)
			}
		} else if realCmd := gub.Aliases[cmd]; realCmd != "" {
			gub.Msg("Alias %s is an alias for command %s", cmd, realCmd)

		} else {
			gub.Errmsg("Can't find command or alias %s", cmd)
		}
	}
}

// LocalsCommand implements the debugger command:
//    locals [*name*]
// which shows local variable info.
//
// See also "globals", "whatis", and "eval".
func LocalsCommand(args []string) {
	argc := len(args) - 1
	fr := gub.CurFrame()
	if argc == 0 {
		for i, _ := range fr.Locals() {
			gub.PrintLocal(fr, uint(i), false)
		}
		for reg, v := range fr.Reg2Var {
			gub.Msg("reg %s, var %s", reg, v)
		}
	} else {
		varname := args[1]
		if gub.PrintIfLocal(fr, varname, false) {
			return
		}
		// FIXME: This really shouldn't be needed.
		for i, v := range fr.Locals() {
			ssaVal := fr.Fn().Locals[i]
			if varname == ssaVal.Name() {
				gub.Msg("fixme %s %s: %s",
					varname, fr.Fn().Locals[i], interp.ToInspect(v, nil))
				break
			}
		}

	}
}

// InfoProgramSubcmd implements the debugger command:
//   info program
// This command prints information about the program including:
//    instruction number
//    block number
//    function number
//    stop event
//    source-code position
func InfoProgramSubcmd(args []string) {
	if gub.TraceEvent == ssa2.PROGRAM_TERMINATION {
		gub.Msg("program stop event: %s", ssa2.Event2Name[gub.TraceEvent])
		return
	}

	fr := gub.CurFrame()
	pc := fr.PC()
	gub.Msg("instruction number: %d", pc)
	block := gub.CurBlock()
	if block == nil {
		gub.Msg("unknown block")
	} else {
		gub.Msg("basic block: %d", block.Index)
		if block.Scope != nil {
			gub.Msg("scope: %d", block.Scope.ScopeId())
		} else {
			gub.Msg("unknown scope")
		}
	}

	gub.Msg("function: %s", fr.FnAndParamString())
	gub.Msg("program stop event: %s", ssa2.Event2Name[gub.TraceEvent])
	gub.Msg("position: %s", gub.CurFrame().PositionRange())
}

func InfoPCSubcmd(args []string) {
	fr := gub.CurFrame()
	pc := fr.PC()
	fn := fr.FnAndParamString()
	if block := gub.CurBlock(); block != nil {
		gub.Msg("instruction number: %d of block %d, function %s",
			pc, block.Index, fn)
	} else if pc == -2 {
		gub.Msg("instruction number: %d (at return), function %s", pc, fn)
	} else {
		gub.Msg("instruction number: %d, function %s", pc, fn)
	}
}

func InfoBlockSubcmd(args []string) {
	block := gub.CurBlock()
	// if block == nil && gub.Instr.Block() != nil {
	// 	block = gub.Instr.Block()
	// }
	if block == nil {
		gub.Msg("unknown block")
	} else {
		gub.Msg("basic block: %d", block.Index)
		if block.Scope != nil {
			gub.Msg("scope: %d", block.Scope.ScopeId())
		}
	}
}

// FormatCommand implements the debugger command: format
//
// format
//
// Formats AST and produces source text for function.
// FIXME: allow one to specify a function or package
func FormatCommand(args []string) {
	var syntax ast.Node
	var err error
	fr := gub.CurFrame()
	fn := fr.Fn()
	if len(args) > 1 {
		name := args[1]
		if name != "." {
			fn, err = gub.FuncLookup(name)
			if err != nil {
				gub.Errmsg(err.Error())
				return
			} else if fn == nil {
				gub.Errmsg("function '%s' not found", name)
				return
			}
		}
		syntax = fn.Syntax()
	} else {
		syntax = fn.Syntax()
		switch s := (*gub.Instr).(type) {
		case *ssa2.Trace:
			syntax = s.Syntax()
		}
	}
	// FIXME: Put this as a routine in parent gub and
	// use when showing locations
	if syntax != nil {
		gub.PrintSyntax(syntax, fn.Prog.Fset)
	} else {
		gub.Msg("Sorry, we don't have an AST for this")
	}
}

// AstCommand implements the debugger command: ast
//
// ast
//
// Prints AST for current function.
func AstCommand(args []string) {
	var syntax ast.Node
	var err error
	fr := gub.CurFrame()
	fn := fr.Fn()
	if len(args) > 1 {
		name := args[1]
		fn, err = gub.FuncLookup(name)
		if err != nil {
			gub.Errmsg(err.Error())
			return
		} else if fn == nil {
			gub.Errmsg("function '%s' not found", name)
			return
		} else {
			syntax = fn.Syntax()
		}
	} else {
		syntax = fn.Syntax()
		switch s := (*gub.Instr).(type) {
		case *ssa2.Trace:
			syntax = s.Syntax()
		}
	}
	if syntax != nil {
		ast.Print(fn.Prog.Fset, syntax)
		fmt.Println("")
	} else {
		gub.Msg("Sorry, we don't have an AST for this")
	}
}

func ContinueCommand(args []string) {
	for fr := gub.TopFrame(); fr != nil; fr = fr.Caller(0) {
		interp.SetStepOff(fr)
	}
	gub.InCmdLoop = false
	gub.Msg("Continuing...")
}

func LocationsCommand(args []string) {
	fn := gub.CurFrame().Fn()
	pkg := fn.Pkg
	for _, l := range pkg.Locs() {
		gub.Msg("\t%s", ssa2.FmtRange(fn, l.Pos(), l.EndP()))
	}
}

func InfoScopeSubcmd(args []string) {
	fr := gub.CurFrame()
	scope := fr.Scope()
	if scope == nil {
		gub.Errmsg("No scope recorded here")
		return
	}
	count := 0
	if len(args) == 3 {
		var err error
		count, err = gub.GetInt(args[2],
			"count", 0, gub.MAXSTACKSHOW)
		if err != nil {
			return
		}
	}

	typescope := scope.Scope
	for i := 0; i < count; i++ {
		typescope = typescope.Parent()
		if typescope == nil {
			gub.Errmsg("There are only %d nested scopes", i)
			return
		}
		scope = fr.Fn().Pkg.TypeScope2Scope[typescope]
		if scope == nil {
			gub.Errmsg("No parent scope; There are only %d nested scopes", i)
			return
		}
	}
	gub.Section("scope number %d", scope.ScopeId())
	gub.Msg("%s", typescope)
}

func InstructionCommand(args []string) {
	fr := gub.CurFrame()
	ic := uint64(fr.PC())
	if len(args) >= 2 {
		new_ic, ok := gub.GetUInt(args[1], "instruction number", 0,
			uint64(len(gub.CurFrame().Block().Instrs)))
		if ok == nil {
			ic = new_ic
		} else {
			gub.Errmsg("Expecting integer; got %s.", args[1])
			return
		}
		// if len(args) == 3 {
		// 	new_num, ok = strconv.Atoi(args[2])
		// 	if ok != nil {
		// 		gub.Errmsg("Expecting integer; got %s", args[2])
		// 		return
		// 	}
	}
	gub.DisasmInst(fr.Fn(), fr.Block().Index, ic)
	genericInstr := fr.Block().Instrs[ic]
	switch instr := genericInstr.(type) {
	case *ssa2.ChangeType:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.Convert:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.MakeInterface:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.ChangeInterface:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.Range:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.UnOp:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.Field:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
	case *ssa2.BinOp:
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.X), nil))
		gub.Msg("%s: %s", instr.X.Name(), gub.Deref2Str(fr.Get(instr.Y), nil))
	case *ssa2.Trace:
	default:
		gub.Msg("Don't know how to deal with %s yet", instr)
	}
}

// GlobalsCommand implements the debugger command:
//    globals [*name*]
// which shows global variable info.
//
// See also "locals", "whatis", and "eval".
func GlobalsCommand(args []string) {
	argc := len(args) - 1
	if argc == 0 {
		for k, v := range gub.CurFrame().I().Globals() {
			if v == nil {
				fmt.Printf("%s: nil\n")
			} else {
				// FIXME: figure out why reflect.lookupCache causes
				// an panic on a nil pointer or invalid address
				if fmt.Sprintf("%s", k) == "reflect.lookupCache" {
					continue
				}
				gub.Msg("%s: %s", k, interp.ToInspect(*v, &k))
			}
		}
	} else {
		// This doesn't work and I don't know how to fix it.
		for i := 1; i <= argc; i++ {
			vv := ssa2.NewConst(exact.MakeString(args[i]),
				types.Typ[types.String], token.NoPos, token.NoPos)
			// fmt.Println(vv, "vs", interp.ToInspect(vv))
			v, ok := gub.CurFrame().I().Globals()[vv]
			if ok {
				gub.Msg("%s: %s", vv, interp.ToInspect(*v, nil))
			}
		}

		// This is ugly, but I don't know how to turn a string into
		// a ssa2.Value.
		globals := make(map[string]*interp.Value)
		for k, v := range gub.CurFrame().I().Globals() {
			globals[fmt.Sprintf("%s", k)] = v
		}

		for i := 1; i <= argc; i++ {
			vv := args[i]
			v, ok := globals[vv]
			if ok {
				gub.Msg("%s: %s", vv, interp.ToInspect(*v, nil))
			}
		}
	}
}

// InfoArgsSubcmd implements the debugger command:
//    info args [arg-name]
// which shows argument variables of the current stack frame.
func InfoArgsSubcmd(args []string) {
	fr := gub.CurFrame()
	fn := fr.Fn()
	if len(args) == 2 {
		if len(fn.Params) == 0 {
			gub.Msg("Function `%s()' has no parameters", fn.Name())
			return
		}
		for i, p := range fn.Params {
			gub.Msg("%s %s", fn.Params[i], interp.ToInspect(fr.Env()[p], nil))
		}
	} else {
		varname := args[2]
		for i, p := range fn.Params {
			if varname == fn.Params[i].Name() {
				gub.Msg("%s %s", fn.Params[i], interp.ToInspect(fr.Env()[p], nil))
				break
			}
		}
	}
}

// DisableCommand implements the debugger command:
//    disable [bpnum1 ...]
// which disables a breakpoint by its breakpoint number.
//
// See also "enable", "delete", and "info break".
func DisableCommand(args []string) {
	for i := 1; i < len(args); i++ {
		msg := fmt.Sprintf("breakpoint number for argument %d", i)
		bpnum, err := gub.GetInt(args[i], msg, 0, len(gub.Breakpoints)-1)
		if err != nil {
			continue
		}
		if gub.BreakpointExists(bpnum) {
			if !gub.BreakpointIsEnabled(bpnum) {
				gub.Msg("Breakpoint %d is already disabled", bpnum)
				continue
			}
			if gub.BreakpointDisable(bpnum) {
				gub.Msg("Breakpoint %d disabled", bpnum)
			} else {
				gub.Errmsg("Trouble disabling breakpoint %d", bpnum)
			}
		} else {
			gub.Errmsg("Breakpoint %d doesn't exist", bpnum)
		}
	}
}

func SetHighlightSubcmd(args []string) {
	onoff := "on"
	if len(args) == 3 {
		onoff = args[2]
	}
	switch ParseOnOff(onoff) {
	case ONOFF_ON:
		if *gub.Highlight {
			gub.Errmsg("Highlight is already on")
		} else {
			gub.Msg("Setting highlight on")
			*gub.Highlight = true
		}
	case ONOFF_OFF:
		if !*gub.Highlight {
			gub.Errmsg("highight is already off")
		} else {
			gub.Msg("Setting highlight off")
			*gub.Highlight = false
		}
	case ONOFF_UNKNOWN:
		gub.Msg("Expecting 'on' or 'off', got '%s'; nothing done", onoff)
	}
}

func SetTraceSubcmd(args []string) {
	onoff := "on"
	if len(args) == 3 {
		onoff = args[2]
	}
	switch ParseOnOff(onoff) {
	case ONOFF_ON:
		if interp.InstTracing() {
			gub.Errmsg("Instruction tracing already on")
		} else {
			gub.Msg("Setting Instruction trace on")
			interp.SetInstTracing()
		}
	case ONOFF_OFF:
		if !interp.InstTracing() {
			gub.Errmsg("Instruction tracing already off")
		} else {
			gub.Msg("Setting Instruction trace off")
			interp.ClearInstTracing()
		}
	case ONOFF_UNKNOWN:
		gub.Errmsg("Expecting 'on' or 'off', got '%s'; nothing done", onoff)
	}
}

// QuitCommand implements the debugger command: quit
//
// quit [exit-code]
//
// Terminates program. If an exit code is given, that is the exit code
// for the program. Zero (normal termination) is used if no
// termintation code.
func QuitCommand(args []string) {
	rc := 0
	if len(args) == 2 {
		new_rc, ok := strconv.Atoi(args[1])
		if ok == nil {
			rc = new_rc
		} else {
			gub.Errmsg("Expecting integer return code; got %s. Ignoring",
				args[1])
		}
	}
	gub.Msg("gub: That's all folks...")

	// FIXME: determine under which conditions we've used term
	gnureadline.Rl_reset_terminal(gub.Term)

	os.Exit(rc)

}