Add reverse option (#55)

comp.go

@@ -56,6 +56,9 @@ var (
 		"preview",
 		"nopreview",
 		"preview!",
+		"reverse",
+		"noreverse",
+		"reverse!",
 		"scrolloff",
 		"tabstop",
 		"filesep",

doc.go

@@ -51,6 +51,7 @@ The following options can be used to customize the behavior of lf:
 	dirfirst   bool    (default on)
 	hidden     bool    (default off)
 	preview    bool    (default on)
+	reverse    bool    (default off)
 	scrolloff  int     (default 0)
 	tabstop    int     (default 8)
 	filesep    string  (default ":")

docstring.go

@@ -55,6 +55,7 @@ The following options can be used to customize the behavior of lf:
     dirfirst   bool    (default on)
     hidden     bool    (default off)
     preview    bool    (default on)
+    reverse    bool    (default off)
     scrolloff  int     (default 0)
     tabstop    int     (default 8)
     filesep    string  (default ":")

eval.go

@@ -35,6 +35,15 @@ func (e *setExpr) eval(app *app, args []string) {
 		gOpts.preview = false
 	case "preview!":
 		gOpts.preview = !gOpts.preview
+	case "reverse":
+		gOpts.reverse = true
+		app.nav.renew(app.nav.height)
+	case "noreverse":
+		gOpts.reverse = false
+		app.nav.renew(app.nav.height)
+	case "reverse!":
+		gOpts.reverse = !gOpts.reverse
+		app.nav.renew(app.nav.height)
 	case "scrolloff":
 		n, err := strconv.Atoi(e.val)
 		if err != nil {

nav.go

@@ -66,6 +66,12 @@ func getFilesSorted(path string) []*file {
 		log.Printf("unknown sorting type: %s", gOpts.sortby)
 	}
 
+	if gOpts.reverse {
+		for i, j := 0, len(fi)-1; i < j; i, j = i+1, j-1 {
+			fi[i], fi[j] = fi[j], fi[i]
+		}
+	}
+
 	if gOpts.dirfirst {
 		sortFilesStable(fi, func(i, j int) bool {
 			if fi[i].IsDir() == fi[j].IsDir() {

opts.go

@@ -6,6 +6,7 @@ var gOpts struct {
 	dirfirst  bool
 	hidden    bool
 	preview   bool
+	reverse   bool
 	scrolloff int
 	tabstop   int
 	filesep   string
@@ -24,6 +25,7 @@ func init() {
 	gOpts.dirfirst = true
 	gOpts.hidden = false
 	gOpts.preview = true
+	gOpts.reverse = false
 	gOpts.scrolloff = 0
 	gOpts.tabstop = 8
 	gOpts.filesep = ":"