add wrapscan option for cyclic search

Mentioned in #57.

comp.go

@@ -59,6 +59,9 @@ var (
 		"reverse",
 		"noreverse",
 		"reverse!",
+		"wrapscan",
+		"nowrapscan",
+		"wrapscan!",
 		"scrolloff",
 		"tabstop",
 		"filesep",

doc.go

@@ -70,6 +70,7 @@ The following options can be used to customize the behavior of lf:
     hidden     boolean  (default off)
     preview    boolean  (default on)
     reverse    boolean  (default off)
+    wrapscan   boolean  (default on)
     scrolloff  integer  (default 0)
     tabstop    integer  (default 8)
     filesep    string   (default ":")

docstring.go

@@ -74,6 +74,7 @@ The following options can be used to customize the behavior of lf:
     hidden     boolean  (default off)
     preview    boolean  (default on)
     reverse    boolean  (default off)
+    wrapscan   boolean  (default on)
     scrolloff  integer  (default 0)
     tabstop    integer  (default 8)
     filesep    string   (default ":")

eval.go

@@ -44,6 +44,12 @@ func (e *setExpr) eval(app *app, args []string) {
 	case "reverse!":
 		gOpts.reverse = !gOpts.reverse
 		app.nav.renew(app.nav.height)
+	case "wrapscan":
+		gOpts.wrapscan = true
+	case "nowrapscan":
+		gOpts.wrapscan = false
+	case "wrapscan!":
+		gOpts.wrapscan = !gOpts.wrapscan
 	case "scrolloff":
 		n, err := strconv.Atoi(e.val)
 		if err != nil {

nav.go

@@ -372,6 +372,7 @@ func (nav *nav) searchNext() {
 			return
 		}
 	}
+	if gOpts.wrapscan {
 		for i := 0; i < last.ind; i++ {
 			if strings.Contains(last.fi[i].Name(), nav.search) {
 				nav.up(last.ind - i)
@@ -379,6 +380,7 @@ func (nav *nav) searchNext() {
 			}
 		}
 	}
+}
 
 func (nav *nav) searchPrev() {
 	last := nav.currDir()
@@ -388,6 +390,7 @@ func (nav *nav) searchPrev() {
 			return
 		}
 	}
+	if gOpts.wrapscan {
 		for i := len(last.fi) - 1; i > last.ind; i-- {
 			if strings.Contains(last.fi[i].Name(), nav.search) {
 				nav.down(i - last.ind)
@@ -395,6 +398,7 @@ func (nav *nav) searchPrev() {
 			}
 		}
 	}
+}
 
 func (nav *nav) toggleMark(path string) {
 	if _, ok := nav.marks[path]; ok {

opts.go

@@ -7,6 +7,7 @@ var gOpts struct {
 	hidden    bool
 	preview   bool
 	reverse   bool
+	wrapscan  bool
 	scrolloff int
 	tabstop   int
 	filesep   string
@@ -27,6 +28,7 @@ func init() {
 	gOpts.hidden = false
 	gOpts.preview = true
 	gOpts.reverse = false
+	gOpts.wrapscan = true
 	gOpts.scrolloff = 0
 	gOpts.tabstop = 8
 	gOpts.filesep = ":"