Allow splits to be created in either direction

This commit adds the `splitRight` and `splitBottom` options to allow
the user to pick which direction to split in.

This also means that a new split is no longer just appended to the list
of splits.

cmd/micro/settings.go

@@ -190,6 +190,8 @@ func DefaultGlobalSettings() map[string]interface{} {
 		"scrollspeed":  float64(2),
 		"scrollmargin": float64(3),
 		"softwrap":     false,
+		"splitRight":   true,
+		"splitBottom":  true,
 		"statusline":   true,
 		"syntax":       true,
 		"tabsize":      float64(4),
@@ -219,6 +221,8 @@ func DefaultLocalSettings() map[string]interface{} {
 		"scrollspeed":  float64(2),
 		"scrollmargin": float64(3),
 		"softwrap":     false,
+		"splitRight":   true,
+		"splitBottom":  true,
 		"statusline":   true,
 		"syntax":       true,
 		"tabsize":      float64(4),

cmd/micro/split_tree.go

@@ -12,8 +12,8 @@ const (
 
 // A Node on the split tree
 type Node interface {
-	VSplit(buf *Buffer)
-	HSplit(buf *Buffer)
+	VSplit(buf *Buffer, splitRight bool)
+	HSplit(buf *Buffer, splitBottom bool)
 	String() string
 }
 
@@ -52,16 +52,26 @@ type SplitTree struct {
 }
 
 // VSplit creates a vertical split
-func (l *LeafNode) VSplit(buf *Buffer) {
+func (l *LeafNode) VSplit(buf *Buffer, splitRight bool) {
 	tab := tabs[l.parent.tabNum]
 	if l.parent.kind == VerticalSplit {
 		newView := NewView(buf)
 		newView.TabNum = l.parent.tabNum
-		newView.Num = len(tab.views)
-		l.parent.children = append(l.parent.children, NewLeafNode(newView, l.parent))
 
-		tab.curView++
-		tab.views = append(tab.views, newView)
+		i := 0
+		if splitRight {
+			i = 1
+		}
+
+		l.parent.children = append(l.parent.children, nil)
+		copy(l.parent.children[l.view.Num+i+1:], l.parent.children[l.view.Num+i:])
+		l.parent.children[l.view.Num+i] = NewLeafNode(newView, l.parent)
+
+		tab.views = append(tab.views, nil)
+		copy(tab.views[l.view.Num+i+1:], tab.views[l.view.Num+i:])
+		tab.views[l.view.Num+i] = newView
+
+		tab.curView = l.view.Num + i
 	} else {
 		s := new(SplitTree)
 		s.kind = VerticalSplit
@@ -69,27 +79,47 @@ func (l *LeafNode) VSplit(buf *Buffer) {
 		s.tabNum = l.parent.tabNum
 		newView := NewView(buf)
 		newView.TabNum = l.parent.tabNum
-		newView.Num = len(tab.views)
-		s.children = []Node{l, NewLeafNode(newView, s)}
+		i := 0
+		if splitRight {
+			i = 1
+			s.children = []Node{l, NewLeafNode(newView, s)}
+		} else {
+			tab.curView = l.view.Num
+		}
 		l.parent.children[search(l.parent.children, l)] = s
 		l.parent = s
 
-		tab.curView++
-		tab.views = append(tab.views, newView)
+		tab.views = append(tab.views, nil)
+		copy(tab.views[l.view.Num+i+1:], tab.views[l.view.Num+i:])
+		tab.views[l.view.Num+i] = newView
+
+		tab.curView = l.view.Num + i
 	}
+
+	tab.Resize()
 }
 
 // HSplit creates a horizontal split
-func (l *LeafNode) HSplit(buf *Buffer) {
+func (l *LeafNode) HSplit(buf *Buffer, splitBottom bool) {
 	tab := tabs[l.parent.tabNum]
 	if l.parent.kind == HorizontalSplit {
 		newView := NewView(buf)
 		newView.TabNum = l.parent.tabNum
-		newView.Num = len(tab.views)
-		l.parent.children = append(l.parent.children, NewLeafNode(newView, l.parent))
 
-		tab.curView++
-		tab.views = append(tab.views, newView)
+		i := 0
+		if splitBottom {
+			i = 1
+		}
+
+		l.parent.children = append(l.parent.children, nil)
+		copy(l.parent.children[l.view.Num+i+1:], l.parent.children[l.view.Num+i:])
+		l.parent.children[l.view.Num+i] = NewLeafNode(newView, l.parent)
+
+		tab.views = append(tab.views, nil)
+		copy(tab.views[l.view.Num+i+1:], tab.views[l.view.Num+i:])
+		tab.views[l.view.Num+i] = newView
+
+		tab.curView = l.view.Num + i
 	} else {
 		s := new(SplitTree)
 		s.kind = HorizontalSplit
@@ -98,13 +128,24 @@ func (l *LeafNode) HSplit(buf *Buffer) {
 		newView := NewView(buf)
 		newView.TabNum = l.parent.tabNum
 		newView.Num = len(tab.views)
-		s.children = []Node{l, NewLeafNode(newView, s)}
+		i := 0
+		if splitBottom {
+			i = 1
+			s.children = []Node{l, NewLeafNode(newView, s)}
+		} else {
+			s.children = []Node{NewLeafNode(newView, s), l}
+		}
 		l.parent.children[search(l.parent.children, l)] = s
 		l.parent = s
 
-		tab.curView++
-		tab.views = append(tab.views, newView)
+		tab.views = append(tab.views, nil)
+		copy(tab.views[l.view.Num+i+1:], tab.views[l.view.Num+i:])
+		tab.views[l.view.Num+i] = newView
+
+		tab.curView = l.view.Num + i
 	}
+
+	tab.Resize()
 }
 
 // Delete deletes a split
@@ -253,10 +294,10 @@ func findView(haystack []*View, needle *View) int {
 }
 
 // VSplit is here just to make SplitTree fit the Node interface
-func (s *SplitTree) VSplit(buf *Buffer) {}
+func (s *SplitTree) VSplit(buf *Buffer, splitRight bool) {}
 
 // HSplit is here just to make SplitTree fit the Node interface
-func (s *SplitTree) HSplit(buf *Buffer) {}
+func (s *SplitTree) HSplit(buf *Buffer, splitBottom bool) {}
 
 func (s *SplitTree) String() string {
 	str := "["

cmd/micro/tab.go

@@ -64,6 +64,10 @@ func (t *Tab) Resize() {
 	}
 
 	t.tree.ResizeSplits()
+
+	for i, v := range t.views {
+		v.Num = i
+	}
 }
 
 // CurView returns the current view

cmd/micro/view.go

@@ -274,15 +274,13 @@ func (v *View) ReOpen() {
 
 // HSplit opens a horizontal split with the given buffer
 func (v *View) HSplit(buf *Buffer) bool {
-	v.splitNode.HSplit(buf)
-	tabs[v.TabNum].Resize()
+	v.splitNode.HSplit(buf, v.Buf.Settings["splitRight"].(bool))
 	return false
 }
 
 // VSplit opens a vertical split with the given buffer
 func (v *View) VSplit(buf *Buffer) bool {
-	v.splitNode.VSplit(buf)
-	tabs[v.TabNum].Resize()
+	v.splitNode.VSplit(buf, v.Buf.Settings["splitBottom"].(bool))
 	return false
 }
 

runtime/help/options.md

@@ -101,6 +101,16 @@ Here are the options that you can set:
 
     default value: `off`
 
+* `splitRight`: when a vertical split is created, should it be created to the right of
+   the current split?
+
+    default value: `on`
+
+* `splitRight`: when a horizontal split is created, should it be created below the
+   current split?
+
+    default value: `on`
+
 * `autosave`: micro will save the buffer every 8 seconds automatically.
    Micro also will automatically save and quit when you exit without asking.
    Be careful when using this feature, because you might accidentally save a file,