1 files changed, 56 insertions, 2 deletions

diff --git a/gui/internal/ui/rules.go b/gui/internal/ui/rules.go
index 741f6b1..d582f1e 100644
--- a/gui/internal/ui/rules.go
+++ b/gui/internal/ui/rules.go
@@ -42,9 +42,12 @@ type rulesView struct {
 	testGo   *gtk.Button
 	out      *gtk.TextView
 
+	sub     *gtk.Notebook
+	forms   *formsView
 	rules   *model.Rules
 	pending glib.SourceHandle
 	quiet   bool // set while the view is being filled, so no check is armed
+	inSwap  bool // set while a sub-tab switch is being handled
 }
 
 func newRulesView(w *Window) *rulesView {
@@ -131,19 +134,37 @@ func newRulesView(w *Window) *rulesView {
 	right.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
 	right.Append(outScroll)
 
+	// Two ways to edit the same file: forms, and the text itself.
+	r.sub = gtk.NewNotebook()
+	r.forms = newFormsView(w, r)
+	r.sub.AppendPage(r.forms.root, gtk.NewLabel("Forms"))
+	r.sub.AppendPage(left, gtk.NewLabel("Text"))
+
 	panes := gtk.NewPaned(gtk.OrientationHorizontal)
-	panes.SetStartChild(left)
+	panes.SetStartChild(r.sub)
 	panes.SetEndChild(right)
 	panes.SetResizeStartChild(true)
 	panes.SetResizeEndChild(false)
 	panes.SetShrinkEndChild(false)
-	panes.SetPosition(620)
+	panes.SetPosition(820)
 	panes.SetVExpand(true)
 
 	r.root.Append(bar)
 	r.root.Append(gtk.NewSeparator(gtk.OrientationHorizontal))
 	r.root.Append(panes)
 
+	// Switching to Forms re-reads the text; text that does not parse keeps
+	// the Text tab until it is fixed (GUI design §5.2).
+	r.sub.ConnectSwitchPage(func(_ gtk.Widgetter, page uint) {
+		if page != 0 || r.inSwap || r.rules == nil {
+			return
+		}
+		if err := r.forms.reload(); err != nil {
+			r.setCheck("the text does not parse yet: " + err.Error())
+			r.showText()
+		}
+	})
+
 	r.buf.ConnectChanged(r.onChanged)
 	r.diags.ConnectRowSelected(func(row *gtk.ListBoxRow) {
 		if row != nil {
@@ -166,6 +187,34 @@ func newRulesView(w *Window) *rulesView {
 	return r
 }
 
+// formsOf is the forms of the text in the editor, for the Forms sub-tab.
+func (r *rulesView) formsOf() ([]model.Form, error) {
+	if r.rules == nil {
+		return nil, fmt.Errorf("no file is open")
+	}
+	r.rules.SetText(r.text())
+	return r.rules.Forms()
+}
+
+// setCheck writes one line in the bar where the check result goes.
+func (r *rulesView) setCheck(text string) { r.check.SetText(escape(text)) }
+
+// showText brings the Text sub-tab forward.
+func (r *rulesView) showText() {
+	r.inSwap = true
+	r.sub.SetCurrentPage(1)
+	r.inSwap = false
+}
+
+// textChangedByForm puts the model's text - just rewritten by a form edit -
+// in the view, and checks it.
+func (r *rulesView) textChangedByForm() {
+	r.quiet = true
+	r.buf.SetText(r.rules.Text)
+	r.quiet = false
+	r.runCheck()
+}
+
 // selectedName is the directory the picker names, "" when none is offered.
 func (r *rulesView) selectedName() string {
 	i := int(r.dirs.Selected())
@@ -190,6 +239,11 @@ func (r *rulesView) open(name string) {
 	}
 	r.rules = rules
 	r.setEditable(true)
+	defer func() {
+		if err := r.forms.reload(); err != nil {
+			r.forms.clearEditor("the text does not parse yet: " + err.Error())
+		}
+	}()
 	if root := r.w.dirRoot(name); root != "" {
 		r.testPath.SetText(xdg.Abbrev(root) + "/")
 	}