make keyboard completions work

1. When adding a button to flowbox, the flowbox widget interposes a
flowboxchild between the two, which can receive events and so becomes
part of the tab order. this is why our buttons weren't getting
activated - they weren't focused even though they looked focused.  So,
use labels instead of buttons for completions

2. For some reason I don't understand, flowboxchild widgets receive
:activate *only* on keyboard activation. So instead of using it,
we connect to :child-activated on the flowbox.

3. Setting widget:on_foo *adds* a handler to the widget instead of
replacing what was previously there. There is no nice way to remove
handlers from a widget either. Because we need a new
on_child_activated handler every time the completions change,
the only way I can see to achieve this is to create the flowbox
afresh on each keystroke instead of creating it once when the
frame is created

command.fnl

@@ -20,7 +20,7 @@
 (fn completion [{: widget : text : value }]
   (let [value (or value (assert text "must have text"))]
     {
-     :widget (or widget (Gtk.Button { :label text }))
+     :widget (or widget (Gtk.Label { :label text }))
      : text
      : value
      }))
@@ -52,7 +52,7 @@
                (icollect [v (_G.history:find-distinct term)]
                  (let [label (.. v.url " " (or v.title ""))]
                    (completion { :text v.url
-                                 :widget (Gtk.Button { : label })
+                                 :widget (Gtk.Label { : label })
                                  :value v.url
                                  })))
                [])]
@@ -147,6 +147,8 @@
   (if (not result.active)
       (completions-widget:hide))
   (set entry.text (or result.default result.error ""))
+  (if result.active (entry:grab_focus))
+
   (when widget.parent
     (widget.parent:set_visible_child_name
      (if result.active "commander" "echo-area"))))
@@ -155,14 +157,29 @@
   (let [parent self.completions-widget
         set-completions
         (fn [completions]
-          (parent:foreach #(parent:remove $1))
-          (each [_ c (pairs completions)]
-            (parent:add
-             (doto c.widget
-               (tset :on_clicked
-                     #(update-widget-state
-                       self
-                       (self:on-input-finished c.text))))))
+          (let [flowbox (Gtk.FlowBox {
+                                      :activate_on_single_click true
+                                      :selection_mode Gtk.SelectionMode.SINGLE
+                                      })
+                ;; I don't know why, but the flowboxchild activate signal
+                ;; is working only for keyboard activation not for
+                ;; clicking.  So instead of using it we connect to
+                ;; child_activated, and use kids-map to find out which
+                ;; child it was
+                kids-map {}]
+            (parent:foreach #(parent:remove $1)) ; expect only 1 direct child
+            (each [_ c (pairs completions)]
+              (let [fbc (Gtk.FlowBoxChild)]
+                (tset kids-map fbc c.text)
+                (fbc:add c.widget)
+                (flowbox:add fbc)))
+            (tset flowbox :on_child_activated
+                  (fn [_self child]
+                    (match (. kids-map child)
+                      text (update-widget-state
+                            self
+                            (self:on-input-finished text)))))
+            (parent:add flowbox))
           (parent:show_all))]
     (match self.state
       {:command c :this-param param-name}
@@ -210,7 +227,7 @@
         prompt (Gtk.Label { :label ""})
         box (Gtk.Box { :orientation Gtk.Orientation.VERTICAL })
         hbox (Gtk.Box { :orientation Gtk.Orientation.HORIZONTAL })
-        completions (Gtk.FlowBox)
+        completions (Gtk.Box { :orientation Gtk.Orientation.VERTICAL })
         self {
               :state default-state
               : activate

musing.md

@@ -66,18 +66,20 @@ focus from entry to step through the completions then RET activates
 * [done] back binding
 * [done] save url history, use it in completions
 * [done] autocomplete command name
+* [done] keyboard navigation of completions
 
 * custom rendering for completions (e.g. buffer thumbnails)
 * less ugly default completions rendering
 * buffer name is often going to be useless. find buffers by url/title
    still need some 1:1 mapping between the buffer object and
    a text-representable form of same
-* bind event to echo-area click, ideally dependent on what's being shown
-  in there
+* bind event to echo-area click, ideally dependent on what's being shown in there
 * in general, can we bind commands to widget events?
 * command to create new buffer
-* keyboard navigation of completions
 
 * suppress "Return is undefined" message after a command executes
 
 ----
+
+can we increase the testability? e.g. for command processing,
+define a command, feed in some keystrokes,

search.fnl

@@ -35,7 +35,7 @@
         (completion {
                      :text keyword
                      :value keyword
-                     :widget (Gtk.Button { :label name })
+                     :widget (Gtk.Label { :label name })
                      }))))