[gnome-calculator] History follows preferences (fixes #105, fixes #168, fixes #159)

[Robert Roth <robertroth src gnome org>]

commit 3854b4937a112afee4b345f768d63370a0e1e3f9
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Jun 4 11:20:13 2020 +0300

    History follows preferences (fixes #105, fixes #168, fixes #159)

 lib/math-equation.vala |  5 +++--
 src/math-display.vala  |  2 ++
 src/math-history.vala  | 43 ++++++++++++++++++++++---------------------
 3 files changed, 27 insertions(+), 23 deletions(-)
---
diff --git a/lib/math-equation.vala b/lib/math-equation.vala
index 3d983ecc..46c91c08 100644
--- a/lib/math-equation.vala
+++ b/lib/math-equation.vala
@@ -118,6 +118,7 @@ public class MathEquation : Gtk.SourceBuffer
     }
 
     public signal void history_signal (string answer, Number number, int number_base, uint 
representation_base); /*signal to be emitted when a new calculation is tp be entered in history-view */
+    public signal void display_changed (Serializer serializer);
     private AngleUnit _angle_units;  /* Units for trigonometric functions */
     private NumberMode _number_mode;   /* ??? */
     private bool can_super_minus; /* true if entering minus can generate a superscript minus */
@@ -394,6 +395,8 @@ public class MathEquation : Gtk.SourceBuffer
 
         /* Add/remove thousands separators */
         reformat_separators ();
+
+        this.display_changed (serializer);
     }
 
     private MathEquationState get_current_state ()
@@ -795,8 +798,6 @@ public class MathEquation : Gtk.SourceBuffer
         /* Show the number in the user chosen format */
         var text = serializer.to_string (x);
 
-        if (representation_base != 0)
-            serializer.set_representation_base (number_base);
         this.history_signal (get_current_state ().expression, x, number_base, representation_base); /*emits 
signal to enter a new entry into history-view */
         set_text (text, -1);
         state.ans = x;
diff --git a/src/math-display.vala b/src/math-display.vala
index b08d53bf..a56a012c 100644
--- a/src/math-display.vala
+++ b/src/math-display.vala
@@ -38,6 +38,8 @@ public class MathDisplay : Gtk.Viewport
         history = new HistoryView ();
         history.answer_clicked.connect ((ans) => { insert_text (ans); });
         history.equation_clicked.connect ((eq) => { display_text (eq); });
+        history.set_serializer (equation.serializer);
+        _equation.display_changed.connect (history.set_serializer);
         main_box.add (history);
         main_box.show_all ();
 
diff --git a/src/math-history.vala b/src/math-history.vala
index f30d53af..5331217d 100644
--- a/src/math-history.vala
+++ b/src/math-history.vala
@@ -11,16 +11,13 @@
 [GtkTemplate (ui = "/org/gnome/calculator/history-view.ui")]
 public class HistoryView : Gtk.ScrolledWindow
 {
-    string? last_answer = null;
     string? last_equation = null;
 
-    Serializer serializer_four = new Serializer (DisplayFormat.AUTOMATIC, 10, 4);
-    Serializer serializer_nine = new Serializer (DisplayFormat.AUTOMATIC, 10, 9);
-
     [GtkChild]
     Gtk.ListBox listbox;
 
     private int _rows = 0;
+    private Serializer serializer;
     private int _current = 0;
     public int rows {get {return _rows;} }
     public int current {get {return _current;} set {_current = value.clamp(0, _rows); } }
@@ -50,19 +47,10 @@ public class HistoryView : Gtk.ScrolledWindow
     public void insert_entry (string equation, Number answer, int number_base, uint representation_base)
     {
 
-        serializer_four.set_base (number_base);
-        serializer_nine.set_base (number_base);
-
-        serializer_four.set_representation_base (representation_base);
-        serializer_nine.set_representation_base (representation_base);
-
-        var answer_nine_digits = serializer_nine.to_string (answer);
-        var answer_four_digits = serializer_four.to_string (answer);
-
-        if (last_answer == answer_nine_digits && last_equation == equation)
+        if (last_equation == equation)
             return;
 
-        var entry = new HistoryEntry (equation, answer_four_digits, answer_nine_digits);
+        var entry = new HistoryEntry (equation, answer, serializer);
 
         listbox.insert (entry, -1);
         entry.show ();
@@ -70,7 +58,6 @@ public class HistoryView : Gtk.ScrolledWindow
         entry.answer_clicked.connect ((ans) => { this.answer_clicked (ans); });
         entry.equation_clicked.connect ((eq) => { this.equation_clicked (eq); });
 
-        last_answer = answer_nine_digits;
         last_equation = equation;
         _rows++;
         current = rows - 1;
@@ -83,6 +70,12 @@ public class HistoryView : Gtk.ScrolledWindow
         _current = 0;
         listbox.foreach ((child) => { listbox.remove(child); });
     }
+
+    public void set_serializer (Serializer serializer)
+    {
+        this.serializer = serializer;
+        listbox.foreach ((child) => { ((HistoryEntry)child).redisplay (serializer); });
+    }
 }
 
 [GtkTemplate (ui = "/org/gnome/calculator/history-entry.ui")]
@@ -93,18 +86,26 @@ public class HistoryEntry : Gtk.ListBoxRow
     [GtkChild]
     public Gtk.Label answer_label;
 
+    private Number number;
+
     public signal void answer_clicked (string ans);
     public signal void equation_clicked (string equation);
 
     public HistoryEntry (string equation,
-                         string answer_four_digits,
-                         string answer_nine_digits)
+                         Number answer,
+                         Serializer serializer)
     {
+        this.number = answer;
+        equation_label.set_text (equation);
         equation_label.set_tooltip_text (equation);
-        answer_label.set_tooltip_text (answer_nine_digits);
+        redisplay (serializer);
+    }
 
-        equation_label.set_text (equation);
-        answer_label.set_text (answer_four_digits);
+    public void redisplay (Serializer serializer)
+    {
+        var answer = serializer.to_string (number);
+        answer_label.set_tooltip_text (answer);
+        answer_label.set_text (answer);
     }
 
     [GtkCallback]