first prototype

mathentry.py

@@ -0,0 +1,87 @@
+import wx
+from eval import arithmetic_eval
+from utils import typename
+
+
+class MathEntry(wx.TextCtrl):
+
+    def __init__(self, *args, value="", **kwargs):
+        if "style" in kwargs:
+            kwargs["style"] |= wx.TE_PROCESS_ENTER
+        else:
+            kwargs["style"] = wx.TE_PROCESS_ENTER
+
+        self.value_type = type(value)
+        value = str(value)
+        wx.TextCtrl.__init__(self, *args, value=value, **kwargs)
+
+        self._alarm = False
+        self._last_good_value = self.GetValue()
+
+        self.Bind(wx.EVT_TEXT_ENTER, self.on_enter)
+        self.Bind(wx.EVT_KEY_UP, self.on_escape)
+
+
+    def GetValue(self):
+        val = super().GetValue()
+        try:
+            val = self.value_type(val)
+        except ValueError:
+            pass
+        return val
+
+
+    def SetValue(self, val):
+        val = str(val)
+        super().SetValue(val)
+
+
+    def on_enter(self, event):
+        val = super().GetValue()
+
+        self._unset_alarm()
+
+        try:
+            val = arithmetic_eval(val)
+            self.value_type = type(val)
+        except SyntaxError as e:
+            en = typename(e)
+            msg = e.args[0]
+            msg = f"{en}: {msg}"
+            self._set_alarm(msg)
+            self.SetInsertionPoint(e.offset)
+        except Exception as e:
+            en = typename(e)
+            msg = f"{en}: {e}"
+            self._set_alarm(msg)
+            self.SetInsertionPointEnd()
+        else:
+            self.SetValue(val)
+            self._last_good_value = val
+
+        event.Skip()
+
+
+    def on_escape(self, event):
+        code = event.GetKeyCode()
+        if code != wx.WXK_ESCAPE:
+            event.Skip()
+            return
+
+        if self._alarm:
+            self.SetValue(self._last_good_value)
+            self._unset_alarm()
+
+
+    def _set_alarm(self, msg):
+        self._alarm = True
+        self.SetToolTip(msg)
+        self.SetForegroundColour(wx.RED)
+
+    def _unset_alarm(self):
+        self._alarm = False
+        self.SetToolTip(None)
+        self.SetForegroundColour(wx.NullColour)
+
+
+