Handle newlines better in URWIDRepl.echo (closes bpython#150).

marienz · marienz · commit 63ded48cf056 · 2010-09-19T14:52:15.000+02:00
We were incorrectly using multiple lines for each call to echo even if
the displayed string did not end in a newline. This fixes it by
reusing the last urwid Text widget in that case, adding an implicit
newline on prompt.
diff --git a/bpython/urwid.py b/bpython/urwid.py
@@ -444,20 +444,28 @@ def __init__(self, event_loop, palette, interpreter, config):
 
         self.edits = []
         self.edit = None
+        self.current_output = None
         self._completion_update_suppressed = False
 
     # Subclasses of Repl need to implement echo, current_line, cw
-    def echo(self, s):
-        s = s.rstrip('\n')
+    def echo(self, orig_s):
+        s = orig_s.rstrip('\n')
         if s:
-            text = urwid.Text(('output', s))
-            if self.edit is None:
-                self.listbox.body.append(text)
+            if self.current_output is None:
+                self.current_output = urwid.Text(('output', s))
+                if self.edit is None:
+                    self.listbox.body.append(self.current_output)
+                else:
+                    self.listbox.body.insert(-1, self.current_output)
+                    # The edit widget should be focused and *stay* focused.
+                    # XXX TODO: make sure the cursor stays in the same spot.
+                    self.listbox.set_focus(len(self.listbox.body) - 1)
             else:
-                self.listbox.body.insert(-1, text)
-                # The edit widget should be focused and *stay* focused.
-                # XXX TODO: make sure the cursor stays in the same spot.
-                self.listbox.set_focus(len(self.listbox.body) - 1)
+                # XXX this assumes this all has "output" markup applied.
+                self.current_output.set_text(
+                    ('output', self.current_output.text + s))
+        if orig_s.endswith('\n'):
+            self.current_output = None
         # TODO: maybe do the redraw after a short delay
         # (for performance)
         self.main_loop.draw_screen()
@@ -708,6 +716,10 @@ def keyboard_interrupt(self):
         self.echo('KeyboardInterrupt')
 
     def prompt(self, more):
+        # Clear current output here, or output resulting from the
+        # current prompt run will end up appended to the edit widget
+        # sitting above this prompt:
+        self.current_output = None
         # XXX is this the right place?
         self.rl_history.reset()
         # XXX what is s_hist?
