Better handling of arguments in Emacs mode.

Pressing sequences like 'esc---123' do now work:
- Repetition of minus signs is ignored.
- No esc prefix required for each number.

3 files changed, 35 insertions, 15 deletions

diff --git a/prompt_toolkit/key_binding/bindings/emacs.py b/prompt_toolkit/key_binding/bindings/emacs.py
index f173b4e2..e7a2e1bf 100644
--- a/prompt_toolkit/key_binding/bindings/emacs.py
+++ b/prompt_toolkit/key_binding/bindings/emacs.py
@@ -3,7 +3,7 @@ from __future__ import unicode_literals
 from prompt_toolkit.buffer import SelectionType, indent, unindent
 from prompt_toolkit.keys import Keys
 from prompt_toolkit.enums import IncrementalSearchDirection, SEARCH_BUFFER, SYSTEM_BUFFER
-from prompt_toolkit.filters import Always, Condition, EmacsMode, to_cli_filter, HasSelection, EmacsInsertMode, HasFocus
+from prompt_toolkit.filters import Always, Condition, EmacsMode, to_cli_filter, HasSelection, EmacsInsertMode, HasFocus, HasArg
 from prompt_toolkit.completion import CompleteEvent
 
 from .utils import create_handle_decorator
@@ -109,22 +109,32 @@ def load_emacs_bindings(registry, filter=Always()):
 
     def handle_digit(c):
         """
-        Handle Alt + digit in the `meta_digit` method.
+        Handle input of arguments.
+        The first number needs to be preceeded by escape.
         """
-        @handle(Keys.Escape, c)
+        @handle(c, filter=HasArg())
+        @handle(Keys.Escape, c, filter=~HasArg())
         def _(event):
             event.append_to_arg_count(c)
 
     for c in '0123456789':
         handle_digit(c)
 
-    @handle(Keys.Escape, '-')
+    @handle(Keys.Escape, '-', filter=~HasArg())
     def _(event):
         """
         """
         if event._arg is None:
             event.append_to_arg_count('-')
 
+    @handle('-', filter=Condition(lambda cli: cli.input_processor.arg == '-'))
+    def _(event):
+        """
+        When '-' is typed again, after exactly '-' has been given as an
+        argument, ignore this.
+        """
+        event.cli.input_processor.arg = '-'
+
     is_returnable = Condition(
         lambda cli: cli.current_buffer.accept_action.is_returnable)
 
diff --git a/prompt_toolkit/key_binding/input_processor.py b/prompt_toolkit/key_binding/input_processor.py
index d8fe4300..c23c76db 100644
--- a/prompt_toolkit/key_binding/input_processor.py
+++ b/prompt_toolkit/key_binding/input_processor.py
@@ -310,7 +310,16 @@ class KeyPressEvent(object):
         """
         Repetition argument.
         """
-        return self._arg or 1
+        if self._arg == '-':
+            return -1
+
+        result = int(self._arg or 1)
+
+        # Don't exceed a million.
+        if int(result) >= 1000000:
+            result = 1
+
+        return result
 
     def append_to_arg_count(self, data):
         """
@@ -321,15 +330,12 @@ class KeyPressEvent(object):
         assert data in '-0123456789'
         current = self._arg
 
-        if current is None:
-            if data == '-':
-                data = '-1'
-            result = int(data)
+        if data == '-':
+            assert current is None or current == '-'
+            result = data
+        elif current is None:
+            result = data
         else:
-            result = int("%s%s" % (current, data))
-
-        # Don't exceed a million.
-        if int(result) >= 1000000:
-            result = None
+            result = "%s%s" % (current, data)
 
         self.input_processor.arg = result
diff --git a/prompt_toolkit/layout/toolbars.py b/prompt_toolkit/layout/toolbars.py
index c5885b11..2e77c2fa 100644
--- a/prompt_toolkit/layout/toolbars.py
+++ b/prompt_toolkit/layout/toolbars.py
@@ -56,9 +56,13 @@ class SystemToolbar(ConditionalContainer):
 class ArgToolbarControl(TokenListControl):
     def __init__(self):
         def get_tokens(cli):
+            arg = cli.input_processor.arg
+            if arg == '-':
+                arg = '-1'
+
             return [
                 (Token.Toolbar.Arg, 'Repeat: '),
-                (Token.Toolbar.Arg.Text, str(cli.input_processor.arg)),
+                (Token.Toolbar.Arg.Text, arg),
             ]
 
         super(ArgToolbarControl, self).__init__(get_tokens)