Support Cancel/Abort DigitArgument

There was an exception with input like:

a Alt+1 Ctrl+C

CancelLine was clearing the buffer, but didn't reset _current.
That fixes the exception, but it still clears the input line
when called to terminate DigitArgument, so instead we do something
similar to how interactive history search is terminated.

Fixes #184

Author: lzybkr

PSReadLine/BasicEditing.cs

@@ -99,6 +99,7 @@ public static void CancelLine(ConsoleKeyInfo? key = null, object arg = null)
             var y = coordinates.Y + 1;
             _singleton.PlaceCursor(0, ref y);
             _singleton._buffer.Clear(); // Clear so we don't actually run the input
+            _singleton._current = 0; // If Render is called, _current must be correct.
             _singleton._currentHistoryIndex = _singleton._history.Count;
             _singleton._inputAccepted = true;
         }

PSReadLine/Changes.txt

@@ -16,6 +16,7 @@ Bug fixes:
 * ClearScreen now just clears the visible screen, not the entire buffer.
 * Fix exception on error input during rendering after certain keywords like process, begin, or end.
 * Fix exception after undo from menu completion
+* Support CancelLine (Ctrl+C) and Abort (Ctrl+G in emacs) to cancel DigitArgument
 
 New functions:
 * ValidateAndAcceptLine

PSReadLine/ReadLine.cs

@@ -677,34 +677,43 @@ public static void DigitArgument(ConsoleKeyInfo? key = null, object arg = null)
             {
                 var nextKey = ReadKey();
                 KeyHandler handler;
-                if (_singleton._dispatchTable.TryGetValue(nextKey, out handler) && handler.Action == DigitArgument)
+                if (_singleton._dispatchTable.TryGetValue(nextKey, out handler))
                 {
-                    if (nextKey.KeyChar == '-')
+                    if (handler.Action == DigitArgument)
                     {
-                        if (argBuffer[0] == '-')
+                        if (nextKey.KeyChar == '-')
                         {
-                            argBuffer.Remove(0, 1);
+                            if (argBuffer[0] == '-')
+                            {
+                                argBuffer.Remove(0, 1);
+                            }
+                            else
+                            {
+                                argBuffer.Insert(0, '-');
+                            }
+                            _singleton.Render(); // Render prompt
+                            continue;
                         }
-                        else
+
+                        if (nextKey.KeyChar >= '0' && nextKey.KeyChar <= '9')
                         {
-                            argBuffer.Insert(0, '-');
+                            if (!sawDigit && argBuffer.Length > 0)
+                            {
+                                // Buffer is either '-1' or '1' from one or more Alt+- keys
+                                // but no digits yet.  Remove the '1'.
+                                argBuffer.Length -= 1;
+                            }
+                            sawDigit = true;
+                            argBuffer.Append(nextKey.KeyChar);
+                            _singleton.Render(); // Render prompt
+                            continue;
                         }
-                        _singleton.Render(); // Render prompt
-                        continue;
                     }
-
-                    if (nextKey.KeyChar >= '0' && nextKey.KeyChar <= '9')
+                    else if (handler.Action == Abort ||
+                             handler.Action == CancelLine ||
+                             handler.Action == CopyOrCancelLine)
                     {
-                        if (!sawDigit && argBuffer.Length > 0)
-                        {
-                            // Buffer is either '-1' or '1' from one or more Alt+- keys
-                            // but no digits yet.  Remove the '1'.
-                            argBuffer.Length -= 1;
-                        }
-                        sawDigit = true;
-                        argBuffer.Append(nextKey.KeyChar);
-                        _singleton.Render(); // Render prompt
-                        continue;
+                        break;
                     }
                 }