New Edit.insert_test_result() method (nice for full-field validation)

1 files changed, 22 insertions, 0 deletions

diff --git a/urwid/widget.py b/urwid/widget.py
index cbdeb8b..89b5b18 100644
--- a/urwid/widget.py
+++ b/urwid/widget.py
@@ -952,6 +952,28 @@ class Edit(Text):
         self.set_edit_text(self._edit_text[:p] + text + 
             self._edit_text[p:])
         self.set_edit_pos(self.edit_pos + len(text))
+
+    def insert_text_result(self, ch):
+        """
+        Return result of insert_text(ch) without actually performing the
+        insertion.  Handy for pre-validation.
+        """
+
+        # if there's highlighted text, it'll get replaced by this character
+        if self.highlight:
+            start, stop = self.highlight
+            btext, etext = self.edit_text[:start], self.edit_text[stop:]
+            result_text =  btext + etext
+            result_pos = start
+        else:
+            result_text = self.edit_text
+            result_pos = self.edit_pos
+
+        if type(ch) == type(u""):
+            ch = ch.encode("utf-8")
+
+        result_text = result_text[:result_pos] + ch + result_text[result_pos:]
+        return (result_text, result_pos)
     
     def keypress(self, size, key):
         """