Initial checking of Tk-based Python IDE.

Features: text editor with syntax coloring and undo;
subclassed into interactive Python shell which adds history.

Tools/idle/IdleHistory.py

@@ -0,0 +1,73 @@
+import string
+
+class History:
+    
+    def __init__(self, text):
+        self.text = text
+        self.history = []
+        self.history_prefix = None
+        self.history_pointer = None
+        text.bind("<<history-previous>>", self.history_prev)
+        text.bind("<<history-next>>", self.history_next)
+
+    def history_next(self, event):
+        self.history_do(0)
+        return "break"
+
+    def history_prev(self, event):
+        self.history_do(1)
+        return "break"
+
+    def history_do(self, reverse):
+        nhist = len(self.history)
+        pointer = self.history_pointer
+        prefix = self.history_prefix
+        if pointer is not None and prefix is not None:
+            if self.text.compare("insert", "!=", "end-1c") or \
+               self.text.get("iomark", "end-1c") != self.history[pointer]:
+                pointer = prefix = None
+        if pointer is None or prefix is None:
+            prefix = self.text.get("iomark", "end-1c")
+            if reverse:
+                pointer = nhist
+            else:
+                pointer = -1
+        nprefix = len(prefix)
+        while 1:
+            if reverse:
+                pointer = pointer - 1
+            else:
+                pointer = pointer + 1
+            if pointer < 0 or pointer >= nhist:
+                self.text.bell()
+                if self.text.get("iomark", "end-1c") != prefix:
+                    self.text.delete("iomark", "end-1c")
+                    self.text.insert("iomark", prefix)
+                pointer = prefix = None
+                break
+            item = self.history[pointer]
+            if item[:nprefix] == prefix and len(item) > nprefix:
+                self.text.delete("iomark", "end-1c")
+                self.text.insert("iomark", item)
+                break
+        self.text.mark_set("insert", "end-1c")
+        self.text.see("insert")
+        self.text.tag_remove("sel", "1.0", "end")
+        self.history_pointer = pointer
+        self.history_prefix = prefix
+
+    def history_store(self, source):
+        source = string.strip(source)
+        if len(source) > 2:
+            self.history.append(source)
+        self.history_pointer = None
+        self.history_prefix = None
+
+    def recall(self, s):
+        s = string.strip(s)
+        self.text.tag_remove("sel", "1.0", "end")
+        self.text.delete("iomark", "end-1c")
+        self.text.mark_set("insert", "end-1c")
+        self.text.insert("insert", s)
+        self.text.see("insert")
+