A-M baby

Task/History-variables/Python/history-variables-1.py

@@ -0,0 +1,34 @@
+import sys
+
+HIST = {}
+
+def trace(frame, event, arg):
+    for name,val in frame.f_locals.items():
+        if name not in HIST:
+            HIST[name] = []
+        else:
+            if HIST[name][-1] is val:
+                continue
+        HIST[name].append(val)
+    return trace
+
+def undo(name):
+    HIST[name].pop(-1)
+    return HIST[name][-1]
+
+def main():
+    a = 10
+    a = 20
+
+    for i in range(5):
+        c = i
+
+    print "c:", c, "-> undo x3 ->",
+    c = undo('c')
+    c = undo('c')
+    c = undo('c')
+    print c
+    print 'HIST:', HIST
+
+sys.settrace(trace)
+main()

Task/History-variables/Python/history-variables-2.py

@@ -0,0 +1,2 @@
+c: 4 -> undo x3 -> 1
+HIST: {'a': [10, 20], 'i': [0, 1, 2, 3, 4], 'c': [0, 1], 'name': ['c']}