A simple tool to see branch tracing arcs

Author: nedbat

lab/branch_trace.py

@@ -0,0 +1,17 @@
+import sys
+
+pairs = set()
+last = -1
+
+def trace(frame, event, arg):
+    global last
+    if event == "line":
+        this = frame.f_lineno
+        pairs.add((last, this))
+        last = this
+    return trace
+
+code = open(sys.argv[1]).read()
+sys.settrace(trace)
+exec(code)
+print(sorted(pairs))