Tracing function calls using Python decorators

Contents Introduction A less invasive way Decorators Improving echo Wider application Work in progress Source Code Credits @ end Introduction Let’s suppose you want to trace calls to a function. That is, every time the function gets called, you want to print out its name and the values of any arguments passed by the caller. To provide a concrete example, here’s a function which calculates the dot product of two vectors. def dot(v, w): """Calculate the dot product of two vectors. Example: >>> dot((1, 2, 3), (3, 2, 1)) 10 """ return sum(vv * ww for vv, ww in zip(v, w)) To trace calls to the function you could just edit it and insert a print statement. def dot(v, w): print "dot(v=%r, w=%r)" % (v, w&#...