A couple of quick tips

Since I have not had much time to blog recently, due to my dissertation, I felt bad.

So heres a couple of small tips:

Tracing Python Method Calls

I wanted to just trace an indented stack trace on the fly, as a debugging aid. This is what I devised:

pytrace_rx = re.compile(".*3c/phases/phase-.+/")

def pytrace(frame, event, arg):
        """
        this is for the -V flag (caps V)
        prints each python stack frame as it is opened.
        (slow)
        """

        if event == "call":
                full_path = frame.f_code.co_filename
                if pytrace_rx.match(full_path):

                        fn = full_path.split("/").pop()
                        sz = frame.f_code.co_stacksize

                        level = -1
                        tmp_frame = frame
                        while tmp_frame != None:
                                level = level + 1
                                tmp_frame = tmp_frame.f_back

                        pad = level * "  "
                        print(pad + "> " + fn + ": " + \
                                        frame.f_code.co_name)

sys.settrace(pytrace) # turn on tracing

Cool huh!

Drawing Parse Trees in LaTeX with QTree

\usepackage{qtree}
...
\Tree[.EXPR
        [.EXPR
                [.EXPR
                        [.number [.1 ]  ]
                ]
                [.OPER
                        [.+ ]
                ]
                [.number
                        [.2 ]
                ]
        ]
        [.OPER
                [.- ]
        ]
        [.number
                [.3 ]
        ]
]

Gives you:



Sweet!