Source code for mmf.utils.mdb

r"""Some debugging utilities"""
import sys

# Global variable to allow passing debug frame back to the user.
_LOCALS = [None]

try:
    import ipdb as pdb
    from ipdb import set_trace
except ImportError:
    import pdb
    def set_trace(frame=None):
        if frame is None:
            frame = sys._getframe().f_back
        pdb.Pdb().set_trace(frame=frame)
        
class MDBBreak(Exception):
    """MDB Breakout: Local variables in mmf.utils.mdb._LOCALS[0]:

    import mmf.utils.mdb; locals().update(mmf.utils.mdb._LOCALS[0])
    """
    def __init__(self):
        Exception.__init__(self, self.__doc__)
        

def mdb(trace=True):
    r"""Use in place of `import pdb;pdb.set_trace()`.

    When using the debugger, errors can crash the debugging session making it
    hard to continue.  This version stores the local variables in
    :attr:`_LOCALS` so that you work with these in the interpreter by doing
    something like

    import mmf.utils.mdb; locals().update(mmf.utils.mdb._LOCALS[0])
    """
    frame = sys._getframe()
    locals_ = frame.f_locals
    _LOCALS[0] = locals_
    if trace:
        set_trace(frame=frame.f_back)
    else:
        raise MDBBreak()

def breakout():
    mdb(trace=False)