# linedebug.py

# linedebug.py

def tr(msg=None): # tr()
    import inspect
    global prev_trace
    try:
        if prev_trace: pass
    except: prev_trace='#'
    trk = str(inspect.currentframe().f_back.f_lineno)
    # in case there is no trk_on variable
    try:
        # print '*',prev_trace,msg,'*'
        if trk_on == 1 and (prev_trace <> msg):
            print 'Line Number: ' + trk
            if msg!=None:
                print str(msg)
    except:
        # print 'error'
        pass
    prev_trace=msg
#trk_on = 1 <<< tracing unset

# * snippet as it is, should print --

tr()                #
tr("hello #1")      #
trk_on = 1
tr()                # Line Number: 28
tr("hello #2")      # Line Number: 29
                    # hello #2
trk_on = 0
tr()                #
tr("hello #3")      #
trk_on = 1
hello="hello #4"
tr(hello)           # Line Number: 36
                    # hello #4
hello=5
tr('')              # Line Number: 39 (+ empty newline)
tr(hello)           # Line Number: 40
                    # 5
tr(21)              # Line Number: 42
                    # 21
tr(21)              # (did not print a repeat)
                    #
#