subcommand.py

# A Sub command dispatcher for methods in Python
# Thanks to dectools: http://pypi.python.org/pypi/dectools
#
# Use Case: You have a function that takes 1 + N parameters. The first
# parameter you would use as a switch statement (in C), or as a key in
# a Dictionary (in Python) to figure out another function to send
# the other N args to.
# 
# for example, command line parsers:
#    def handle_commands():
#        command = sys.argv[1]
#        params = sys.argv[1:]
#        dispatchDict = dict("hello": say_hello)
#        dispatchDict[command](params)
#
#   BORING!!
#
# With @subcommand_dispatch we can define functions based on our expected user input
# triggered off the name of the function the calling code THOUGHT it was calling
#
#  def handle_commands_hello(args):
#      print "hello!"
#
#  @ subcommand_dispatch
#  def handle_commands(name, args):
#      pass
#
# Which is easy!

from dectools import dectools

@dectools.make_call_instead
def subcommand_dispatch(function, args, kwargs):
    #print "called for %s" % function.__name__
    fname = function.__name__
    name, other = args
    try:
        fObj = globals()[ fname +"_" +args[0] ]
        fObj( other )
    except KeyError:
        print "could not do '%s %s %s' (did you spell it right?)" % (  fname, args[0], " ".join( args[1:] )  )
        #print "do paver help %s to get help"

# Use it like:

def dispatcher_hello(option):
    print "hello, " + option
    
@subcommand_dispatch
def dispatcher(option1, option2):
    pass

print "starting the magic of subcommand_dispatch"
print "------------------------------------------"
dispatcher("hello", "bob")
print "------------------------------------------"
print "ok, all done!"