wxyarv wrote:

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Whenever my module A needs to pass a lot of data to module B, I find myself making a factory function in module B for creating the datastructures

def my_factory_function(a, b, c): # input checking res.a = a res.b = b res.c = c return res

I believe this is fairly common.

Since the fields are already defined in the function signature, I'd prefer to not repeat myself and write something like this:

def my_factory_function(a, b, c): args = locals() # input checking return namedtuple('MyTypeName', args)

This would perceivably be possible, if locals() returned an OrderedDict and an appropriate namedtuple factory function was added.

related discussion is in: http://kbyanc.blogspot.com/2007/07/python-aggregating-function-arguments.htm... http://code.activestate.com/recipes/500261/

Does this seem familiar or useful to anyone besides me? in current syntax, res.a = a is not allowed, if res is a dict, the right syntax is res['a'] = a. in some languages, res.a equals res['a'], but not in python. (and isn't possible in Python, because there are many disadvantage to make this.). so, if you need put arguments into a dict, you can do this: def my_factory_function(**arg): # input check return arg arg is a dict. and, if res is a class, you are setting the attribute of res. you can also: def my_factory_function(**arg): # input check res.__dict__.update(arg) return res a named tuple is just a dict (I think :-)

Right. I probably didn't express myself too well. The current recipe for 'structs' is here http://docs.python.org/tutorial/classes.html#odds-and-ends make an empty class, and assign fields as necessary. I prefer using factory functions, since I then I can define in a single place, what the 'struct' is supposed to contain, and the function signature will conveniently raise errors if I've made changes in module B, but not A. The same boilerplate code is also in all normal class init methods, you list the stuff once in the __init__ method arguments, then you list them again when you assign them, and I'm just wondering why do I have to repeat myself. As for named tuples, I quote http://docs.python.org/library/collections.html#namedtuple-factory-function-... "Named tuple instances do not have per-instance dictionaries, so they are lightweight and require no more memory than regular tuples." -- Eero Nevalainen

wxyarv wrote:

...

...

Whenever my module A needs to pass a lot of data to module B, I find myself making a factory function in module B for creating the datastructures

def my_factory_function(a, b, c): # input checking res.a = a res.b = b res.c = c return res

I believe this is fairly common.

Since the fields are already defined in the function signature, I'd prefer to not repeat myself and write something like this:

def my_factory_function(a, b, c): args = locals() # input checking return namedtuple('MyTypeName', args)

This would perceivably be possible, if locals() returned an OrderedDict and an appropriate namedtuple factory function was added.

related discussion is in: http://kbyanc.blogspot.com/2007/07/python-aggregating-function-arguments.htm... http://code.activestate.com/recipes/500261/

Does this seem familiar or useful to anyone besides me? in current syntax, res.a = a is not allowed, if res is a dict, the right syntax is res['a'] = a. in some languages, res.a equals res['a'], but not in python. (and isn't possible in Python, because there are many disadvantage to make this.). so, if you need put arguments into a dict, you can do this: def my_factory_function(**arg): # input check return arg arg is a dict. and, if res is a class, you are setting the attribute of res. you can also: def my_factory_function(**arg): # input check res.__dict__.update(arg) return res a named tuple is just a dict (I think :-)

Right. I probably didn't express myself too well. The current recipe for 'structs' is here http://docs.python.org/tutorial/classes.html#odds-and-ends make an empty class, and assign fields as necessary. I prefer using factory functions, since I then I can define in a single place, what the 'struct' is supposed to contain, and the function signature will conveniently raise errors if I've made changes in module B, but not A. The same boilerplate code is also in all normal class init methods, you list the stuff once in the __init__ method arguments, then you list them again when you assign them, and I'm just wondering why do I have to repeat myself. As for named tuples, I quote http://docs.python.org/library/collections.html#namedtuple-factory-function-... "Named tuple instances do not have per-instance dictionaries, so they are lightweight and require no more memory than regular tuples." -- Eero Nevalainen