Thanks. The game context is I would like to write a scripting language on
top of pygame/python for my game.
----- Original Message -----
From: "Lenard Lindstrom" <le...@telus.net>
To: <pygame-users@seul.org>
Sent: Wednesday, December 31, 2008 1:32 PM
Subject: Re: [pygame] @
This is getting off topic for a game oriented mailing list, but many of
the things other languages use macro to accomplish come naturally to
Python because it is dynamically typed. For instance the function:
def do_add(x, y):
return x + y
will work with integers, floats, complex numbers, lists and any other
class that defines an addition operation. Python has many hooks that take
callback functions. These can redefine the way imports work, for instance.
Also, metaclasses allow one to change how class declarations work. So
though there is no mechanism to add new syntax and constructs to the
Python language, there are plenty of ways to change how the existing
syntax works.
Lenard
Noah Kantrowitz wrote:
Python has no such system. Boo is a python-like language that supports
hygienic macros.
--Noah
On Dec 31, 2008, at 1:20 PM, Lin Parkh wrote:
While we're on this kind of topic what is the best approach in python to
creating code macros? That is ability to write a higher level language
(or script) which translates down into python? Decorators look like they
would be part of that story. Is that the best way or is their a more
general way?
Thanks,
Lin
p.s. I used to write code macros in LISP... context I am coming from.
----- Original Message ----- From: "Michael George"
<mdgeo...@cs.cornell.edu>
To: <pygame-users@seul.org>
Sent: Wednesday, December 31, 2008 9:56 AM
Subject: Re: [pygame] @
Michael Phipps wrote:
Yanom -
A decorator is a method that takes another method as a parameter so
that it can do something. It is usually used for aspect oriented
programming.
For example:
def logThisMethodCall(methodCall)
# Do some logging here
@logThisMethodCall
def myMethod(a,b,c)
# do Somthing in here
Now, whenever you call "myMethod", logThisMethodCall gets called
first, with the invocation of myMethod passed into it. You can use it
for logging, security (i.e. does this person have permission to be
calling this), etc.
Michael
This isn't quite right. logThisMethodCall doesn't get called when you
call myMethod, but when you _define_ myMethod. So to fix this example:
def logThisMethodCall(methodCall):
def result(a,b,c):
# do some logging here
methodCall(a,b,c)
return result
@logThisMethodCall
def myMethod(a,b,c):
# do something here
When you define myMethod, logThisMethodCall is called to create a
replacement function for myMethod. it returns a new function "result"
which gets called instead of the original myMethod whenever someone
calls myMethod. result does some logging and then calls the orginal
myMethod.
--
Lenard Lindstrom
<le...@telus.net>