On Aug 1, 9:08 am, Paul McGuire <[EMAIL PROTECTED]> wrote:
> On Jul 31, 3:28 pm, Maximus Decimus <[EMAIL PROTECTED]> wrote:
>
>
>
> > I am using python v2.5 and I am an amateur working on python. I am
> > extending python for my research work and would like some help and
> > guidance w.r.t this matter from you experienced python developers.
>
> > II want to add some more KEYWORDS and DATATYPES into the python script
> > apart from the existing ones.
>
> Vishak -
>
> Let me echo the sentiments of the other posters who replied to your
> message. It is *very* unusual for a new Python user to begin their
> Pythonic journey by modifying the Python interpreter to add new
> keywords and datatypes. Python is designed to be a very flexible and
> extensible language just as it is.
>
> Since you are familiar with C, your question strikes those of us on
> this group as one who would write "I'm just learning C and I would
> like to modify the core library to add some new functions for my
> research." And all the readers on comp.lang.c scratch their heads,
> thinking "Huh? Why doesn't this guy just write the functions in his
> own program, the way the language was designed for him to do in the
> first place?"
>
> Now maybe your research is in the field of language design, and has
> something to do with the relative ease/difficulty of modifying
> computer languages. Then it would make sense for you to dive right in
> to learning how to modify Python's compiler.
>
> But if your research was in just about any other field (from finite
> elements analysis to genetic programming to genetics to simulations to
> process control to whatever), DON'T start by modifying Python - start
> by LEARNING Python.
>
> When a new datatype is required in a Python program, then the
> programmer writes a class to implement this datatype. The class
> itself is written in Python, but it can be used just like any built-in
> datatype. For instance, here is a new datatype I just thought up - a
> Box that can hold up to 'n' objects.
>
> class Box(object):
> def __init__(self,n):
> self.capacity = n
> self.contents = []
>
> def add(self,other):
> if len(self.contents) < self.capacity:
> self.contents.append( other )
> else:
> raise ValueError("can't add any more to this Box")
>
> def __iadd__(self,other):
> self.add(other)
> return self
>
> box = Box(3)
>
> # add stuff to the box until it overflows
> while(True):
> box += object()
>
> Voila! I created a new datatype, Box, and even added support for it
> to understand how to use the '+=' operator so that adding objects to
> the Box looks like an addition statement. All without modifying
> Python itself. (Here's an exercise - extend this example so that the
> Box has a limited capacity in the *weight* of the added objects, as
> well as in the number of objects.)
>
> This is the basic way that one extends Python with their own new
> datatypes and methods. New keywords are a little rarer, but really,
> start by just adding methods, like the add method above. Python users
> around the world develop a wide range of applications and programs
> using just these techniques, and never touch the Python compiler
> itself.
>
> And here is a case you'd like to avoid. Let's say you start by
> learning how to modify Python because you need a general-purpose
> container for things. You spend two weeks learning how to do this,
> getting your code mostly debugged, and then you post to
> comp.lang.python your proud achievement. Immediately the replies come
> back, "Congratulations, newbie, you just reinvented the built-in list
> type." Without LEARNING Python, you wont know what is already
> provided in the language.
>
> So, in general this is a helpful group, and it is possible that you DO
> need to learn how to add datatypes and keywords to Python as your
> first objective. We're not trying to pry, but give us a bit more
> detail. Someone might even rough out for you what one of your new
> datatypes might look like. So pray, tell us what sort of specialized
> datatypes and keywords do you think you need to add, and we'll try to
> point you in one or more directions.
>
> -- Paul
On Aug 1, 9:08 am, Paul McGuire <[EMAIL PROTECTED]> wrote:
> On Jul 31, 3:28 pm, Maximus Decimus <[EMAIL PROTECTED]> wrote:
>
>
>
> > I am using python v2.5 and I am an amateur working on python. I am
> > extending python for my research work and would like some help and
> >
