[Python-Dev] PEP for adding a decimal type to Python

M.-A. Lemburg mal@lemburg.com
Fri, 27 Jul 2001 12:13:02 +0200

Just a suggestion which might also open the door for other numeric
type extensions to play along nicely:

Would it make sense to have an extensible registry of constructors 
for numeric types which maps number literal modifiers to constructors ?

I am thinking of

123L -> long("123")
123i -> int("123")
123.45f -> float("123.45")

The registry would map 'L' to long(), 'i' to int(), 'f' to float()
and be extensible in the sense, that e.g. an extension like
mxNumber could register its own mappings which would make 
the types defined in these extensions much more accessible
without having to path the interpreter. mxNumber for example could
then register 'r' to map to mx.Number.Rational() and a user could
then write 1/2r would map to 1 / mx.Number.Rational("2") and
generate a Rational number object for 1/2.

The registry would have to be made smart enough to seperate
integer notations from floating point ones and use two separate
default mapping for these, e.g. '<int>' -> int() and '<float>' ->

The advantage of such a mechanism would be that a user could
easily change the literal semantics at his/her taste.

Note that I don't think that we really need a separate interpreter
just to add decimals or rationals to the core. All that is needed
is some easy way to construct these number objects without too
much programming overhead (i.e. number of keys to hit ;-).

Marc-Andre Lemburg
CEO eGenix.com Software GmbH
Consulting & Company:                           http://www.egenix.com/
Python Software:                        http://www.lemburg.com/python/