Object-oriented units of measurement

[Fabio Kon <kon*ime:usp:br>]

Oi,

Na última aula eu citei um artigo recente que apareceu  na OOPSLA'2004 
com um trabalho que estendeu a linguagem Java para comportar unidades de 
medidas.

O trabalho é o seguinte e pode ser baixado da Web (com máquinas com IP 
da USP):

http://portal.acm.org/citation.cfm?id=1028976.1029008


*Object-oriented units of measurement*
ABSTRACT

Programs that manipulate physical quantities typically represent these 
quantities as raw numbers corresponding to the quantities' measurements 
in particular units (e.g., a length represented as a number of meters). 
This approach eliminates the possibility of catching errors resulting 
from adding or comparing quantities expressed in different units (as in 
the Mars Climate Orbiter error [11]), and does not support the safe 
comparison and addition of quantities of the same dimension. We show how 
to formulate dimensions and units as classes in a nominally typed 
object-oriented language through the use of statically typed 
metaclasses. Our formulation allows both parametric and inheritance 
poly-morphism with respect to both dimension and unit types. It also 
allows for integration of encapsulated measurement systems, dynamic 
conversion factors, declarations of scales (including nonlinear scales) 
with defined zeros, and nonconstant exponents on dimension types. We 
also show how to encapsulate most of the "magic machinery" that handles 
the algebraic nature of dimensions and units in a single meta-class that 
allows us to treat select static types as generators of a free abelian 
group.



Note que um dos autores é o Guy L. Steele, Jr. que é um dos 4 criadores 
da linguagem Java.

[]s,
fabio.