Hi, Matthias:
Yes, you're right about the "sum" types of the domain and range of
functions. A small remark below (just to clarify myself too...)
On 31/08/13 20:36, Matthias Felleisen wrote:
On Aug 31, 2013, at 2:19 PM, Diego Sevilla Ruiz wrote:
The example you give for C, you're right, it is not appropriate for C because C
has a (lax) static type system.
Let's call it what it is: unsound. Let's also agree that C's type system is so
impoverished that it is simply useless to talk about in such contexts.
Completely agree.
You know, Scheme, Racket, they are dynamically typed languages: the type of the
elements can vary at run time, so there are a lot of situations in which the
type itself of the element changes.
Racket's values cannot change 'type' at run-time. In principle, we shouldn't
use the word 'type' for dynamic concepts -- types are a static discipline --
but when you are given a value, any predicate you apply to it will always
return the same answer over the course of the entire execution.
I was not refering to values, but to variables. The term "dynamically
typed" refer (to my knowledge) to languages like Scheme and Racket whose
variables can change the type of the value they hold or refer during the
execution.
Regards,
diego.
--
Diego Sevilla Ruiz -- http://ditec.um.es/~dsevilla/ -- dsevi...@um.es _.___
Dep. Ingeniería y Tecnología de Computadores, Facultad de Informática D|TEC
Univ.de Murcia,Campus Espinardo,30080 Murcia (SPAIN),Tel.+34868887571
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