Hi,
The signature from the Clean Book is correct, + is not only a binary
function but also a type class taking one type argument (as defined on
page 16):
class (+) infixl 6 a :: a a -> a
The confusion might originate from the fact that this definition is
shorthand notation for:
class + a where
(+) infixl 6 :: a a -> a
This definition clarifies the fact that + is a binary function taking two
arguments and a type class as well taking a single type argument.
The shorthand notation is probably introduced for type classes that only
define a single function with the same name as the type class.
Regards,
Thomas
[EMAIL PROTECTED] wrote:
This seems like an obvious statement, but I am reading the Clean Book
and saw this annotation for double:
double :: a -> a | + a
which reads as "double is a function which takes an argument of type a
and returns and value of type a provided that a version of + is defined
which can handle arguments of type a"
But my question is: since (+) is a binary function, shouldnt that read:
double :: a -> a | + a a
--
Terrence Brannon - SID W049945
1111 Polaris Pkwy, OH1-1141, Columbus, OH 43240
818-359-0893 (cell)
614-213-3426 (fax)
------------------------------------------------------------------------
This communication is for informational purposes only. It is not
intended as an offer or solicitation for the purchase or sale of any
financial instrument or as an official confirmation of any transaction.
All market prices, data and other information are not warranted as to
completeness or accuracy and are subject to change without notice. Any
comments or statements made herein do not necessarily reflect those of
JPMorgan Chase & Co., its subsidiaries and affiliates. This transmission
may contain information that is privileged, confidential, legally
privileged, and/or exempt from disclosure under applicable law. If you
are not the intended recipient, you are hereby notified that any
disclosure, copying, distribution, or use of the information contained
herein (including any reliance thereon) is STRICTLY PROHIBITED. Although
this transmission and any attachments are believed to be free of any
virus or other defect that might affect any computer system into which
it is received and opened, it is the responsibility of the recipient to
ensure that it is virus free and no responsibility is accepted by
JPMorgan Chase & Co., its subsidiaries and affiliates, as applicable,
for any loss or damage arising in any way from its use. If you received
this transmission in error, please immediately contact the sender and
destroy the material in its entirety, whether in electronic or hard copy
format. Thank you. Please refer to
http://www.jpmorgan.com/pages/disclosures for disclosures relating to UK
legal entities.
------------------------------------------------------------------------
_______________________________________________
clean-list mailing list
[email protected]
http://mailman.science.ru.nl/mailman/listinfo/clean-list
_______________________________________________
clean-list mailing list
[email protected]
http://mailman.science.ru.nl/mailman/listinfo/clean-list
