Am Freitag, den 15.08.2014, 23:10 +0300 schrieb Wolfgang Jeltsch:
Hi,
the module Control.Arrow declares a set of rules for the Arrow class. It
is marked “Trustworthy”, probably to allow these rules to actually fire.
Now these rules are only correct for class instances that actually
That's an interesting question. I'm not even close to an expert, but I
*think* that parametricity prevents those particular rules from breaking
Safe Haskell guarantees. The laws may not *hold* for a broken instance, but
I don't *think* that lets you break type safety or IO encapsulation.
On Nov
Hi,
the module Control.Arrow declares a set of rules for the Arrow class. It
is marked “Trustworthy”, probably to allow these rules to actually fire.
Now these rules are only correct for class instances that actually
satisfy the arrow laws. If the author of another module defines an
instance of
