id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
3480	Easily make Typeable keys pure, so that Typeable can be handled efficiently across communications	guest		"Data.Typeable:  Easily make Typeable keys  pure(used in Eq), so that Typeable keys don´t vary from run to run. This permits an efficient storage of the keys in files and to be transmitted trough communications as well as processed without loss of efficiency. Actually gaining efficiency probably, since the keys caches are not necessary.

Currently, whenever the user needs to communicate types, he must transmit the full string name for each type. Moreover, in the reception, the programmer  is forced to handle these full string keys for mapping types to handlers, in equality checks etc. if the type keys are pure, the efficiency of key handling can be keept across communications.

short description of task:
Istead of using a Hash( stringType, generatedKey) use  hashString (string-of-type)

Long description:

1) drop the cache; drop newKey 

2) use instead  the expression:
{{{
 Key $ hashString str
}}}
whenever a new key is needed from the package `Data.HashTable`:
{{{
hashString :: String -> Int 
}}}
the key obtained is pure so: 

3) drop the ""IO"" in `typeRepKey` signature

"	task	closed	normal	7.2.1	libraries/base		fixed	Typeable, efficiency	illissius@… la@… Lennart NeilMitchell	Unknown/Multiple	Unknown/Multiple	None/Unknown	Unknown