Use of io!

[Josh Kamau]

Hi ;

Whats the point of using io! inside dosync if all it does is make an exception to be thrown? Please someone make me understand. 

Regards.

Josh

[Maik Schünemann]

I think It stops other code to wrap around the code with the explicit io! call.

Its declarative way of saying: I am doing io! DONT USE me inside a dosync.

--
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clo...@googlegroups.com
Note that posts from new members are moderated - please be patient with your first post.
To unsubscribe from this group, send email to
clojure+u...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
---
You received this message because you are subscribed to the Google Groups "Clojure" group.
To unsubscribe from this group and stop receiving emails from it, send an email to clojure+u...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.
 
 

[dennis zhuang]

Yep,wrap code that has side effects, prevent it to be evaluated in STM transaction.

2013/5/30 Maik Schünemann <maiksch...@gmail.com>

--
庄晓丹
Email:        killm...@gmail.com xzh...@avos.com
Site:           http://fnil.net
Twitter:      @killme2008

[Michael Klishin]

2013/5/30 Josh Kamau <joshn...@gmail.com>

Whats the point of using io! inside dosync if all it does is make an exception to be thrown?

The point is to mark side-effecting code so that you can't accidentally use it in a transaction.
--
MK

http://github.com/michaelklishin
http://twitter.com/michaelklishin

[Alex Baranosky]

Do any of you ever use io! ?  I've never used it, but could see using it if I had a transaction-heavy application.

--

[Josh Kamau]

Thanks guys. Now i understand its for "marking" functions containing io so that they blow up if they are used inside transactions.  I am still learning clojure and i have decided to take some time to understand every function in the core API.

Josh.

[Sean Corfield]

On Thu, May 30, 2013 at 1:10 AM, Alex Baranosky
<alexander...@gmail.com> wrote:
> Do any of you ever use io! ? I've never used it, but could see using it if
> I had a transaction-heavy application.
>
> On Wed, May 29, 2013 at 11:43 PM, Michael Klishin
> <michael....@gmail.com> wrote:
>> The point is to mark side-effecting code so that you can't accidentally
>> use it in a transaction.

I gather the intent is for *all* side-effecting code to be wrapped in
io! so that you can't accidentally use it with STM transactions?

The only places in Clojure and its contribs that use this are:
* await - clojure.core
* await-for - clojure.core
* transaction - java.jdbc (deprecated)
* db-transaction - java.jdbc

It sounds like all inserts and updates in java.jdbc should also be
wrapped in io! and I would expect io! to be needed in a lot of other
places in Clojure libraries across the board...?
--
Sean A Corfield -- (904) 302-SEAN
An Architect's View -- http://corfield.org/
World Singles, LLC. -- http://worldsingles.com/

"Perfection is the enemy of the good."
-- Gustave Flaubert, French realist novelist (1821-1880)

[Gary Trakhman]

What if you really want the 'bad' effects on retries?  We need io! versions and non-io! versions of side-effect functions :-)

[Gary Trakhman]

Well, more seriously, I would be against any facility that prevents me from doing something potentially useful that I might want to do.  Sprinkling potential problem spots with io! might make more sense in an application than a library.