This has almost nothing to do with case statements or switches. Switch cases
are expressions, expressions have a defined evaluation process. That process
includes short circuiting boolean logic. Channel sends on the other hand have
no such short circuiting, whether used in a select case or not. There is no
more eagerness in a select case than anywhere else. Consider:
foo := true || fn()
someBoolChan <- true || fn()
select {
case someBoolChan <- true || fn():
}
In none of those three cases is fn called. In neither of the channel sends is
the evaluation of the expression on the right dependent on whether the channel
is nil or not.
//jb
On 31 Dec 2017, at 12:47, dc0d
<kaveh.shahbaz...@gmail.com<mailto:kaveh.shahbaz...@gmail.com>> wrote:
Indeed everything works according to the specs. That is what is being
questioned (the specs).
This behavior for case clause of select statements have different semantics
than case clause of switch statement.
While the latter gets evaluated lazily (short circuited), the former gets
evaluated eagerly - inconsistent semantics for looking-the-same syntax.
Here all the values will get prepared first, whether or not they are going to
be used. And only after this step, the select statement would check if a
channel is nil or not.
While it should be other way around. First the select statement should check if
a participant channel is nil. And only when a channel is not nil, the payload
should get evaluated.
This semantic works in reverse.
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to
golang-nuts+unsubscr...@googlegroups.com<mailto:golang-nuts+unsubscr...@googlegroups.com>.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
