Le 16/07/2013 19:54, Claus Reinke a écrit :
// this doesn't work
function* generator(){
[1,2,3].forEach( function(x){ yield x } )
}
I have been thinking and with for..of, I can't find a good reason to use
.forEach instead of for..of.
for..of does what you need here with generators too.
This would make generators deep, violating the non-interleaving
assumptions
of intermediate callers on the call stack. This is why we accepted
generators only on condition that they be shallow. We knew at the
time that
this privileges built-in control structures over user defined ones. The
alternative would have been to omit generators completely. We agree that
shallow generators were worth it, despite this non-uniformity.
While I understand the compromise, and the wish to get in some form
of generators anyway, the discrimination against user-defined control
structures troubles me deeply. It introduces a new language construct
that defies abstraction. It means that we can no longer use functional
abstraction freely, but have to worry about interactions with generators.
For the specific case of forEach et al
What do you mean by "et al"? I don't believe .map, .reduce or .filter
are any interesting to use alongside generators.
Even if so, for..of can work too and is decently elegant (YMMV):
function* g(){
[1,2,3].map(x => {yield transform(x)})
}
becomes
function* g(){
for(x of [1,2,3]) yield transform(x);
}
David
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