Hi Jochen,
?= is similar with *=, +=, etc in their usage, and they are all for
convenience and readability. So if ?= does not make sense, why others does? :-P
a = a * 2
a *= 2
a = a ?: 2
a ?= 2
Cheers,
Daniel.Sun
--- 原始邮件 ---
发件人： "Jochen Theodorou [via Groovy]" <[email protected]>
已发： 2016年11月23日 上午12:47
收件人： "Daniel Sun" <[email protected]>
主题： Re: [PROPOSAL]new operator ?=
On 22.11.2016 15:25, Guillaume Laforge wrote:
> It's a feature that's often be requested.
> I think Ruby's got an equivalent with ||=, and it's often the reference
> people give when exploring our Elvis operator coming from a ruby
> background in particular.
> I've had several opportunities where I could've used this operator.
> It might make for a nice addition.
while I agree that ||= is more like what ruby offers we have the
problem, that for Groovy a||b always will be evaluated as boolean.
In fact first we apply groovy truth to a and if that is not true, we do
the same for b and if that is not true we return false, otherwise true.
Which means a = a||b would not be equal to a ||= b if that is supposed
to be the same as proposed for ?=.
What would come near to that is |, which is mapped to a method call to
"or". And then again, it has already a meaning for numbers, that does
not fit.
So for me a new operator makes more sense. But frankly...
> def foo(x) {
> return x ?: "empty"
> }
or even
> def foo(x) {
> x = x ?: "empty"
> return x
> }
vs.
> def foo(x) {
> x ?= "empty"
> return x
> }
Is that really worth it? Does it really improve readability that much?
Or maybe someone has a better example?
it is different for !in and !instanceof, because of the spacing and
because you may have them in complex expressions. But ?= is a statement
and I would very much dislike this usage as expression.
For now I am -1 on this
bye Jochen
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