Implicit 'this' return for void methods

[Peter Levart]

On 04/01/2014 11:28 AM, Bruce Chapman wrote:
> Slightly preceding Ulf's coin proposal by a few hours was
>
> http://mail.openjdk.java.net/pipermail/coin-dev/2009-March/001134.html
>
> Where I suggested the "naked dot" notation (coined in 
> http://mail.openjdk.java.net/pipermail/coin-dev/2009-March/000855.html) has 
> better value as ".. a
> syntax for referring to the receiver of a method inside arguments to the
> method."
>
> More formally, the naked dot  (at the start of an expression, not 
> following an invocation to a void method) would refer to the receiver 
> of the innermost surrounding invocation expression.

A: What is the receiver of the invocation of a static method?

B: What is the receiver of the invocation of a constructor?


Regards, Peter


>
> and so to answer Guy's question below in terms of my original 
> intention rather than Ulf's proposal, .indexof("Q") would use 
> myVeryLongNamedString as its receiver.
>
> I see particular value for these naked dot expressions in creating 
> fluent APIs such as builder patterns. As suggested in my coin post, 
> there is also value for passing enums or named constants to methods 
> when (as is often the case) these named constants are defined in the 
> same class as the method being invoked. In a highly informal sense, 
> the naked dot enables on demand changing of the scope to be that of 
> the invocation expression's receiver,
>
> I think with this interpretation of the meaning of naked or leading 
> dot, Guy's compromise restriction below is not required.
>
> Bruce
>
>
> On 27/03/2014 4:51 a.m., Guy Steele wrote:
>>
>> I am a bit more skeptical about expressions that begin with a dot 
>> because of potential
>> confusion about which expression is referred to:
>>
>>      myVeryLongNamedString.subString(.indexOf("C”), .indexOf("Q”))
>>
>> seems clear enough, but what about:
>>
>>      myVeryLongNamedString.subString(.indexOf("C”) + 
>> otherString.length(), .indexOf("Q”))
>>
>> Does the second occurrence of .indexOf use myVeryLongNamedString or 
>> otherString?
>>
>> A compromise would be to allow leading-dot expressions to occur only 
>> within the arguments
>> of the method call whose target is the object which the leading-dot 
>> expressions are expected
>> to use as their target, and if there are such leading-dot expressions 
>> within the arguments
>> then the arguments must not contain any non-leading-dot field 
>> references or method calls.
>> Just a thought for discussion.  This would be considered a separate 
>> mechanism from the
>> chaining-of-void-methods mechanism (it was a very clever idea to try 
>> to unify them in Ulf's
>> original proposal, though).
>>
>> —Guy
>>
>>
>
>
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