Implicit 'this' return for void methods

[Bruce Chapman]

On 3/04/2014 6:01 p.m., Peter Levart wrote:
> 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?

Peter,

I haven't checked the JLS formal terminology but in both cases it is the 
class's static context, such that a naked dot could only precede static 
methods and fields.

Bruce

>
>
> 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
>>>
>>>
>>
>>
>> ---
>> This email is free from viruses and malware because avast! Antivirus 
>> protection is active.
>> http://www.avast.com
>>
>>
>
>


---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com