PROPOSAL: Language Escape Operator

Joseph D. Darcy Joe.Darcy at Sun.COM
Thu May 14 22:41:10 PDT 2009

Hello Bruce.

More proposal catchup...

brucechapman at wrote:
> Title Language Escape Operator
> latest html version at
> AUTHOR(S): Bruce Chapman
> There is great potential for syntactic sugars to be implemented in tools rather
> than the Java language. One requirement of such a mechanism is that the sugared
> form is NOT valid java source code (otherwise the meaning is ambiguous - is a
> piece of code intended as is, or intended to be desugared). In order to future
> proof such mechanisms it is also desirable that such a syntactic sugar form will
> never become a valid java form due to some unanticipated future language change.
> A simple way to ensure this is to reserve a character as a language escape,
> effectively it indicates that source code is at that point escaping from the
> java language.

Hmm, not sure how I feel about reserving a character to provide for 
language escape mechanisms; it is certainly easy to implement today 
though ;-)

In the beginning, Java did reserve certain keywords to prevent their 
(mis)use ("auto", "goto") and at least "auto" has appeared in a coin 
proposal or two.  There is certainly potential for code transformers to 
provide useful services, but in the absence of widely-used facilities 
around these lines, I'm inclined to keep the characters available for 
future changes within Java itself.


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