Local Variable Type Inference - prototype

[Robert Field]

On 03/10/16 14:21, Remi Forax wrote:
> At least, jshell need some tweaks :)

Yes, it will.  Thanks Remi!

It will need the analysis pass of the compiler run so that the type can 
be determined.  Variables are implemented as fields.

Is this something I should work on now?

-Robert

>
> $ /usr/jdk/jdk-9/bin/java -Xbootclasspath/p:langtools/dist/lib/jdk.compiler.jar:langtools/dist/lib/jdk.jshell.jar:langtools/dist/lib/jdk.internal.le.jar:langtools/dist/lib/jdk.jdi.jar jdk.internal.jshell.tool.JShellTool
> |  Welcome to JShell -- Version 9-internal
> |  Type /help for help
>
> -> void m() {
>>> var a = 3;
>>> }
> |  Added method m()
>
> -> m()
>
> -> var a = 3;
> Exception in thread "main" java.lang.StringIndexOutOfBoundsException: begin -1, end -1, length 10
> 	at java.lang.String.checkBoundsBeginEnd(String.java:3122)
> 	at java.lang.String.substring(String.java:1910)
> 	at jdk.jshell.Wrap$Range.part(Wrap.java:168)
> 	at jdk.jshell.Wrap$RangeWrap.<init>(Wrap.java:350)
> 	at jdk.jshell.Wrap.varWrap(Wrap.java:97)
> 	at jdk.jshell.Eval.processVariables(Eval.java:227)
> 	at jdk.jshell.Eval.eval(Eval.java:116)
> 	at jdk.jshell.JShell.eval(JShell.java:355)
> 	at jdk.internal.jshell.tool.JShellTool.processCompleteSource(JShellTool.java:1923)
> 	at jdk.internal.jshell.tool.JShellTool.processSource(JShellTool.java:1911)
> 	at jdk.internal.jshell.tool.JShellTool.processSourceCatchingReset(JShellTool.java:652)
> 	at jdk.internal.jshell.tool.JShellTool.run(JShellTool.java:632)
> 	at jdk.internal.jshell.tool.JShellTool.start(JShellTool.java:427)
> 	at jdk.internal.jshell.tool.JShellTool.start(JShellTool.java:400)
> 	at jdk.internal.jshell.tool.JShellTool.main(JShellTool.java:390)
>
> Rémi
>
> ----- Mail original -----
>> De: "Maurizio Cimadamore" <maurizio.cimadamore at oracle.com>
>> À: platform-jep-discuss at openjdk.java.net
>> Envoyé: Jeudi 10 Mars 2016 15:48:25
>> Objet: Local Variable Type Inference - prototype
>>
>> Hi,
>> I've pushed the first iteration of the local variable type inference
>> prototype in the sandbox repository[1]. For those willing and brave
>> enough to experiment, the branch name is "JEP-286-branch". We are also
>> working to get some ready-made binary snapshots out of the door and hope
>> to have an update on that soon.
>>
>> This first iteration supports the 'var-only' syntax style:
>>
>> var s = "Hello!";
>>
>> That is, the type of 's' is inferred from the initializer, and no
>> special assumption is made about mutability.
>>
>> Please share your experience with the prototype. For comments on this
>> feature please refer to the survey[2] that Brian posted few days ago.
>>
>> Maurizio
>>
>> [1] - http://cr.openjdk.java.net/~chegar/docs/sandbox.html
>> [2] -
>> http://mail.openjdk.java.net/pipermail/platform-jep-discuss/2016-March/000037.html
>>