RFR 8177076: jshell tool: allow non-zero /exit

[Robert Field]

A minor update with improvements I was mulling over while I should have 
been sleeping:

     http://cr.openjdk.java.net/~rfield/8185840v1.webrev/

-Robert

On 10/31/17 22:26, Robert Field wrote:
> The seed of this is the ability to exit the jshell tool with a user 
> specified exit code.  For example:
>
>     /exit result > base ? 0 : 7
>
> However, this requires the tool launching API to support passing on 
> the exit code.
> In turn, this requires the tool to return exit codes, and do so 
> correctly for tool errors.
>
> This is the first case of a command taking a snippet as an argument.  
> Input continuation was tied to snippet input processing.
> Input, continuation, command, and snippet processing needed to be 
> unraveled.
>
> Diagnostic display, formerly only needed for snippets, needed to be 
> refactored.
>
> Tab completion needed to be handled in this new case (note integer 
> context).
>
> On testing side, StartOptionTest and its subclass ToolProviderTest 
> were a teetering pile of spaghetti that were not amenable to
> the additional demands of the new needed tests.  They have been revamped.
>
> Bugs:
>
>     8177076: jshell tool: allow non-zero /exit
>     https://bugs.openjdk.java.net/browse/JDK-8185840
>
>     8190383: JShell API: no way for the jshell tool to report exit 
> status to provider
>     https://bugs.openjdk.java.net/browse/JDK-8190383
>
> Webrev:
>
>     http://cr.openjdk.java.net/~rfield/8185840v0.webrev/
>
> Thanks,
> Robert
>