Re: Request for feedback | Implementation strategy for error linkage

[Helmut Eller <eller dot helmut at gmail dot com>]

* Charles Turner [2011-04-15 16:51] writes:

>> Most of those exceptions carry stacktraces; the stacktrace is filled in
>> at the point where the exception is created.  From the stacktrace you
>> can extract: the JVM-level class name, JVM-level method name, source
>> filename and source line number.  That should be enough to highlight the
>> source line.  
>
> IIUC, that would allow one to highlight where in the Kawa source code
> the error was raised, not where in the input the error occurred. This
> wouldn't allow me to highlight the representative portion of the input
> forms.

Right, the frame for the input form is not necessarily on top of the
stacktrace; it can also be farther below.  It will be on the stack
unless the frame was removed by tail-call optimization (which is not
enabled by default).

E.g. you have a stacktrace like:

        at gnu.mapping.MethodProc.matchFailAsException(MethodProc.java:105)
        at gnu.mapping.Procedure.check1(Procedure.java:333)
        at atInteractiveLevel$1.run(stdin:1)
        at gnu.expr.ModuleExp.evalModule2(ModuleExp.java:286)
        at gnu.expr.ModuleExp.evalModule(ModuleExp.java:187)
        at kawa.Shell.run(Shell.java:281)
        at kawa.Shell.run(Shell.java:194)
        at kawa.Shell.run(Shell.java:175)
        at kawa.repl.main(repl.java:852)

you could scan the stack until you find a frame for the REPL input port,
stdin:1 in the example.  Alternatively you could make every frame
clickable in some way.  E.g. clicking on the first frame could display a
popup window showing part of the file MethodProc.java around line 105
while clicking on the stdin:1 frame would jump directly to the input
position.

Helmut