exception wordset

[jkotlinski]

No description provided.

[jkotlinski]

to solve:

When a THROW returns control to a CATCH, the system shall un-nest not only definitions, but also, if present, locals and input source specifications, to return the system to its proper state for continued execution past the CATCH.

[jkotlinski]

OK, so all the tests pass, which means it basically works. But need to find a good way to keep the helpful error messages.

[ekipan]

maybe put a jump vector here whose address is given as a value. The asm code could just print err but the forth code could later give it something proper, once . exists.

[jkotlinski]

I solved error messages in the most simple way I could imagine now.

Not sure if it is better than a jump vector, but it works.

[ekipan]

Or maybe insert a JSR NOP between lines 85 and 86. Later ' . could be stored there. Just as something simple.

[jkotlinski]

I messed around a little, now it prints custom error messages for some error codes.

Something still to solve: when parsing a file, and a word is not found, I want it to print the missing word.

[jkotlinski]

OK, I think it is more or less done now, except for all the things I did not think of yet.

I am not sure what implications this has for ioabort, or if there are other things that should be done differently, now that exceptions are available.

[jkotlinski]

TODO: Update manual.

[jkotlinski]

TODO: Figure out if anything ought to change related to File I/O error handling.

[Whammo]

Very cool. Thank you.
Perhaps a simple example?

[jkotlinski]

What do you think of this?

: loop begin again ;
: demo ['] loop catch . ;
demo

To break out of the endless loop, press RESTORE to raise "user interrupt" exception -28.
demo will catch and print the exception number.

[jkotlinski]

Mulled things over, and it is probably O.K. if exceptions -13 (Undefined Word) and -37 (File I/O Error) print error messages before THROW, rather than in the exception handler.

[jkotlinski]

Probably good to go.

[jkotlinski]

TODO: print unknown exception numbers.