If you do something stupid like
: TT THEN ;
(in real life it's always part of a much more complex function)
then in VFX out of the box, you get:
CS=0033 FS=0000 GS=0000
RAX=0000:0000:0047:5A10 RBX=0000:0000:0000:0000
RCX=0000:0000:0000:0000 RDX=0000:0000:0047:46B8
RSI=0000:7FFF:77F0:5D90 RDI=0000:0000:1FD0:E000
RBP=0000:7FFF:77F0:4D58 RSP=0000:7FFF:77EF:4D08
R8 =0000:7FFF:77F0:5D90 R9 =0000:0000:1FD0:E000
R10=0000:0000:0000:0000 R11=0000:0000:0000:0246
R12=0000:7FFF:77EF:4C78 R13=0000:7FFF:77F0:5D50
R8 =0000:7FFF:77F0:4D58 R9 =0000:7FFF:77EF:4D08
RIP=0000:0000:0048:20A5 EFLAGS=0001:0246
--- RS top ---
$0000:0000:0048:2C3F >C_RES_BRANCH
$0000:0000:0042:FBDB DEFER
$0000:0000:0042:1C41 THEN
$0000:0000:0042:B1A3 (NDCS,)
$0000:0000:0047:8464 NDCS-REF
$0000:0000:0042:FBDB DEFER
$0000:0000:0042:F622 (INTERPRET)
$0000:0000:0042:FBDB DEFER
Signal number SIGSEGV
at address 0000:0000:0048:20A5, probably in >ARES
and you have to go right to the bottom to get a clue.
If you use Nick's critical error handler, you get instead:
Illegal memory access, probably in >ARES, called from:
>C_RES_BRANCH DEFER THEN (NDCS,) NDCS-REF DEFER (INTERPRET) DEFER
which at least gets you to the clue in the first line, and even more of a clue in the second line.
But inexperienced Forthers are initially unaware of how to interpret the trace.
It would be really good if VFX told you straight
"Suspected mismatched THEN in definition TT"
