gap> #############################################################################
gap> ##
gap> ##
gap> ## This file tests the combination of Where and DownEnv/UpEnv, and also the
gap> ## initial backtrace (for which Where is executed in a slightly different
gap> ## execution context compared to the later Where invocations from the break
gap> ## prompt)
gap> ##
gap> ## We test with three slightly different ways to trigger an error, as they
gap> ## exhibit slight differences in how they interact with the error handling
gap> ## code.
gap> ##
gap> ## We also test what happens when UpEnv/DownEnv are asked to go beyond the
gap> ## first/last execution context.
gap> ##
gap>
gap> #############################################################################
gap> ##
gap> ## trigger error using Error()
gap> ##
gap> test:= function( n )
> if n > 2 then
> Error( "!\n" );
> fi;
> test( n+1 );
> end;;
gap> test( 1 );
Error, !
at *stdin*:24 called from
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *stdin*:28
you can 'quit;' to quit to outer loop, or
you can 'return;' to continue
brk> n; Where();
3
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:1
brk> DownEnv(); n; Where();
2
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:2
brk> DownEnv(); n; Where();
1
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:3
brk> DownEnv(); n; Where();
1
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:4
brk> UpEnv(); n; Where();
2
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:5
brk> UpEnv(); n; Where();
3
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:6
brk> UpEnv(); n; Where();
3
test( n + 1 ); at *stdin*:26 called from
test( n + 1 ); at *stdin*:26 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:7
brk> quit;
gap>
gap> #############################################################################
gap> ##
gap> ## trigger error in the kernel
gap> ##
gap> test:= function( n )
> if n > 2 then
> return 1/0;
> fi;
> test( n+1 );
> end;;
gap> test( 1 );
Error, Rational operations: <divisor> must not be zero in
1 / 0 at *stdin*:35 called from
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *stdin*:39
type 'quit;' to quit to outer loop
brk> n; Where();
3
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:1
brk> DownEnv(); n; Where();
2
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:2
brk> DownEnv(); n; Where();
1
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:3
brk> DownEnv(); n; Where();
1
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:4
brk> UpEnv(); n; Where();
2
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:5
brk> UpEnv(); n; Where();
3
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:6
brk> UpEnv(); n; Where();
3
test( n + 1 ); at *stdin*:37 called from
test( n + 1 ); at *stdin*:37 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:7
brk> quit;
gap>
gap>
gap> #############################################################################
gap> ##
gap> ## trigger method not found error
gap> ##
gap> test:= function( n )
> if n > 2 then
> return IsAbelian(1);
> fi;
> test( n+1 );
> end;;
gap> test( 1 );
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `IsCommutative' on 1 arguments at GAPROOT/lib/methsel2
.g:LINE called from
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *stdin*:51
type 'quit;' to quit to outer loop
brk> n; Where();
3
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:1
brk> DownEnv(); n; Where();
3
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:2
brk> DownEnv(); n; Where();
2
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:3
brk> DownEnv(); n; Where();
1
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:4
brk> UpEnv(); n; Where();
2
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:5
brk> UpEnv(); n; Where();
3
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:6
brk> UpEnv(); n; Where();
3
IsAbelian( 1 ) at *stdin*:47 called from
test( n + 1 ); at *stdin*:49 called from
test( n + 1 ); at *stdin*:49 called from
<function "test">( <arguments> )
called from read-eval loop at *errin*:7
brk> quit;
gap> QUIT;
