Hello Jürgen, Should GNU APL report an APL error message, say "DOMAIN ERROR", rather then an assertion diagnostic for `¯1 ? 5'? The reason I ask is `3 ? ¯1' produces "DOMAIN ERROR".
Details follow: f...@centari.modelling.org[fred] $ apl -v BUILDTAG: --------- Project: GNU APL Version / SVN: 1.7 / 1022M Build Date: 2017-11-23 18:07:12 UTC Build OS: Linux 4.13.13-300.fc27.x86_64 x86_64 config.status: 'RATIONAL_NUMBERS_WANTED=yes' 'CORE_COUNT_WANTED=syl' Archive SVN: 989 f...@centari.modelling.org[fred] $ apl ¯1 ? 5 ======================================================================= ======= Assertion failed: items in Function: at in file: Simple_string.hh:286 Call stack: ---------------------------------------- -- Stack trace at Simple_string.hh:286 ---------------------------------------- 0x7F40C62DD03A __libc_start_main 0x448C25 main 0x5BB01D Workspace::immediate_execution(bool) 0x49A424 Command::process_line() 0x49ABDD Command::do_APL_expression(UCS_string&) 0x49A48F Command::finish_context() 0x4A5658 Executable::execute_body() const 0x557350 StateIndicator::run() 0x4E9494 Prefix::reduce_statements() 0x4E6BAD Prefix::reduce_END_B__() 0x557CAF StateIndicator::statement_result(Token&, bool) 0x5B6D85 Value::print(std::ostream&) const 0x50A7DD PrintBuffer::PrintBuffer(Value const&, PrintContext const&, std::ostream*) 0x45B5E8 do_Assert(char const*, char const*, char const*, int) ======================================== SI stack: Depth: 0 Exec: 0xc3a1a0 Safe exec: 0 Pmode: ◊ ¯1 ? 5 PC: 4 (5) RETURN_STATS Stat: ¯1 ? 5 err_code: 0x0 ======================================================================= ======= Regards, Fred