This one is hard to explain, so I was about to attach a workspace that reproduces the error.
However... As I tried to do a )SAVE to save the workspace, the interpreter crashed and of course I was editing functions directly in the workspace so they weren't saved. I'll rewrite it so I can show you. For now, take a look at the crash report: Assertion failed: sub_idx < values.size() in Function: save in file: Archive.cc:743 Call stack: ---------------------------------------- -- Stack trace at Archive.cc:743 ---------------------------------------- 0x7f95e7e21de5 __libc_start_main 0x434165 main 0x51c42d Workspace::immediate_execution(bool) 0x46123d Command::process_line() 0x460e9f Command::process_line(UCS_string&) 0x51f33e Workspace::save_WS(std::ostream&, std::vector<UCS_string, std::allocator<UCS_string> >&) 0x44056c XML_Saving_Archive::save() 0x4429cf do_Assert(char const*, char const*, char const*, int) ======================================== SI stack: Depth: 1 Exec: 0x7f95c40030d8 Pmode: ∇ disploop[5] PC: 22 ← Stat: disp ← '.#'[1+S] err_code: 0x50005 thrown: at Value.cc:1033 e_msg_1: 'INDEX ERROR' e_msg_2: 'disploop[5] disp←'.#'[1+S]' e_msg_3: ' ^ ^' Depth: 0 Exec: 0x18a9cb0 Pmode: ◊ 10 disploop DD PC: 3 ENDL Stat: 10 disploop DD err_code: 0x0 thrown: at StateIndicator.cc:39 e_msg_1: 'No Error' e_msg_2: '' e_msg_3: '' ============================================================================== *** immediate_execution() caught other exception *** Regards, Elias