[Bug-apl] Stack track on function trace

[Blake McBride]

I was tracing a function when I got:

Picd[6]  9/06/2014

Picd[8] *this:               'NO_VALUE' at Token.cc:452

----------------------------------------

-- Stack trace at Token.cc:453

----------------------------------------

0x7f64f3ac3de5 __libc_start_main

0x43e685  main

0x5595ed   Workspace::immediate_execution(bool)

0x48572a    Command::process_line()

0x47ad1d     Command::do_APL_expression(UCS_string&)

0x48fed8      Executable::execute_body() const

0x50df40       StateIndicator::run()

0x4bea95        Prefix::reduce_statements()

0x4bc223         Prefix::reduce_END_B__()

0x50e85e          StateIndicator::statement_result(Token&, bool)

0x53519e           Token::show_trace(std::ostream&, UCS_string const&, Function_Line) const

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Please let me know if you need more.

Thanks!

Blake