BASIC symbolic debugger

The BASIC symbolic debugger facilitates the debugging of new BASIC programs and the maintenance of existing BASIC programs. The BASIC debugger requires sys2 privileges and has these general capabilities:

  • Step through execution of programs in single or multiple steps.
  • Transfer to a specified line number.
  • Break execution at specified line numbers or when specified logical conditions have been satisfied.
  • Display and/or change any variables, including dimensioned variables.
  • Trace variables.
  • Enter the system debugger.
  • Direct output to either the terminal or the printer.
  • Display and/or pop the gosub stack.
  • Display source code lines.

The BASIC debugger can be entered at execution time when:

  • BREAK key is pressed.
  • d (debug) option is specified with the TCL run command.
  • debug statement is executed in the program.
  • Runtime error is encountered (unless the a (abort) option of the TCL run command is selected).
  • abort statement is executed in the program.

When the BASIC debugger is entered, it indicates the source code line number to be executed next and prompts for commands with an * asterisk.