Translator – Operand Processing Debugging

The Ninth (LET command) test contained multiple equal assignments, so the expected results needed to be updated since the multiple equal assignments feature was removed. Once the expected results were corrected, including removing the comma sub-code that was only needed to tell the difference between multiple equal and comma assignments, this test was successful. There was no necessity to used debugging here, but on to the Tenth (PRINT command) test that is crashing...

The Tenth test was crashing because of an invalid status code was being returned. This was tracked down to the add print code routine that was calling the process final_operand routine incorrectly (passed status variable as an argument instead of setting it to the return value).

Now all the PRINT commands were generating a “done stack not empty” bug error. This was caused by the hidden print codes (PrintDbl, PrintInt and PrintStr) not being popped from the done stack. These should not have been pushed on to the done stack and this was caused because these codes did not have the Print flag set in the table, which would have prevented them from being pushed on to the done stack.

Next the PRINT commands were generating a “invalid use of print function” error at the PRINT command. This was caused during the processing of the last hidden print code on the statement when the top of the command stack was checked for the PRINT command (the stack was empty, so the check was not performed). The PRINT command had been popped by the End-of-line command handler that called the PRINT command handler, which handles the last print code by calling the add print code routine. The add print code calls the process final operand routine, which checked for the print command. The solution was for the End-of-line command handle to leave the command on top of the stack when the command's handler is called and then pop the command off upon returning.