This is another utility written in machine code, and must be loaded before a Basic program is entered. Error Handler will load below any reserved memory and at the same time protects itself by relocating the attack.
I have found this program to really come into its own when I am typing in a long listing from my favourite magazine (?). Coming to the end of my typing, I press RUN and return and close my eyes fully expecting to, but not hoping to, find an error message facing me when I open my eyes again.
Now perhaps some of you whizz kids have no problem listing a line and spotting the "bug", but I am sure there are many like me who experience considerable difficulty in identifying errors, particularly in multi-statement lines. Imagine my delight when the Error Handler pinpointed my typing error for me, saving me much trouble and hair-tearing. Yes, after the Error declaration the offending line is displayed with ??? preceding the faulty part of the line. All types of errors are handled in this way.
Fantastically, Error Handler prevents the computer from losing all variable values after encountering an error, so this feature alone is incredibly useful in debugging. What more can I say?