TI99E Common Errors and Best Practices

TI99E Common Errors

There is basic error checking on most of the functions to avoid illegal values being introduced, but there are no error or warning message indicators. In most situations, illegal values will make the program crash with a runtime error, in many others, it will simply cause the function to exit without any visual indication. In case of any persistent logic errors or unexpected results, always try to isolate these errors by displaying critical parameters on the screen prior to sending them to the TI99E functions. Do not alter the code in the TI99E functions. The functions have gone through a lot of unit and regression testing and should be stable, even if they are not 100% guaranteed to be bug free. When in doubt, make sure to make a copy of the original function, comment out the original, then test any changes using the function copy. Below you will find a list of common mistakes you may encounter as you become familiarized with TI99E:
- Missing parameters in functions (all parameters are mandatory)
- Missing or extra parentheses
- Order of parameters (x,y instead of y,x)
- Not using TI_SYNC() to refresh graphics screen.
- Declaring or modifying reserved variables.
- Leaving a space between call and the subprogram name and not ending functions with parentheses (example: typing CALL CLEAR instead of CALL_CLEAR()).
- Not using quotes ("") for string values in DATA statements.
- Misspelled variables. DBPro does not check for undefined variables. For example: Spaceship_x = 100 : Spaceship_y = 100 : call_locate(1, Spaceshp_y, Spaceship_x) will result in a runtime error but not a compiler error (Spaceshp_y is a typo, value = 0).

TI99E Best Practices

- Prefix your own variable names to avoid altering reserved variables. For example, abc_sprite, xyz_color, etc.
- Prefix your own function names. This will make it much easier to organize your functions and separate them from the TI99E functions.
- Avoid modifying TI99E functions. Instead, copy an existing function and rename it for your own use.

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Copyright © Carlos Santiago Lebron - TI99 Environment 2020