Translator – Data Types (Implementation)

The final implementation of the data type handling was completed except for assignment operators – these will take a little extra processing because of the references (which are not convertible), plus the assignment list operator does not have a fixed number of operands. The assignment operators will be handled later.

The new find_code() function returns a Status enumeration value, either Good upon success or one of the three new error codes for the “excepted <data type>” errors. A reference to the token is passed so that it can be changed to point to the error. I realized that the comma and close parentheses tokens were not being deleted in all cases. There needs to be some sort of memory leak checking added to the program. The new and delete operators can probably be overloaded, so some checking can be added. This is a side-project for another day, but it is needed.

Testing began with the existing Translator test inputs (1 through 5) – some differences were expected (new conversion codes). What follows are some of the changes that were needed as the debugging progressed:

When the operands are being popped off of the done stack (the operand array needs to be filled in reverse order), the reference flags needed to be cleared (no need to check if it is set first), just like was previously being done for operators and internal functions.

When checking the associated codes and a convertible match is found, it is only recorded if no convertible match has been found so far (in other words, find only the first convertible match).

When changing the token to a new associated code, in addition to changing the index in the token, the data type also needed to be set to new code's data type, which might be different than the main code (for example Abs returns Double, but AbsInt returns Integer).

Quite a few of the expressions in the existing test inputs are not working correctly, or worse, causing the program to crash. One test input VAL(STR$("1.23")) was written incorrectly in the first place, which should have been VAL(STR$(1.23)) or STR$(VAL("1.23")), but at least the code properly detected this error.  Debugging continues...