Translator – Assignments (Change)

The way assignment and list assignment statements are processed needs to be changed to work with the expression type handling. Currently the assignment tokens are processed as operators, pushed to the hold stack when received and processed when emptied be a lower or same precedence token is received (an EOL token). The processing is performed by the find code routine activate by seeing the reference table flag set, with the additional list assignment processing in the add operator routine after find code returns.

A better method is to process assignments and list assignments as the statement is processed. This means as each comma and equal tokens are received, the data types of items being assigned are checked immediately. The first item received (a token with no parentheses, a token with parentheses or a sub-string function) determines the type of the assignment. For each additional item received in the assignment list, the data type of the item must match exactly, except for the string data type where strings and sub-strings may be mixed in the same list assignment statement.

Once the expression starts, the expression type is set to either Numeric (for the double and integer data type since both can accept either for an assignment value) or String. At the end of the statement, the data type of the expression will be checked, a hidden conversion operator will be added if necessary, followed by the assign or assign list token.

This new method is simpler than the current method, which contained involved code for detecting errors in the list assignment – the first error in the statement needed to be reported. Complicating matters was the fact that the assignment list items are processed backwards because the items are popped from the done stack in the reverse order from how they were received.