Translator – Internal Functions (Release)

During testing of the “wrong number of arguments” error, it was noticed that the error was reported on the closing parentheses. While this is acceptable, it would be better if the error pointed to the actual function. However, the caller always pointed to the token that caused the error. Therefore, in order to report an error at any token, the token pointer argument of the add_token() function was changed to a reference, so that it could be changed to any token so that caller will point to this token instead when the error is reported.

The name2 member is being used for the name to output during testing, so for example, for Mid2_Code and Mid3_Code, name2 is set to “MID2$(” and “MID3$(” so that is can easily be seen which code is in the token. This was needed when outputting internal function tokens in addition to operator tokens. So instead of copying these lines of code, a new access function debug_name() was added to get the appropriate name for debug test output.

I also realized there were some memory leaks in the code - the EOL token was not deleted; when an error occurs, the token of the error was not deleted; and when the token is replaced (see above), the original token was not deleted. Therefore, the code was cleaned up to prevent these memory leaks.  Nothing was done when the “BUGs” occur since these should not happen once the code is debugged.

To make the code clearer, “Error_” was added to all the error and “BUG_” was added to all the diagnostic error Translator status enumeration names. By the way, each of theses codes is only used in one place so that it is easy to figure where an error occurs (if one “stack empty” was used instead of five unique codes, then if one occurs, there would be confusion which place in the code it came from).

The code now checks the number of arguments for internal functions and ibcp_0.1.7-src.zip has been uploaded at Sourceforge IBCP Project along with the binary for the program. Next handling assignment statements and the concept of references...

Translator – Internal Functions (Implementation)

The number of arguments member needs to be added to the TableEntry structure and values to the table entries along with an access function to this member in the Table class. New entries are needed for the MID$, ASC and INSTR functions with the appropriate number of arguments. A new multiple entry flag is needed to the first entry for each of these functions to indicate that more entries exist with different number of arguments.

The check for the number of arguments for internal functions will be added to the closing parentheses token processing in the array or function section. If the token popped off of the hold stack is an internal function and the number of operands doesn't match the number of arguments in the table, then if the multiple entry flag is set it needs to search for another entry of the function that matches the number of operands. If found, the the token's index will be changed to the new entry's index. Otherwise a “wrong number of arguments” error will occur.

A new table search function is needed that will search for a function with a specific number of arguments. The index of the first entry for the function will be specified assuming that it has already been checked for the number of arguments (this is the index the Parser originally returned). The search will proceed with the entry after the index and continue until the end of the internal functions (when an entry with a NULL name if found). The additional entries must be in the same internal functions section (words with parentheses).