33  */

    34 

    35 

    36 /* NOTE: The algorithm implemented here assumes that candidate datatype lists have already been filled!

    37  *       BEFORE running this visitor, be sure to CALL the fill_candidate_datatype_c visitor!

    38  */

    39 

    40 

    41 /*

    42  *  Choose, from the list of all the possible datatypes each expression may take, the single datatype that it will in fact take.

    43  *  The resulting (chosen) datatype, will be stored in the symbol_c.datatype variable, leaving the candidate datatype list untouched!

    44  * 

    45  *  For rvalue expressions, this decision will be based on the datatype of the lvalue expression.

    46  *  For lvalue expressions, the candidate datatype list should have a single entry.

    47  * 

    48  *  For example, the very simple literal '0' in 'foo := 0', may represent a:

    49  *    BOOL, BYTE, WORD, DWORD, LWORD, USINT, SINT, UINT, INT, UDINT, DINT, ULINT, LINT (as well as the SAFE versions of these data tyes too!)

    50  * 

    51  *  In this class, the datatype of '0' will be set to the same datatype as the 'foo' variable.

    52  *  If the intersection of the candidate datatype lists of the left and right side expressions is empty, 

    53  *  then a datatype error has been found, and the datatype is either left at NULL, or set to a pointer of an invalid_type_name_c object!