Pre-Table – Sub-String Assignments

In researching the requirements for the new table design, specifically how to implement associated codes (which will be renamed alternate codes), there was an issue with the associated codes for sub-string assignments (LEFT$, MID$ and RIGHT$).

The sub-string assignment codes are the first associated code for the sub-string codes.  The sub-string assignment-keep codes are the first associated code of the sub-string assignment codes.  For recreation, the original sub-string code was the second associated code for each of these assignment codes.  This was necessary since the sub-string code contained the actual number of arguments as the sub-string assignment codes contain only two arguments (one for the value and one for the reference being assigned).

This circular association back to the original sub-string code was going to be a problem with the new table design and so the sub-string code associated were removed.  The first change made to the sub-string assignment table entries was to put back the original sub-string keyword name.  Since the debug name is the combination of the primary and secondary names, the secondary names were changed to remove redundancy, for example, the debug name for AssignLeft changes to LEFT$(Assign.  The affected expected test outputs were updated accordingly.

The assign string recreate function was modified to use the keyword name to look up the original sub-string code instead of using the second associated code for the sub-string assignment codes.  This caused a problem with the MID3 codes as the MID2 code was found, which contained the wrong number of arguments.  This was resolved by adding the Multiple table flag to the MID3 codes.  When this flag is set, the sub-string code found is incremented to the next code.  This change caused a problem during table initialization checking, which was modified to only check Multiple flagged entries if the Reference flag is not also set.

The assign string recreate function was also using the fact that the second associated index was set zero to detect an assignment-keep code (which are used in string list assignment statements).  The string built so far needs to be put back onto the recreation stack.  With the above changes, the assignment-keep codes no longer have associated codes.  This was resolved by adding a new Keep table flag to identify the assignment-keep codes.

[branch table commit f0c7ebdacd]