Table – Add To Table Refactoring

The add to table function is large and hard to read so it will be refactored.  Refactoring this function will require several passes of changes.  The first round was to break the function into seven smaller functions.  The add expected data type function was already separate since it is called from three places.  The result was a simpler main function, but is still rather involved.  The separated functions are also simpler, but less than readable (and one is still quite large).

I won't detail the results since this is not the final form (and if successful, no explanation should be necessary as the code should be easy to read).

[branch table commit 23515be87b]

For the next round, I wanted to clean up the main add to table function.  There were a number of return statements that were cluttering up the function.  The first change was to restructure two of the if statements to eliminate two of the return statements.  For the others, there was a pattern with three of the separated functions returning a null pointer indicating that no further action was necessary.  The main function then checked for this null pointer and returned.

To clean this up, an empty Done structure was added with no members to be used as an exception.  Instead of these three functions returning a null, they instead throw an instance of this empty structure.  The main function catches this exception and does nothing (just returns).  This is not really an exception condition, but it cleaned up the main function quite a bit.  This mechanism allows lower-level functions to cause a return of the add to table function.

[branch table commit 69bd606994]

For the third round, there was some more attempt to make the main add to table function and some of the separated function more readable.  This involved renaming functions (again) and adding access functions to make what is being tested in if statements more self explanatory.

One of the new access functions was named has operands, which was too similar to the has operand access functions.  These were used to determine if the code has an operand (variable, constant, array, etc.) by checking if the code has an operand text function.  These functions were renamed to is code with operand.  The last operands access functions were corrected to return an integer instead of a boolean (though this didn't appear to affect its functionality).

[branch table commit 8b9b3f9a4b]