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Perfect Hash Function Generator

6. Things Still Left to Do

It should be "relatively" easy to replace the current perfect hash function algorithm with a more exhaustive approach; the perfect hash module is essential independent from other program modules. Additional worthwhile improvements include:

• Make the algorithm more robust. At present, the program halts with an error diagnostic if it can't find a direct solution and the `-D' option is not enabled. A more comprehensive, albeit computationally expensive, approach would employ backtracking or enable alternative options and retry. It's not clear how helpful this would be, in general, since most search sets are rather small in practice.

• Another useful extension involves modifying the program to generate "minimal" perfect hash functions (under certain circumstances, the current version can be rather extravagant in the generated table size). Again, this is mostly of theoretical interest, since a sparse table often produces faster lookups, and use of the `-S' switch option can minimize the data size, at the expense of slightly longer lookups (note that the gcc compiler generally produces good code for switch statements, reducing the need for more complex schemes).

• In addition to improving the algorithm, it would also be useful to generate a C++ class or Ada package as the code output, in addition to the current C routines.