On Monday 26 April 2010 05:11:25 pm Stefan Fuhrmann wrote: > > I saw in a later part of the patch that this is so you can make the > > function 'decode_instruction()' rely on those values. As you know, > > adding the explicit "=0", "=1", "=2" on the enum definition does not > > make any difference to the compiler, it just provides a hint to the > > human developers that these values might be significant. > > > > We need a stronger hint than this. Please add code comments in both > > the enum definition and the function 'decode_instruction()', saying > > "The enum values must match the instruction encoding values." > > Oh! I wasn't aware of that - being a C++ guy. > But as long as comments can "fix" that, so be it ... ;)
For such things, I find it useful to have some compile-time checks. Since the preprocessor cannot compare enumerated values or some other values known only at the compilation time, I use something like: #define compile_assert(x) extern int __hack__compile_assert[(x) ? 1 : -1] Then, you could add such checks (with comments explaining why this values are important) to one of the source files: compile_assert(svn_txdelta_source == 0); compile_assert(svn_txdelta_target == 1); compile_assert(svn_txdelta_new == 2); Disclaimer: I am not a Subversion developer, so I am not sure if Subversion community is willing to have such assertions in the code. Regards, Alexey.
