5 ms·

All I can say is that I really miss the preprocessor. There are so many things that could easily be done with the preprocessor but instead have to be done with

• ygra 6y ago
  C# has other mechanisms to achieve what macros are commonly used for, though. In a bit, with Roslyn's source generators there will be an even better way for some of them.
  • Ididntdothis 6y ago
    It has a lot of mechanisms but they are usually way more complex with more code. For example when I do data binding in WPF I could write a five line macro that fires change notification events as needed. There are other approaches but they are way more complicated.
  • rwmj 6y ago
    One place where preprocessors shine is where the language itself has changed in an incompatible way, where "language" can be interpreted broadly including calls to external libraries. For example some function you need to call added an extra parameter: #if LIB_VERSION_GE_3 lib_f (1, NULL); #else lib_f (1); #endif It can be difficult to do this with other mechanisms where the compiler is actually compiling and therefore type checking both branches. OCaml is a pretty rich language with many features, but we fall back on preprocessors like cppo (or even cpp) to deal with these kinds of cases.
    • pjmlp 6y ago
      You can do that with .NET conditional compilation, no need for the C style macros.
      • rwmj 6y ago
        Assuming you mean this: https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/preprocessor-directives/preprocessor-if https://docs.microsoft.com/en-us/dotnet/csharp/language-refe... it looks like a restricted form of the C preprocessor. (We may quibble about whether it is separately "pre" processed or not, but even cpp doesn't run as a separate stage in modern C compilers).
        • pjmlp 6y ago
          The C pre-processor doesn't have the monopoly on conditional compilation, it wasn't even the first language to support such features, they were already available in Algol variants and Macro Assemblers.
          • rwmj 6y ago
            I'm not sure we're disagreeing. My point was that you need something separate from the language to deal with certain language compatibility issues.
            • pjmlp 6y ago
              Fair enough, but C is the snowflake here, in other languages conditional compilation is part of the language. Actually even in ISO C, the pre-processor is not required to be separated from the language, it is just kept that way in most compilers due to how C was originally implemented.
        • Ididntdothis 6y ago
          The C# preprocessor is unnecessarily restricted. It has a few features but it feels very arbitrary what they include or exclude. I think they didn’t like the idea but couldn’t avoid it totally so they did something half assed. I bet a lot of frameworks that need reflection could be replaced with macros if the preprocessor had a few more features.
          • pjmlp 6y ago
    • raverbashing 6y ago
      No, it does not "shine" It merely serves to alleviate an issue with a language limitation. And the library writers should have known better than to simply change the signature of an existing call. (also this example reminds me of all the #ifndef/#define game that headers do which should have been built into the system in the first place)
      • rwmj 6y ago
        > And the library writers should have known better than to simply change the signature of an existing call. I agree, unfortunately they do this and we have to cope with it.