5 ms·

if(foo) I avoid doing this because it looks like a function call.

• kybernetikos 13y ago
  In an appropriately powerful language, it could be a function call.
  • a1369209993 13y ago
    after #define if(X) LET(_it,X) if (_it) it would be a macro call
    • yoklov 13y ago
      I'm fairly certain that shadowing a keyword with a macro is forbidden by the standard (or invokes UB?) but this will still work for most compilers, provided LET is defined reasonably. Hm, something like #define LET(name, X) \ for (int let_once_=1, name=(X); \ let_once_; \ let_once_=0) may be reasonable, though tokenpasting in __LINE__ for good measure might be necessary for nesting.
      • 30thElement 13y ago
        Shadowing keywords is perfectly valid, although I believe you can't shadow keywords in standard headers so that compiler writers don't need to worry about it. It gives rise to some "useful" C/C++ features that should never be used, like if you want to access private members in foo.cpp, do #define private public #include "foo.cpp" #undef private
        • TazeTSchnitzel 13y ago
          I can imagine some insidious menace adding this to the top of a file: #define public protected
          • yoklov 13y ago
            I once someone jokingly do (the second only always works in C, not C++) #define else #define struct union Evil!
  • TheBoff 13y ago
    This is all very well if you have a friendly, high level scripting language like Ruby, but I'm definitely glad I don't have to write a C compiler where functions can take arbitrary blocks of code.
    • swift 13y ago
      Apple took care of it for you: http://en.wikipedia.org/wiki/Blocks_(C_language_extension) http://en.wikipedia.org/wiki/Blocks_(C_language_extension)
    • rat87 13y ago
      > In an appropriately powerful language, it could be a function call. > This is all very well if you have a friendly, high level scripting language like Ruby, but I'm definitely glad I don't have to write a C compiler where functions can take arbitrary blocks of code. That's a surprisingly good setup because in Smalltalk(one of ruby's main ancestor languages) if/else is a method which takes a block closure. a ifTrue: [ l log: 'a is true'] ifFalse: [ 'a is false'] while in ruby if else is a syntatic construct if a l.log ('a is true') else l.log ('a is false') end probably more for perceived clarity/comfortability then speeds sake.
  • breadbox 13y ago
    Which is exactly why you don't do it in a language where it isn't.
    • kybernetikos 13y ago
      Why should a developer have to have headspace for a special class of construct? And what difference does it make in practice whether it is a keyword or a function - why do you think it's so important that they are obviously different in the code - does their being part of a special category have any practical implications?
• deleted 13y ago
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