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Please correct me if I'm wrong, but I think the word metaprogramming (MP) is used a bit too liberal in this article. When I think of MP I think of programs-writ

• oever 11y ago
  I use the term 'metaprogramming' because that's the title of the relevant chapter in Stroustrups 'The C++ programming language'. I do think that 'C++ metaprogamming' is a bit clunky, but 'C++ template programming' sounds too limited. 'compile time programming' also sounds strange. Wikipedia says: "Metaprogramming is the writing of computer programs with the ability to treat programs as their data." Writing C++ templates to treat Relax NG specifications and literal XML in C++ as input for schema validation would fit that definition.
  • igravious 11y ago
    I think 'C++ template programming' might be better also :/ The following syntax in Haskell causes a parse error in my brain: contains :: NameClass -> QName -> Bool I really want it to be contains :: (NameClass, QName) -> Bool Or even just contains :: NameClass, QName -> Bool Is it just my problem to get over or do other people have it, or is there syntactic sugar coming to my rescue?
    • gaze 11y ago
      You should get over it. It's just syntax... and it's there for a reason (Makes more sense for curried functions, and it's a holdover from logic where you say that if you have a nameclass, you have an object that sense a qname to a bool, and if you have a nameclass and a qname then you have a bool.)
      • igravious 11y ago
        What? Are you saying that I can legitimately read contains :: NameClass -> QName -> Bool two ways? Like, contains :: (NameClass, QName) -> Bool And contains :: NameClass -> (QName, Bool) ? What about four types? contains :: Urk -> NameClass -> QName -> Bool
        • Nullabillity 11y ago
          Not quite. It's equivalent to either contains :: (NameClass, QName) -> Bool or contains :: NameClass -> (QName -> Bool) In other words, you can treat it as a function taking two arguments, or one function taking one argument and returning another function.
          • theseoafs 11y ago
            It is equivalent to the second, not the first. The first is a completely distinct type -- though you can certainly write a function with that type, given the original function, by uncurrying it.
            • saurik 11y ago
              FWIW, I think the person you are responding to is using the non-Haskell requested mental syntax used by the person who asked the original question, in order so they better understand the semantics (even if at a cost of confusing them for later development in Haskell).
              • Nullabillity 11y ago
                Yup. They're distinct types, but mentally they are the same (and the standard library has functions to convert between the two forms).
        • kenko 11y ago
          No, a -> b -> c always means a -> (b -> c). a -> b -> c -> d always means a -> (b -> (c -> d)). "->" is right-associative.
    • gizmo686 11y ago
      contains :: (NameClass, QName) -> Bool is valid Haskel, and denotes that "contains" is a function that takes a tuple and returns a bool. As a matter of style, Haskellers tend to avoid writing function like this, and prefer to write functions like contains :: NameClass -> (QName -> Bool) which indicates that "contains" is a function that takes a "NameClass" and returns another function. Because this pattern is so common in Haskell, -> is defined to be right-associative, so the paranthese can be omited.
• pmelendez 11y ago
  >"DSLs that are transformed to (mostly rather repetitive) Haskell at compile time-- are MP in my idea" In it kinda the case in C++ too. C++ template system is a turing-complete machine at compiling time.