6 ms·

And then what would I need to type to write a log message?

• ufo 11y ago
  You pass a lambda that returns the debug message. With javascripty syntax: debug( function(){ return "my expensive log message" }) BTW, if your language is lazily evaluated (like Haskell) then you don't need to do this because arguments will only ve evaluated when they are needed.
  • MichaelGG 11y ago
    The downside there is you can still end up allocating a closure. Whereas an expanded macro shouldn't cost anything. (A sufficiently smart compiler might be able to optimize the closure allocation.)
    • FeepingCreature 11y ago
      A sufficiently modern language (like, saaaaay, D2) could also give you a type like "closure you don't intend to escape" (let's call this a "scoped closure", or if you will, "scope string delegate()"), and eschew allocation entirely without requiring optimization.