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gus_massa • today at 2:16 AM • 1 reply • view on HN

Thanks. I missed it.

I really dislike that, because it hides the control flow too much. Perhaps I'm biased by Racket, where it's easy to define something weird using macros, but you should not do unexpected weird things.

For example you can define vector-set/drop that writes a value to a position of a vector, but ignores the operation when the position is outside the vector. For example

  (vector-set/drop v -2 (print "banana"))
With a macro is possible to skip (print "banana") because -2 is clearly out of range, but if you do that everyone will hate you.

Replies

ygra • today at 6:41 AM

I think in the context of C# this is not exactly unexpected since there are various operators that apply conditional execution (and evaluation) to parts of an expression. All of them start with ?, though (? :, ??, ?., ?[], ??=), so except for casts to nullable types, every question mark in an expression signals that control flow is about to happen and it's been that way in C# for quite a while.