4 ms·

This is why Ada disallows empty statements. You have to explicitly write "null;" which is a lot more obvious.

• WalterBright 4y ago
  D's null statement is `{ }` which nobody is going to type by accident, whereas ';' is just a twitch of your pinky. `null` has another meaning in D, that of a null pointer. D also does not allow the syntax `a < b < c`. C does, to the eternal damnation of anyone who tries it.
  • msla 4y ago
    > D also does not allow the syntax `a < b < c`. C does, to the eternal damnation of anyone who tries it. Far be it for me to teach the Pope to pray, but would it be reasonably reasonable to make that do the right thing? If your compiler can disallow it, it can detect it, so the grammar is obviously thinkable, and the semantics might be as well.
    • lmz 4y ago
      I believe this is legal Python and does what you expect.
      • medo-bear 4y ago
        in lisp its (< a b c) The value of < is true if the numbers are in monotonically increasing order; otherwise it is false. - clhs
        • kazinator 4y ago
          The important thing is that it's unambiguous. One function is being called with three arguments. If you don't know what that function does, you look it up. No drama.
          • medo-bear 4y ago
            exactly. (< a b c) is much clearer than a < b < c
      • viraptor 4y ago
        Most of the time it does what you expect. Sometimes it has its own pitfalls unfortunately. a in b == True is one weird example...
        • steppi 4y ago
          This is tricky, but it is at least a PEP 8 violation to compare a Boolean expression to True or False with ==, and a linter will complain. Programming in Python without a linter can be perilous in general.
          • Koshkin 4y ago
            I hate when people do that (in C++).
    • afiori 4y ago
      In the syntax `a < b < c` both the `<` are different operators than the `<` in `a < b`. It is more similar to the ternary operator `a ? b : c`. It could also just be a type error: `<` takes two integers and produces a boolean, so both `(a < b) < c` and `a < (b < c)` would be invalid.
    • WalterBright 4y ago
      > would it be reasonably reasonable to make that do the right thing? I did think about that, and it's a good question. I did not out of concern for some C code translated to D then mysteriously misbehaving.
• rob74 4y ago
  This is why in Go you always have to have a block after a condition or loop statement - a single instruction is not accepted.
• jabl 4y ago
  It's a really minor point, but this is one thing I like about Rust syntax for conditionals vs. C/C++. It always requires the {} around the block, so it has no special rule for single-statement conditionals like C. At the same time, always requiring the {} means that it can get rid of the () around the condition. So all in all, it's as short or shorter than the C style syntax, and clearer without special cases.
  • medo-bear 4y ago
    this sounds so silly to people writing in s-expressions
  • rob74 4y ago
    Looks like several newer languages adopted that idea - Go does it too (also getting rid of the round brackets for loops and conditions, as well as of semicolons at the end of lines), but I'm not sure who started it...