[nem-en] Increment and decrement operators

[Kamil Skalski]

The rule that after } there is implicit ; or , depending on context
So your ({ x++; x } + {x++; x}) is equivalent to
( { x++;  x }, + { x++; x })

This is (not planned) side effect of making
if (x) {
  a
}
else
  b {
}
- 5

mean that we first compute  a / b and then return -5  instead of
subtracting 5 from a/b


2006/2/27, Kannan Goundan <cakoose at yahoo.com>:
>
> Why are there both "x++" and "++x" if the expression doesn't return a
> value?  Is it just to avoid syntax errors for those users who use one
> or the other out of habit?
>
> Also, I couldn't figure out exactly how the operator behaves.  It
> seems the commas in a function call are sequence points but the part
> of an infix expression aren't, which gives weird results:
>
> class Increment
> {
>    static Main() : void
>    {
>      mutable x : uint = 1;
>
>      x = 1;
>      System.Console.Write("Val: {0}", {x++; x});
>      System.Console.WriteLine(", End: {0}", x);
>
>      x = 1;
>      System.Console.Write("Val: {0}", {++x; x});
>      System.Console.WriteLine(", End: {0}", x);
>
>      x = 1;
>      System.Console.Write("Add: {0}", {x++; x} + {x++; x});
>      System.Console.WriteLine(", End: {0}", x);
>
>      x = 1;
>      System.Console.Write("Add: {0}", {++x; x} + {++x; x});
>      System.Console.WriteLine(", End: {0}", x);
>
>      x = 1;
>      System.Console.Write("Add: {0}", Add({x++; x}, {x++; x}));
>      System.Console.WriteLine(", End: {0}", x);
>
>      x = 1;
>      System.Console.Write("Add: {0}", Add({++x; x}, {++x; x}));
>      System.Console.WriteLine(", End: {0}", x);
>    }
>
>    static Add(a : uint, b : uint) : uint
>    {
>      a + b;
>    }
> }
>
> -------------------
> Output:
>
> Val: 2, End: 2
> Val: 2, End: 2
> Add: 2, End: 3
> Add: 2, End: 3
> Add: 5, End: 3
> Add: 5, End: 3
>
>
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--
Kamil Skalski
http://nazgul.omega.pl