Lots of bool operations shouldn't compile

[Thomas Kuehne]

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Don Clugston schrieb am 2006-02-28:

[snip]

> OK, there's another bug in there, comparing an int with an imaginary 
> real should also not be legal.
>
>      if (1 > -2i) { assert(0); }
>      if (1 > ireal.nan) { assert(0); }
>
> Reals and ireals cannot be compared. Ever.

Sure you can. Floats and imaginary floats can both be implicitly promoted
to complex floats.

# import std.stdio;
# 
# int main(){
#     creal a = 1;
#     creal b = 1i;
#
#     writefln("a: %s", a);
#     writefln("b: %s", b);
#    
#     writefln("1 == 1i: %s", (1 == 1i) ? true : false);
#     writefln("1 == 0i: %s", (1 == 0i) ? true : false);
#     writefln("0 == 1i: %s", (1 == 0i) ? true : false);
#     writefln("0 == 0i: %s", (0 == 0i) ? true : false);
# 
#     return 0;
# }

Thus

>      if (1 > -2i) { assert(0); }
>      if (1 > ireal.nan) { assert(0); }

are interpreted as

>      if (1 + 0i > 0 - 2i) { ... }
>      if (1 + 0i > 0 + ireal.nan) { ... }

The remaining question is: Is the second example unordered (due to the
inan) or ordered?

std.typeinfo.ti_creal._compare(creal, creal): ordered
std.conv.feq(creal, creal): unordered

http://www.digitalmars.com/d/float.html seems silent on this regard.

Thomas


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