> define d2r {$1*pi/180}
>
> t = d2r(15.0+0.5*i)
"define" being a (text-replacement) macro facility,
this can be understood as follows:
t = d2r(15.0+0.5*i)
= 15.0+0.5*i*pi/180
so a better definition would have been:
define d2r {($1)*pi/180}
I think similar pitfalls exist with cpp macros.
