How to make a function table?

[mnar53]

Absolutely a newbie to D. This code mimics c, but unfortunately 
does not work:


import std.typecons;
import std.math;

alias double function(double) UNARY;


UNARY[] FCNS = [sin, cos, tan];


double[][] MAP (int idx, double[][] args) nothrow {
     UNARY f = FCNS[idx];
     foreach(i; 0 .. args.length)
         foreach(j; 0 .. args[i].length)
             args[i][j] = f (args[i][j]);
     return args;
}


what's wrong with it?