fcn integrate(F,f,a,b,steps){
   h:=(b - a) / steps;
   h*(0).reduce(steps,'wrap(s,i){ F(f, h*i + a, h) + s },0.0);
}

fcn rectangularLeft(f,x)    { f(x) }
fcn rectangularMiddle(f,x,h){ f(x+h/2) }
fcn rectangularRight(f,x,h) { f(x+h) }
fcn trapezium(f,x,h)        { (f(x) + f(x+h))/2 }
fcn simpson(f,x,h)	    { (f(x) + 4.0*f(x+h/2) + f(x+h))/6 }

args:=T( T(fcn(x){ x.pow(3) }, 0.0, 1.0,   10),
         T(fcn(x){ 1.0 / x },  1.0, 100.0, 1000),
         T(fcn(x){ x },        0.0, 5000.0, 0d5_000_000),
         T(fcn(x){ x },        0.0, 6000.0, 0d6_000_000) );
fs:=T(rectangularLeft,rectangularMiddle,rectangularRight,
      trapezium,simpson);
names:=fs.pump(List,"name",'+(":"),"%-18s".fmt);

foreach a in (args){
   names.zipWith('wrap(nm,f){
      "%s %f".fmt(nm,integrate(f,a.xplode())).println() }, fs);
   println();
}