Re: Passing procedures as parameters to procedures.

[cis.ohio-state.edu!zaphod.mps.ohio-state.edu!howland.reston.ans.net!ira.u]

In article <1993May4.094549.13420@sei.cmu.edu>, firth@sei.cmu.edu (Robert Firth
) writes:
: [...] trying to replicate something like the Algol-60
: 
: 	real procedure Integrate ( real procedure F; real lwb, upb );
: 
: and put it in a library package somewhere.  You can't do it.

Use generics (for simple cases--99.99%):

generic
  with
    function F (X : Float)
      return Float;

function Integrate (Lower_Bound, Upper_Bound : Float)
  return Float;


function Sin (X : Float)
  return Float;

function Integrate_Sin is -- Sin many times :-)
  new Integrate (F => Sin);


I am constantly amazed that the power of generics is so widely
underestimated.  I've even heard that some people prefer to use
the C preprocessor to _simulate_ instantiations instead of using
Ada's genericity.  Please say I'm wrong.
-- 
Magnus Kempe                "No nation was ever drunk when wine was cheap."
magnus@lglsun.epfl.ch                                   -- Thomas Jefferson