Mon, 16 Nov 2015

Forgive me Curry and Howard for I have Sinned.

Forgive me Curry and Howard for I have sinned.

For the last several weeks, I have been writing C++ code. I've been doing some experimentation in the area of real-time audio Digital Signal Processing experiments, C++ actually is better than Haskell.

Haskell is simply not a good fit here because I need:

There is however one good thing about coding C++; I am constantly reminded of all the sage advice about C++ I got from my friend Peter Miller who passed away a bit over a year ago.

Here is an example of the code I'm writing: 


  class iir2_base
  {
      public :
          // An abstract base class for 2nd order IIR filters.
          iir2_base () ;

          // Virtual destructor does nothing.
          virtual ~iir2_base () { }

          inline double process (double in)
          {
              unsigned minus2 = (minus1 + 1) & 1 ;
              double out = b0 * in + b1 * x [minus1] + b2 * x [minus2]
                              - a1 * y [minus1] - a2 * y [minus2] ;
              minus1 = minus2 ;
              x [minus1] = in ;
              y [minus1] = out ;
              return out ;
          }

      protected :
          // iir2_base internal state (all statically allocated).
          double b0, b1, b2 ;
          double a1, a2 ;
          double x [2], y [2] ;
          unsigned minus1 ;

      private :
          // Disable copy constructor etc.
          iir2_base (const iir2_base &) ;
          iir2_base & operator = (const iir2_base &) ;
  } ;

Posted at: 22:22 | Category: CodeHacking | Permalink