Combinatorial Specification

The language Abel is widely used.
     // Input Defintions
	    sel = PIN 2;
	    cut = PIN 3;
	    a3 = PIN 3;      a4 = PIN 4;
	    a5 = PIN 5;      a6 = PIN 6 
	    a7 = PIN 7;

     // Ouput definitions
	    run = PIN 19;       
	    stop = PIN 18;  
	    hold = PIN 17;

     // Equations

	    abus = [ a7, a6, a5, a4, a3 ];

	    top = sel & ~cut;

	    run = sel & (abus == 5);

	    stop = top & ~run;

	    hold = top & run;
     // EOF
This example is an entirely combinatorial PAL.