Sindbad~EG File Manager

/*  These are the possible values of 'mainchoice'                     */

#define ORDINARY  0       /*  y=f(x) */
#define COMPARE_SAME 1    /* two graphs on the same axes */
#define COMPARE_DIFFERENT 2 /* two graphs on different axes */
#define MC_INEQ 3         /*  y < f(x) or f(x) < y < g(x) */
#define MC_SET 4          /*  arbitrary relation with shaded interior */
#define PARAMETRIC 5
#define POLAR_CIRCULAR 6  /* axes drawn as circles and radial lines */
#define POLAR 7           /* user specifies xmax and ymax */
#define POLYROOT 8        /* graph complex roots of a polynomial */
#define ODE 9             /* graph y' = f(x,y)                   */
                          /* we draw in both directions, and direction
                             fields work.  */
#define ODE2 10           /* Two odes  y' = f(x,y) and x'= g(x,y)  */
                          /* Drawing is over a parameter interval, one
                             direction only, but direction fields work. */
#define ODESYSTEM 11       /* graphically solve an ode x'=f(t,x,y), y'= g(t,x,y) */
                          /* if t does not occur, mainchoice should be ODE2 instead */
                          /*  direction fields don't work */
#define HDE 12             /*  poly(derivs of y) = f(x,y), linear in highest y-deriv */
                          /*  draws in both directions, direction fields don't work */
#define RELATION 13        /* graph a relation */
#define CONTOUR 14        /* contour_plot */
#define COMPLEX_CONTOUR 15
#define COMPAREDERIV 16
#define COMPAREDERIVS 17
#define RIEMANNSUMS 18
#define TRAPEZOIDRULE 19
#define SIMPSONSRULE 20
#define SPACECURVE 21
#define NONPARAMETRICSURFACE 22
#define POLARNONPARAMETRICSURFACE 23
#define PARAMETRICSURFACE 24

#define GRAPH3D(x)  (SPACECURVE <= (x) && (x) <= PARAMETRICSURFACE)