/* Definitions of built in constraints */
Tc(Tcnum,	"numeric")      /* arith ops */
Tc(Tcint,	"integral")     /* behaves like an int, defaults to int as fallback */
Tc(Tcflt,	"floating")     /* behaves like a float, defaults to float as fallback */
Tc(Tcidx,	"indexable")    /* indexable */
Tc(Tcslice,	"sliceable")    /* sliceable */
Tc(Tcfunc,	"function")     /* behaves like a function */
Tc(Tciter,	"iterable")     /* can be iterated over */
Tc(Tcdisp,	"disposable")   /* automatically disposable */
