canplay
if ((playit[i] = canplay(pp, op, card)) != 0)
if ((playit[i] = canplay(pp, op, card))
if ((playit[i] = canplay(pp, op, card))
playit[i] = canplay(pp, op, card);
int canplay(const PLAY *, const PLAY *, CARD);
if (is_safety(card) || canplay(pp, op, card)) {
fprintf(outf, "canplay(pp, op, card) = %d\n", canplay(pp, op, card));