e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
e_sqrt, e_not, e_random, e_hypot, e_gcd,
e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
+ e_sgn,
} type;
double value; // is sign in other types
union {
case e_ceil : return e->value * ceil (eval_expr(p, e->param[0]));
case e_trunc: return e->value * trunc(eval_expr(p, e->param[0]));
case e_round: return e->value * round(eval_expr(p, e->param[0]));
+ case e_sgn: return e->value * FFDIFFSIGN(eval_expr(p, e->param[0]), 0);
case e_sqrt: return e->value * sqrt (eval_expr(p, e->param[0]));
case e_not: return e->value * (eval_expr(p, e->param[0]) == 0);
case e_if: return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
else if (strmatch(next, "clip" )) d->type = e_clip;
else if (strmatch(next, "atan2" )) d->type = e_atan2;
else if (strmatch(next, "lerp" )) d->type = e_lerp;
+ else if (strmatch(next, "sgn" )) d->type = e_sgn;
else {
for (i=0; p->func1_names && p->func1_names[i]; i++) {
if (strmatch(next, p->func1_names[i])) {
case e_sqrt:
case e_not:
case e_random:
+ case e_sgn:
return verify_expr(e->param[0]) && !e->param[1];
case e_print:
return verify_expr(e->param[0])