void SN_set_current(struct SN_env * z, int size, const symbol * s) { replace_s(z, 0, z->l, size, s); z->c = 0; }
extern int SN_set_current(struct SN_env * z, int size, const symbol * s) { int err = replace_s(z, 0, z->l, size, s, NULL); z->c = 0; return err; }