Function defaults

src/compute-engine/rubi/match.ts:157–161

(i: number, kk: () => boolean)

          if (mSeq(pat.ops, expr.ops, x, env, k)) return true;
        }
      }
      // Collapse: default away the optional operands and match the single
      // remaining operand against the whole expression.
      return mCollapse(pat, expr, x, env, k);
    }
  }
}