operator + method

dynamic operator +(Object o)

Implementation

operator +(Object o){
  switch(o){
    case NamedLine n:
      return this + n.expression;
    case (double, PxUnit) l:
      return this + Expression.literal(l);
    case LiteralGetter lg:
      return this + Expression.literalGetter(lg);
    case double p:
      return this + Expression.percent(p);
    case PercentGetter pg:
      return this + Expression.percentGetter(pg);
    case Expression e:
      if(literal != null || e.literal != null){
        return Expression((Size size)=>percentGetter(size) + e.percentGetter(size), (Size size){
          final a = literal?.call(size);
          final b = e.literal?.call(size);
          /// 单位相同或者只有一个值
          if(a?.$2 == b?.$2 || a == null || b == null){
            return (((a?.$1 ?? 0) + (b?.$1 ?? 0)), (a?.$2 ?? b?.$2)!);
          }else
          /// 单位里有 wpc 和 hpc 的统一到[w,h]pc
          if(a.$2 == PxUnit.wpc){
            return (a.$1 + pxUnitDoubleWidthPercentGetter(b)(size), PxUnit.wpc);
          }else
          if(a.$2 == PxUnit.hpc){
            return (a.$1 + pxUnitDoubleHeightPercentGetter(b)(size), PxUnit.hpc);
          }else
          if(b.$2 == PxUnit.wpc){
            return (pxUnitDoubleWidthPercentGetter(a)(size) + b.$1, PxUnit.wpc);
          }else
          if(b.$2 == PxUnit.hpc){
            return (pxUnitDoubleWidthPercentGetter(a)(size) + b.$1, PxUnit.hpc);
          /// 单位里没有 wpc 和 hpc 的统一到 px
          }else{
            return (pxUnitDoubleGetter(a)(size) + pxUnitDoubleGetter(b)(size), PxUnit.px);
          }
        });
      }else{
        return Expression((Size size)=>percentGetter(size) + e.percentGetter(size), null);
      }
  }
}