/// <summary> /// 收集子标签。 /// </summary> /// <param name="tag">指定一个标签实例。</param> /// <param name="index">指定标签索引。</param> /// <returns>Tag</returns> private Tag CollectForTag(Tag tag, ref int index) { if (tag.IsClosed) return tag; if (string.Compare(tag.Name, "if", true) == 0) tag = new TagIf(tag.Line, tag.Col, tag.AttributeValue("test")); Tag collectTag = tag; for (index++; index < _Elements.Count; index++) { Element elem = _Elements[index]; if (elem is Text) collectTag.InnerElements.Add(elem); else if (elem is Expression) collectTag.InnerElements.Add(elem); else if (elem is Tag) { Tag innerTag = (Tag)elem; if (string.Compare(innerTag.Name, "else", true) == 0) { if (collectTag is TagIf) { ((TagIf)collectTag).FalseBranch = innerTag; collectTag = innerTag; } else throw new ParseException("else 标签必须包含在 if 或 elseif 之内。", innerTag.Line, innerTag.Col); } else if (string.Compare(innerTag.Name, "elseif", true) == 0) { if (collectTag is TagIf) { Tag newTag = new TagIf(innerTag.Line, innerTag.Col, innerTag.AttributeValue("test")); ((TagIf)collectTag).FalseBranch = newTag; collectTag = newTag; } else throw new ParseException("elseif 标签位置不正确。", innerTag.Line, innerTag.Col); } else collectTag.InnerElements.Add(CollectForTag(innerTag, ref index)); } else if (elem is TagClose) { TagClose tagClose = (TagClose)elem; if (string.Compare(tag.Name, tagClose.Name, true) == 0) return tag; throw new ParseException("没有为闭合标签 " + tagClose.Name + " 找到合适的开始标签。", elem.Line, elem.Col); } else throw new ParseException("无效标签: " + elem.GetType().ToString(), elem.Line, elem.Col); } throw new ParseException("没有为开始标签 " + tag.Name + " 找到合适的闭合标签。", tag.Line, tag.Col); }
/// <summary> /// 处理 If 语句。 /// </summary> /// <param name="tagIf">包含 if 语句的标签实例。</param> protected void ProcessIf(TagIf tagIf) { bool condition = false; try { object value = this.EvalExpression(tagIf.Test); condition = Utility.ToBool(value); } catch (Exception ex) { this.DisplayError("遭遇非法的 If 语句。" + ex.Message, tagIf.Line, tagIf.Col); return; } if (condition) this.ProcessElements(tagIf.InnerElements); else this.ProcessElement(tagIf.FalseBranch); }