一个简单的问题！(100分)

[?]请帮忙解释一下下面类型定义代码的语法含义：
1. TfcCustomTreeView = class;

2. TfcItemState = (fcisSelected, fcisGrayed, fcisDisabled, fcisChecked,
fcisFocused, fcisDefault, fcisHot, fcisMarked, fcisIndeterminate);

3. TfcItemStates = set of TfcItemState;

4. TfcTVDrawTextEvent = procedure (TreeView: TfcCustomTreeview;
Node: TfcTreeNode; ARect: TRect; AItemState: TfcItemStates;
var DefaultDrawing: boolean) of object;

5. TfcNodeInfo = packed record
DummyPad: packed array[1..4] of char; { Allow Future growth }
Data: Pointer;
Text: string[255];
end;

1. TfcCustomTreeView = class;
>>定义一个类
2. TfcItemState = (fcisSelected, fcisGrayed, fcisDisabled, fcisChecked,
fcisFocused, fcisDefault, fcisHot, fcisMarked, fcisIndeterminate);
>>定义一个状态集的数据
3. TfcItemStates = set of TfcItemState;
>>定义一个状态集类型就是TfcItemStates
4. TfcTVDrawTextEvent = procedure (TreeView: TfcCustomTreeview;
Node: TfcTreeNode; ARect: TRect; AItemState: TfcItemStates;
var DefaultDrawing: boolean) of object;
>>定义一个过程
5. TfcNodeInfo = packed record
DummyPad: packed array[1..4] of char; { Allow Future growth }
Data: Pointer;
Text: string[255];
end;
>>定义一个纪录类型就是TfcNodeInfo

还是学习pascal基本语法先