Ada無約束類型

Question

你好我新來ada和我想創建一種不受約束的數組，我不知道如何在ada中做到這一點。

package data_puzzle is 
    type rotation is private; 
    type map(x_l,y_l,z_l : Natural) is private; 
    type valid_rotations is private; 
private 
    type rotation is array(1..3) of Natural; 
    type map(x_l,y_l,z_l : Natural) is record 
     struct : Structure(x_l,y_l,z_l); 
     rot : rotation; 
    end record; 

    type valid_rotations is array(1..24) of map; --how can I make this row work? 
end data_puzzle; 

結構看起來像這樣

type structure(x_l,y_l,z_l : Natural) is record 
    structure : xyz(1..x_l,1..y_l,1..z_l); 
    X : Natural := x_l; 
    Y : Natural := y_l; 
    Z : Natural := z_l; 
end record; 

基本上我有一個旋轉和數據的地圖。然後我想將所有不同的旋轉存儲在大小爲24的列表中。我現在唯一的解決方案是啓動 類型valid_rotations是map（x，y，z）的數組（1..24），然後它可以工作。但我不想這樣做，因爲我不知道那個時候尺寸會是多少。

乾杯！

Answer 1

好的，問題是，類型map可以是不同的大小 - 編譯器因此不能簡單地留出適當數量的內存W/O進一步的信息 - 所以解決方案是創建某種間接的可以是一個數組的元素：我們有這種類型，因爲Ada 83 但是與Ada 2005，我們可以進一步限制訪問類型爲空。

-- I don't know what this is supposed to be; I'm assuming an array. 
type xyz is Array(Positive Range <>, Positive Range <>, Positive Range <>) 
    of Integer; 

type structure(x_l,y_l,z_l : Natural) is record 
structure : xyz(1..x_l,1..y_l,1..z_l); 
X : Natural := x_l; 
Y : Natural := y_l; 
Z : Natural := z_l; 
end record; 

package data_puzzle is 
type rotation is private; 
type map(x_l,y_l,z_l : Natural) is private; 
type valid_rotations is private; 

type map_handle is private; 
private 
type rotation is array(1..3) of Natural; 
type map(x_l,y_l,z_l : Natural) is record 
    struct : Structure(x_l,y_l,z_l); 
    rot : rotation; 
end record; 

-- Because the size of the record "map" can change 
-- depending on its discriminants, we cannot simply 
-- make some array -- we can however have an array 
-- of accesses (since we know their sizes at compile) 
-- and constrain these access-types to be non-null. 
type valid_rotations is array(1..24) of map_handle; 

-- Here it is: an access which cannot be null. 
type map_handle is Not Null Access Map; 

end data_puzzle; 

另外，我想刪除的判別的_1（X，Y，Z）看起來沒什麼問題。