Block functions are functions of the form: {func} .. {/func}. In other words, they enclose a template block and operate on the contents of this block. Block functions take precedence over custom functions of the same name, that is, you cannot have both custom function {func} and block function {func} .. {/func}.
塊函數的形式是這樣的：{func} .. {/func}。換句話說，他們用標記圈起一個塊，然後對這個塊的內容進行操作。塊函數優先於同名的傳統函數，即你不能同時有通明的傳統函數{func}和塊函數{func} .. {/func}。
By default your function implementation is called twice by Smarty: once for the opening tag, and once for the closing tag (see &$repeat below how to change this).
默認地你的函數執行被Smarty調用兩次：一次是在開始標記，另一次是在結束標記（參考下面的&$repeat怎樣改變這種情況）
Only the opening tag of the block function may have attributes. All attributes passed to template functions from the template are contained in the $params as an associative array. You can either access those values directly, e.g. $params['start'] or use extract($params) to import them into the symbol table. The opening tag attributes are also accessible to your function when processing the closing tag.
塊函數僅開始標記可以有屬性。所有從模板傳替給模板函數的屬性被囊括與一個集合數組參數中。你可以直接獲取其值，例如：$params['start']或者是用extract($params)將它們導入符號表中。當處理結束標記時，開始標記的屬性對你的函數也是可用的。
The value of $content variable depends on whether your function is called for the opening or closing tag. In case of the opening tag, it will be null, and in case of the closing tag it will be the contents of the template block. Note that the template block will have already been processed by Smarty, so all you will receive is the template output, not the template source.
變量$content的值取決於是否因開始標記或結束標記調用你的函數。假如是開始標記，它會是空的，如果是結束標記，它會是模板塊的內容。請注意模板塊已經被Smarty處理,所以你接收到的結果是輸出後的模板而不是原樣模板。
The parameter &$repeat is passed by reference to the function implementation and provides a possibility for it to control how many times the block is displayed. By default $repeat is true at the first call of the block-function (the block opening tag) and false on all subsequent calls to the block function (the block's closing tag). Each time the function implementation returns with &$repeat being true, the contents between {func} .. {/func} are evaluated and the function implementation is called again with the new block contents in the parameter $content.
參數&$repeat通過參考引用傳遞給函數執行過程併爲其提供一個可能值來控制顯示塊多少遍。默認情況下在首次調用塊函數（塊開始標記）時變量$repeat是真，在隨後的所有塊函數調用中其始終是假。每當函數執行返回的&$repeat是真時，在{func} .. {/func}之間的內容再次求值,函數執行接收一個新塊參數$content內容值被再次調用。
If you have nested block functions, it's possible to find out what the parent block function is by accessing $smarty->_tag_stack variable. Just do a var_dump() on it and the structure should be apparent.
如果你嵌套了塊函數，通過訪問變量$smarty->_tag_stack 找出父塊函數是可能的。僅僅對塊函數運行一下var_dump()，函數結構就會一目瞭然了。
See also: register_block(), unregister_block().