Haxe中的一個塊由一個開口的 花括號 { 開始，以一個閉口的花括號 }結束。一個塊可以包含一些表達式，每個使用分號結束。通常的語法是： > A block in Haxe starts with an opening curly brace { and ends with a closing curly brace }. A block may contain several expressions, each of which is followed by a semicolon ;. The general syntax is thus: ~~~ { expr1; expr2; ... exprN; } ~~~ 值和被塊表達式擴展的類型等于值和最后一個子表達式的類型。 > The value and by extension the type of a block-expression is equal to the value and the type of the last sub-expression. 塊可以包含局部變量，通過 var表達式（第5.10節）聲明，同樣，局部函數通過 function 表達式（第5.11節）聲明。它們在塊和子塊中中是可用的，但是不能在塊的范圍之外使用。同樣，只有在被聲明之后才可以使用。下面的例子使用 var，但是同樣個規則應用到 function的用法： > Blocks can contain local variables declared by var expression (5.10), as well as local functions declared by function expressions (5.11). These are available within the block and within sub-blocks, but not outside the block. Also, they are available only after their declaration. The following example uses var, but the same rules apply to function usage: ~~~ { a; // error, a is not declared yet var a = 1; // declare a a; // ok, a was declared { a; // ok, a is available in sub-blocks } // ok, a is still available after // sub-blocks a; } a; // error, a is not available outside ~~~ 在運行時，塊從頭至尾執行。控制流（如異常（第5.18節）或者返回表達式（第5.19節））可能在所有的表達式被執行之前離開塊。 > At runtime, blocks are evaluated from top to bottom. Control ?ow (e.g. exceptions (5.18) or return expressions (5.19)) may leave a block before all expressions are evaluated.