一個基礎的 switch 表達式由 switch 關鍵字開始，后面是開關的主題表達式，然后是大括號內的case 表達式。case 表達式都是以case 關鍵字開始，后跟一個模式表達式，還有一種 defalut 關鍵字定義默認行為。每個case 后都跟一個冒號和一個可選的case 體表達式： > A basic switch expression starts with the switch keyword and the switch subject expression, as well as the case expressions between curly braces {}. Case expressions either start with the case keyword and are followed by a pattern expression, or consist of the default keyword. In both cases a colon : and an optional case body expression follows: ~~~ switch subject { case pattern1: case-body-expression-1; case pattern2: case-body-expression-2; default: default-expression; } ~~~ case 體表達式從不失敗，所以 break（第5.20節）關鍵字在Haxe是不支持的。 > Case body expressions never “fall through”,sothe break (5.20) keyword is not supported in Haxe. switch 表達式可以用作一個值；這種情況，所有case體表達式的類型和default表達式的類型必須是統一的（第3.5節）。 > Switch expressions can be used as value; in that case the types of all case body expressions and the default expression must unify (3.5). 更多關于模式匹配表達式的語法細節，在模式匹配（第6.4節）中詳述。 > Further details on syntax of pattern expressions are detailed in Pattern Matching(Section6.4).