Golang的Semicolons

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

Semicolons

The formal grammar uses semicolons ";" as terminators in a number of productions. Go programs may omit most of these semicolons using the following two rules:

1. When the input is broken into tokens, a semicolon is automatically inserted into the token stream at the end of a non-blank line if the line's final token is

   • an identifier
   • an integer, floating-point, imaginary, rune, or string literal
   • one of the keywords break, continue, fallthrough, or return
   • one of the operators and delimiters ++, --, ), ], or }

    

2. To allow complex statements to occupy a single line, a semicolon may be omitted before a closing ")" or "}".

To reflect idiomatic use, code examples in this document elide semicolons using these rules.

說得很清楚:

Golang編譯器自動在行尾插入分號(Semicolons):

    1. 關鍵字keywords

    2. 標識符identifiers

    3. 直接量Literals

    4. 某些運算子: ++, --, ), ], }

由於在初始化塊{...}中使用逗號而不是分號, 所以在塊內換行需要謹慎編譯器會自動插入分號.

像

var files = []struct { Name, Body string }{ {"readme.txt", "This archive contains some text files."}, {"gopher.txt","Gopher names:\nGeorge\nGeoffrey\nGonzo"}, {"todo.txt", "Get animal handling license."}

}

編譯時間會報錯, 原因是在最後一個元素後自動插入了分號, 解決辦法:

    1. 在最後一個元素後也加逗號

var files = []struct { Name, Body string }{ {"readme.txt", "This archive contains some text files."}, {"gopher.txt","Gopher names:\nGeorge\nGeoffrey\nGonzo"}, {"todo.txt", "Get animal handling license."},

}

    2. 最後"}"不換行

var files = []struct {

Name, Body string }{ {"readme.txt", "This archive contains some text files."}, {"gopher.txt", "Gophernames:\nGeorge\nGeoffrey\nGonzo"}, {"todo.txt", "Get animal handling license."}}