Golang的Semicolons

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.

说得很清楚:

Golang编译器自动在行尾插入分号(Semicolons):

1. 关键字keywords

2. 标识符identifiers

3. 直接量Literals

4. 某些运算符: ++, --, ), ], }

由于在初始化块{...}中使用逗号而不是分号, 所以在块内换行需要谨慎编译器会自动插入分号.

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."}

}

编译时会报错, 原因是在最后一个元素后自动插入了分号, 解决办法:

1. 在最后一个元素后也加逗号

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. 最后"}"不换行

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."}}