This article will introduce keywords and identifiers in Go.
Keywords are the special words which help compilers understand and parse user code.
Up to now (Go 1.20), Go has only 25 keywords:break default func interface select
case defer go map struct
chan else goto package switch
const fallthrough if range type
continue for import return var
const, func, import, package, type and var
are used to declare all kinds of code elements in Go programs.
chan, interface, map and struct
are used as parts in some composite type denotations.
break, case, continue, default, else, fallthrough,
for, goto, if, range, return, select and switch
are used to control flow of code.
defer and go are also control flow keywords, but in other specific manners.
They modify function calls, which we'll talk about in
this article.
These keywords will be explained in details in other articles.
_ (underscore), and start with
either an Unicode letter or _.
Here,
keywords can not be used as identifiers.
Identifier _ is a special identifier, it is called blank identifier.
Later we will learn that all names of types, variables, constants, labels, package names and package import names must be identifiers.
An identifier starting with an Unicode upper case letter is called an exported identifier. The word exported can be interpreted as public in many other languages. The identifiers which don't start with an Unicode upper case letter are called non-exported identifiers. The word non-exported can be interpreted as private in many other languages. Currently (Go 1.20), eastern characters are viewed as non-exported letters. Sometimes, non-exported identifiers are also called unexported identifiers.
Player_9
DoSomething
VERSION
Ĝo
Π
_
_status
memStat
book
π
一个类型
변수
エラー
// Starting with a Unicode digit.
123
3apples
// Containing Unicode characters not
// satisfying the requirements.
a.b
*ptr
$name
a@b.c
// These are keywords.
type
range
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