<!--{
	"Title": "The Go Programming Language Specification",
	"Subtitle": "Language version go1.26 (Dec 2, 2025)",
	"Path": "/ref/spec"
}-->

<h2 id="Introduction">Introduction</h2>

<p>
This is the reference manual for the Go programming language.
For more information and other documents, see <a href="/">go.dev</a>.
</p>

<p>
Go is a general-purpose language designed with systems programming

pkg go/build/constraint, type AndExpr struct, X Expr
pkg go/build/constraint, type AndExpr struct, Y Expr
pkg go/build/constraint, type Expr interface, Eval(func(string) bool) bool
pkg go/build/constraint, type Expr interface, String() string
pkg go/build/constraint, type Expr interface, unexported methods
pkg go/build/constraint, type NotExpr struct
pkg go/build/constraint, type NotExpr struct, X Expr
pkg go/build/constraint, type OrExpr struct

pkg errors, func Is(error, error) bool
pkg errors, func Unwrap(error) error
pkg go/constant, func Make(interface{}) Value
pkg go/constant, func Val(Value) interface{}
pkg go/token, func IsExported(string) bool
pkg go/token, func IsIdentifier(string) bool
pkg go/token, func IsKeyword(string) bool
pkg go/types, func CheckExpr(*token.FileSet, *Package, token.Pos, ast.Expr, *Info) error
pkg log, func Writer() io.Writer