// the overall language version; the first release is "1.x.0".
// The distinction is important because the relative ordering is
//
//	1.21 < 1.21rc1 < 1.21.0
//
// meaning that Go 1.21rc1 and Go 1.21.0 will both handle go.mod files that
// say "go 1.21", but Go 1.21rc1 will not handle files that say "go 1.21.0".
func IsLang(x string) bool {
	return gover.IsLang(x)
}

// the overall language version; the first release is "1.x.0".
// The distinction is important because the relative ordering is
//
//	1.21 < 1.21rc1 < 1.21.0
//
// meaning that Go 1.21rc1 and Go 1.21.0 will both handle go.mod files that
// say "go 1.21", but Go 1.21rc1 will not handle files that say "go 1.21.0".
func IsLang(x string) bool {
	v := Parse(x)
	return v != Version{} && v.Patch == "" && v.Kind == "" && v.Pre == ""
}

// Malformed versions compare less than well-formed versions and equal to each other.
// The language version "1.21" compares less than the release candidate and eventual releases "1.21rc1" and "1.21.0".
func compare(x, y string) int {
	vx := parse(x)
	vy := parse(y)

	if c := cmpInt(vx.major, vy.major); c != 0 {
		return c
	}
	if c := cmpInt(vx.minor, vy.minor); c != 0 {
		return c
	}

// Invalid versions, including the empty string, compare less than
// valid versions and equal to each other.
// The language version "go1.21" compares less than the
// release candidate and eventual releases "go1.21rc1" and "go1.21.0".
func Compare(x, y string) int {
	return gover.Compare(stripGo(x), stripGo(y))
}

// IsValid reports whether the version x is valid.
func IsValid(x string) bool {
	return gover.IsValid(stripGo(x))

// Invalid versions, including the empty string, compare less than
// valid versions and equal to each other.
// The language version "go1.21" compares less than the
// release candidate and eventual releases "go1.21rc1" and "go1.21.0".
// Custom toolchain suffixes are ignored during comparison:
// "go1.21.0" and "go1.21.0-bigcorp" are equal.
func Compare(x, y string) int { return compare(stripGo(x), stripGo(y)) }

	Context *Context

	// GoVersion describes the accepted Go language version. The string must
	// start with a prefix of the form "go%d.%d" (e.g. "go1.20", "go1.21rc1", or
	// "go1.21.0") or it must be empty; an empty string disables Go language
	// version checks. If the format is invalid, invoking the type checker will
	// result in an error.
	GoVersion string

	Context *Context

	// GoVersion describes the accepted Go language version. The string must
	// start with a prefix of the form "go%d.%d" (e.g. "go1.20", "go1.21rc1", or
	// "go1.21.0") or it must be empty; an empty string disables Go language
	// version checks. If the format is invalid, invoking the type checker will
	// result in an error.
	GoVersion string

	Syntax     *Line
}

// A Go is the go statement.
type Go struct {
	Version string // "1.23"
	Syntax  *Line
}

// A Toolchain is the toolchain statement.
type Toolchain struct {
	Name   string // "go1.21rc1"
	Syntax *Line
}

// A Godebug is a single godebug key=value statement.
type Godebug struct {
	Key    string
	Value  string
	Syntax *Line
}

// An Exclude is a single exclude statement.

24BF          ; mapped                 ; 006A          # 1.1  CIRCLED LATIN CAPITAL LETTER J
24C0          ; mapped                 ; 006B          # 1.1  CIRCLED LATIN CAPITAL LETTER K
24C1          ; mapped                 ; 006C          # 1.1  CIRCLED LATIN CAPITAL LETTER L
24C2          ; mapped                 ; 006D          # 1.1  CIRCLED LATIN CAPITAL LETTER M