FormatGNU

	// Schily's tar format, which is incompatible with USTAR.
	// This does not cover STAR extensions to the PAX format; these fall under
	// the PAX format.
	formatSTAR

	formatMax
)

func (f Format) has(f2 Format) bool   { return f&f2 != 0 }
func (f *Format) mayBe(f2 Format)     { *f |= f2 }
func (f *Format) mayOnlyBe(f2 Format) { *f &= f2 }
func (f *Format) mustNotBe(f2 Format) { *f &^= f2 }

	fmtDebug
	fmtTypeID
	fmtTypeIDName
)

// Sym

// Format implements formatting for a Sym.
// The valid formats are:
//
//	%v	Go syntax: Name for symbols in the local package, PkgName.Name for imported symbols.
//	%+v	Debug syntax: always include PkgName. prefix even for local names.
//	%S	Short syntax: Name only, no matter what.
func (s *Sym) Format(f fmt.State, verb rune) {
	mode := fmtGo
	switch verb {
	case 'v', 'S':

	if int(o) < len(OpNames) && OpNames[o] != "" {
		return OpNames[o]
	}
	return o.String()
}

// Format implements formatting for an Op.
// The valid formats are:
//
//	%v	Go syntax ("+", "<-", "print")
//	%+v	Debug syntax ("ADD", "RECV", "PRINT")
func (o Op) Format(s fmt.State, verb rune) {
	switch verb {
	default:
		fmt.Fprintf(s, "%%!%c(Op=%d)", verb, int(o))
	case 'v':

// without running a subprocess. The log prefix will be added when
// logged in main; it is not added here.
func (pkg *Package) Fatalf(format string, args ...any) {
	panic(PackageError(fmt.Sprintf(format, args...)))
}

// parsePackage turns the build package we found into a parsed package
// we can then use to generate documentation.

		if cfg.BuildN {
			return nil
		}
	}
	return os.Symlink(oldname, newname)
}

// fmtCmd formats a command in the manner of fmt.Sprintf but also:
//
//	fmtCmd replaces the value of b.WorkDir with $WORK.
func (sh *Shell) fmtCmd(dir string, format string, args ...any) string {
	cmd := fmt.Sprintf(format, args...)
	if sh.workDir != "" && !strings.HasPrefix(cmd, "cat ") {
		cmd = strings.ReplaceAll(cmd, sh.workDir, "$WORK")

			wantFormat.mayBe(FormatUSTAR) // PAX implies USTAR allowed too
		}
		format.mayOnlyBe(wantFormat) // Set union of formats allowed and format wanted
	}
	if format == FormatUnknown {
		switch h.Format {
		case FormatUSTAR:
			err = headerError{"Format specifies USTAR", whyNoUSTAR, whyOnlyPAX, whyOnlyGNU}
		case FormatPAX:
			err = headerError{"Format specifies PAX", whyNoPAX, whyOnlyGNU}
		case FormatGNU:

		}
	}

	// Round ModTime and ignore AccessTime and ChangeTime unless
	// the format is explicitly chosen.
	// This ensures nominal usage of WriteHeader (without specifying the format)
	// does not always result in the PAX format being chosen, which
	// causes a 1KiB increase to every header.
	if tw.hdr.Format == FormatUnknown {
		tw.hdr.ModTime = tw.hdr.ModTime.Round(time.Second)
		tw.hdr.AccessTime = time.Time{}

	// x.expr may not be set if x is invalid
	if x.expr == nil {
		return nopos
	}
	return x.expr.Pos()
}

// Operand string formats
// (not all "untyped" cases can appear due to the type system,
// but they fall out naturally here)
//
// mode       format
//
// invalid    <expr> (               <mode>                    )
// novalue    <expr> (               <mode>                    )

			return true
		}
	}

	return false
}

// goodOSArchFile returns false if the name contains a $GOOS or $GOARCH
// suffix which does not match the current system.
// The recognized name formats are:
//
//	name_$(GOOS).*
//	name_$(GOARCH).*
//	name_$(GOOS)_$(GOARCH).*
//	name_$(GOOS)_test.*
//	name_$(GOARCH)_test.*
//	name_$(GOOS)_$(GOARCH)_test.*
//
// Exceptions:

The -go=version flag sets the expected Go language version.

The -toolchain=name flag sets the Go toolchain to use.

The -print flag prints the final go.work in its text format instead of
writing it back to go.mod.

The -json flag prints the final go.work file in JSON format instead of
writing it back to go.mod. The JSON output corresponds to these Go types:

	type GoWork struct {
		Go        string
		Toolchain string