func (v *Variable) setValue(y *Variable) error {
	var err error
	switch v.Kind {
	case reflect.Float32, reflect.Float64:
		f, _ := constant.Float64Val(y.Value)
		err = v.writeFloatRaw(f, v.RealType.Size())
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		n, _ := constant.Int64Val(y.Value)
		err = v.writeUint(uint64(n), v.RealType.Size())
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		n, _ := constant.Uint64Val(y.Value)
		err = v.writeUint(n, v.RealType.Size())
	case reflect.Bool:
		err = v.writeBool(constant.BoolVal(y.Value))
	case reflect.Complex64, reflect.Complex128:
		real, _ := constant.Float64Val(constant.Real(y.Value))
		imag, _ := constant.Float64Val(constant.Imag(y.Value))
		err = v.writeComplex(real, imag, v.RealType.Size())
	default:
		fmt.Printf("default\n")
		if t, isptr := v.RealType.(*dwarf.PtrType); isptr {
			err = v.writeUint(uint64(y.Children[0].Addr), int64(t.ByteSize))
		} else {
			return fmt.Errorf("can not set variables of type %s (not implemented)", v.Kind.String())
		}
	}

	return err
}

func (g *javaGen) genConst(o *types.Const) {
	// TODO(hyangah): should const names use upper cases + "_"?
	// TODO(hyangah): check invalid names.
	jType := g.javaType(o.Type())
	val := o.Val().String()
	switch b := o.Type().(*types.Basic); b.Kind() {
	case types.Int64, types.UntypedInt:
		i, exact := constant.Int64Val(o.Val())
		if !exact {
			g.errorf("const value %s for %s cannot be represented as %s", val, o.Name(), jType)
			return
		}
		val = fmt.Sprintf("%dL", i)

	case types.Float32:
		f, _ := constant.Float32Val(o.Val())
		val = fmt.Sprintf("%gf", f)

	case types.Float64, types.UntypedFloat:
		f, _ := constant.Float64Val(o.Val())
		if math.IsInf(f, 0) || math.Abs(f) > math.MaxFloat64 {
			g.errorf("const value %s for %s cannot be represented as %s", val, o.Name(), jType)
			return
		}
		val = fmt.Sprintf("%g", f)
	}
	g.Printf("public static final %s %s = %s;\n", g.javaType(o.Type()), o.Name(), val)
}

// goVal returns the Go value for val, or nil.
func goVal(val constant.Value) interface{} {
	// val should exist, but be conservative and check
	if val == nil {
		return nil
	}
	// Match implementation restriction of other compilers.
	// gc only checks duplicates for integer, floating-point
	// and string values, so only create Go values for these
	// types.
	switch val.Kind() {
	case constant.Int:
		if x, ok := constant.Int64Val(val); ok {
			return x
		}
		if x, ok := constant.Uint64Val(val); ok {
			return x
		}
	case constant.Float:
		if x, ok := constant.Float64Val(val); ok {
			return x
		}
	case constant.String:
		return constant.StringVal(val)
	}
	return nil
}

func roundFloat64(x exact.Value) exact.Value {
	f, _ := exact.Float64Val(x)
	if !math.IsInf(f, 0) {
		return exact.MakeFloat64(f)
	}
	return nil
}

// constValString emulates Go 1.6's go/constant.ExactString well enough
// to make the tests pass.  This is just a stopgap until we throw away
// all the *15.go files.
func constValString(v exact.Value) string {
	if v.Kind() == exact.Float {
		f, _ := exact.Float64Val(v)
		return fmt.Sprintf("%g", f)
	}
	return v.String()
}

func roundFloat64(x constant.Value) constant.Value {
	f, _ := constant.Float64Val(x)
	if !math.IsInf(f, 0) {
		return constant.MakeFloat64(f)
	}
	return nil
}

// Helper function to adjust go1.5 numeric go/constant formatting.
// Can be removed once we give up compatibility with go1.5.
func constValString(v exact.Value) string {
	if v.Kind() == exact.Float {
		// In go1.5, go/constant floating-point values are printed
		// as fractions. Make them appear as floating-point numbers.
		f, _ := exact.Float64Val(v)
		return fmt.Sprintf("%g", f)
	}
	return v.String()
}

func ConvertVar(v *proc.Variable) *Variable {
	r := Variable{
		Addr: v.Addr,
		Name: v.Name,
		Kind: v.Kind,
		Len:  v.Len,
		Cap:  v.Cap,
	}

	if v.DwarfType != nil {
		r.Type = v.DwarfType.String()
	}

	if v.RealType != nil {
		r.RealType = v.RealType.String()
	}

	if v.Unreadable != nil {
		r.Unreadable = v.Unreadable.Error()
	}

	if v.Value != nil {
		switch v.Kind {
		case reflect.Float32:
			f, _ := constant.Float64Val(v.Value)
			r.Value = strconv.FormatFloat(f, 'f', -1, 32)
		case reflect.Float64:
			f, _ := constant.Float64Val(v.Value)
			r.Value = strconv.FormatFloat(f, 'f', -1, 64)
		case reflect.String, reflect.Func:
			r.Value = constant.StringVal(v.Value)
		default:
			r.Value = v.Value.String()
		}
	}

	r.Children = make([]Variable, len(v.Children))

	for i := range v.Children {
		r.Children[i] = *ConvertVar(&v.Children[i])
	}

	return &r
}

// Uint64 returns the numeric value of this constant truncated to fit
// an unsigned 64-bit integer.
//
func (c *Const) Uint64() uint64 {
	switch x := c.Value; x.Kind() {
	case exact.Int:
		if u, ok := exact.Uint64Val(x); ok {
			return u
		}
		return 0
	case exact.Float:
		f, _ := exact.Float64Val(x)
		return uint64(f)
	}
	panic(fmt.Sprintf("unexpected constant value: %T", c.Value))
}

// Int64 returns the numeric value of this constant truncated to fit
// a signed 64-bit integer.
//
func (c *Const) Int64() int64 {
	switch x := exact.ToInt(c.Value); x.Kind() {
	case exact.Int:
		if i, ok := exact.Int64Val(x); ok {
			return i
		}
		return 0
	case exact.Float:
		f, _ := exact.Float64Val(x)
		return int64(f)
	}
	panic(fmt.Sprintf("unexpected constant value: %T", c.Value))
}

func (g *ObjcGen) genConstM(o *types.Const) {
	if _, ok := o.Type().(*types.Basic); !ok {
		g.Printf("// skipped const %s with unsupported type: %T\n\n", o.Name(), o)
		return
	}
	cName := fmt.Sprintf("%s%s", g.namePrefix, o.Name())
	objcType := g.objcType(o.Type())

	switch b := o.Type().(*types.Basic); b.Kind() {
	case types.Bool, types.UntypedBool:
		v := "NO"
		if constant.BoolVal(o.Val()) {
			v = "YES"
		}
		g.Printf("const BOOL %s = %s;\n", cName, v)

	case types.String, types.UntypedString:
		g.Printf("NSString* const %s = @%s;\n", cName, constExactString(o))

	case types.Int, types.Int8, types.Int16, types.Int32:
		g.Printf("const %s %s = %s;\n", objcType, cName, o.Val())

	case types.Int64, types.UntypedInt:
		i, exact := constant.Int64Val(o.Val())
		if !exact {
			g.errorf("const value %s for %s cannot be represented as %s", o.Val(), o.Name(), objcType)
			return
		}
		if i == math.MinInt64 {
			// -9223372036854775808LL does not work because 922337203685477508 is
			// larger than max int64.
			g.Printf("const int64_t %s = %dLL-1;\n", cName, i+1)
		} else {
			g.Printf("const int64_t %s = %dLL;\n", cName, i)
		}

	case types.Float32, types.Float64, types.UntypedFloat:
		f, _ := constant.Float64Val(o.Val())
		if math.IsInf(f, 0) || math.Abs(f) > math.MaxFloat64 {
			g.errorf("const value %s for %s cannot be represented as double", o.Val(), o.Name())
			return
		}
		g.Printf("const %s %s = %g;\n", objcType, cName, f)

	default:
		g.errorf("unsupported const type %s for %s", b, o.Name())
	}
}

func (p *exporter) float(x constant.Value) {
	if x.Kind() != constant.Float {
		log.Fatalf("gcimporter: unexpected constant %v, want float", x)
	}
	// extract sign (there is no -0)
	sign := constant.Sign(x)
	if sign == 0 {
		// x == 0
		p.int(0)
		return
	}
	// x != 0

	var f big.Float
	if v, exact := constant.Float64Val(x); exact {
		// float64
		f.SetFloat64(v)
	} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
		// TODO(gri): add big.Rat accessor to constant.Value.
		r := valueToRat(num)
		f.SetRat(r.Quo(r, valueToRat(denom)))
	} else {
		// Value too large to represent as a fraction => inaccessible.
		// TODO(gri): add big.Float accessor to constant.Value.
		f.SetFloat64(math.MaxFloat64) // FIXME
	}

	// extract exponent such that 0.5 <= m < 1.0
	var m big.Float
	exp := f.MantExp(&m)

	// extract mantissa as *big.Int
	// - set exponent large enough so mant satisfies mant.IsInt()
	// - get *big.Int from mant
	m.SetMantExp(&m, int(m.MinPrec()))
	mant, acc := m.Int(nil)
	if acc != big.Exact {
		log.Fatalf("gcimporter: internal error")
	}

	p.int(sign)
	p.int(exp)
	p.string(string(mant.Bytes()))
}

// ResolveAsType implements the Constant interface.
func (expr *NumVal) ResolveAsType(typ Datum) (Datum, error) {
	switch {
	case typ.TypeEqual(TypeInt):
		i, exact := constant.Int64Val(constant.ToInt(expr.Value))
		if !exact {
			return nil, fmt.Errorf("integer value out of range: %v", expr.Value)
		}
		return NewDInt(DInt(i)), nil
	case typ.TypeEqual(TypeFloat):
		f, _ := constant.Float64Val(constant.ToFloat(expr.Value))
		return NewDFloat(DFloat(f)), nil
	case typ.TypeEqual(TypeDecimal):
		dd := &DDecimal{}
		s := expr.ExactString()
		if idx := strings.IndexRune(s, '/'); idx != -1 {
			// Handle constant.ratVal, which will return a rational string
			// like 6/7. If only we could call big.Rat.FloatString() on it...
			num, den := s[:idx], s[idx+1:]
			if _, ok := dd.SetString(num); !ok {
				return nil, fmt.Errorf("could not evaluate numerator of %v as Datum type DDecimal "+
					"from string %q", expr, num)
			}
			denDec := new(inf.Dec)
			if _, ok := denDec.SetString(den); !ok {
				return nil, fmt.Errorf("could not evaluate denominator %v as Datum type DDecimal "+
					"from string %q", expr, den)
			}
			dd.QuoRound(&dd.Dec, denDec, decimal.Precision, inf.RoundHalfUp)
		} else {
			if _, ok := dd.SetString(s); !ok {
				return nil, fmt.Errorf("could not evaluate %v as Datum type DDecimal from "+
					"string %q", expr, s)
			}
		}
		return dd, nil
	default:
		return nil, fmt.Errorf("could not resolve %T %v into a %T", expr, expr, typ)
	}
}

// Float64 returns the numeric value of this constant truncated to fit
// a float64.
//
func (c *Const) Float64() float64 {
	f, _ := exact.Float64Val(c.Value)
	return f
}

// ConvertVar converts from proc.Variable to api.Variable.
func ConvertVar(v *proc.Variable) *Variable {
	r := Variable{
		Addr:     v.Addr,
		OnlyAddr: v.OnlyAddr,
		Name:     v.Name,
		Kind:     v.Kind,
		Len:      v.Len,
		Cap:      v.Cap,
	}

	r.Type = prettyTypeName(v.DwarfType)
	r.RealType = prettyTypeName(v.RealType)

	if v.Unreadable != nil {
		r.Unreadable = v.Unreadable.Error()
	}

	if v.Value != nil {
		switch v.Kind {
		case reflect.Float32:
			f, _ := constant.Float64Val(v.Value)
			r.Value = strconv.FormatFloat(f, 'f', -1, 32)
		case reflect.Float64:
			f, _ := constant.Float64Val(v.Value)
			r.Value = strconv.FormatFloat(f, 'f', -1, 64)
		case reflect.String, reflect.Func:
			r.Value = constant.StringVal(v.Value)
		default:
			r.Value = v.Value.String()
		}
	}

	switch v.Kind {
	case reflect.Complex64:
		r.Children = make([]Variable, 2)
		r.Len = 2

		real, _ := constant.Float64Val(constant.Real(v.Value))
		imag, _ := constant.Float64Val(constant.Imag(v.Value))

		r.Children[0].Name = "real"
		r.Children[0].Kind = reflect.Float32
		r.Children[0].Value = strconv.FormatFloat(real, 'f', -1, 32)

		r.Children[1].Name = "imaginary"
		r.Children[1].Kind = reflect.Float32
		r.Children[1].Value = strconv.FormatFloat(imag, 'f', -1, 32)
	case reflect.Complex128:
		r.Children = make([]Variable, 2)
		r.Len = 2

		real, _ := constant.Float64Val(constant.Real(v.Value))
		imag, _ := constant.Float64Val(constant.Imag(v.Value))

		r.Children[0].Name = "real"
		r.Children[0].Kind = reflect.Float64
		r.Children[0].Value = strconv.FormatFloat(real, 'f', -1, 64)

		r.Children[1].Name = "imaginary"
		r.Children[1].Kind = reflect.Float64
		r.Children[1].Value = strconv.FormatFloat(imag, 'f', -1, 64)

	default:
		r.Children = make([]Variable, len(v.Children))

		for i := range v.Children {
			r.Children[i] = *ConvertVar(&v.Children[i])
		}
	}

	return &r
}

func TestVariableEvaluation(t *testing.T) {
	testcases := []struct {
		name        string
		st          reflect.Kind
		value       interface{}
		length, cap int64
		childrenlen int
	}{
		{"a1", reflect.String, "foofoofoofoofoofoo", 18, 0, 0},
		{"a11", reflect.Array, nil, 3, -1, 3},
		{"a12", reflect.Slice, nil, 2, 2, 2},
		{"a13", reflect.Slice, nil, 3, 3, 3},
		{"a2", reflect.Int, int64(6), 0, 0, 0},
		{"a3", reflect.Float64, float64(7.23), 0, 0, 0},
		{"a4", reflect.Array, nil, 2, -1, 2},
		{"a5", reflect.Slice, nil, 5, 5, 5},
		{"a6", reflect.Struct, nil, 2, 0, 2},
		{"a7", reflect.Ptr, nil, 1, 0, 1},
		{"a8", reflect.Struct, nil, 2, 0, 2},
		{"a9", reflect.Ptr, nil, 1, 0, 1},
		{"baz", reflect.String, "bazburzum", 9, 0, 0},
		{"neg", reflect.Int, int64(-1), 0, 0, 0},
		{"f32", reflect.Float32, float64(float32(1.2)), 0, 0, 0},
		{"c64", reflect.Complex64, complex128(complex64(1 + 2i)), 0, 0, 0},
		{"c128", reflect.Complex128, complex128(2 + 3i), 0, 0, 0},
		{"a6.Baz", reflect.Int, int64(8), 0, 0, 0},
		{"a7.Baz", reflect.Int, int64(5), 0, 0, 0},
		{"a8.Baz", reflect.String, "feh", 3, 0, 0},
		{"a8", reflect.Struct, nil, 2, 0, 2},
		{"i32", reflect.Array, nil, 2, -1, 2},
		{"b1", reflect.Bool, true, 0, 0, 0},
		{"b2", reflect.Bool, false, 0, 0, 0},
		{"f", reflect.Func, "main.barfoo", 0, 0, 0},
		{"ba", reflect.Slice, nil, 200, 200, 64},
	}

	withTestProcess("testvariables", t, func(p *Process, fixture protest.Fixture) {
		assertNoError(p.Continue(), t, "Continue() returned an error")

		for _, tc := range testcases {
			v, err := evalVariable(p, tc.name)
			assertNoError(err, t, fmt.Sprintf("EvalVariable(%s)", tc.name))

			if v.Kind != tc.st {
				t.Fatalf("%s simple type: expected: %s got: %s", tc.name, tc.st, v.Kind.String())
			}
			if v.Value == nil && tc.value != nil {
				t.Fatalf("%s value: expected: %v got: %v", tc.name, tc.value, v.Value)
			} else {
				switch v.Kind {
				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
					x, _ := constant.Int64Val(v.Value)
					if y, ok := tc.value.(int64); !ok || x != y {
						t.Fatalf("%s value: expected: %v got: %v", tc.name, tc.value, v.Value)
					}
				case reflect.Float32, reflect.Float64:
					x, _ := constant.Float64Val(v.Value)
					if y, ok := tc.value.(float64); !ok || x != y {
						t.Fatalf("%s value: expected: %v got: %v", tc.name, tc.value, v.Value)
					}
				case reflect.Complex64, reflect.Complex128:
					xr, _ := constant.Float64Val(constant.Real(v.Value))
					xi, _ := constant.Float64Val(constant.Imag(v.Value))
					if y, ok := tc.value.(complex128); !ok || complex(xr, xi) != y {
						t.Fatalf("%s value: expected: %v got: %v", tc.name, tc.value, v.Value)
					}
				case reflect.String:
					if y, ok := tc.value.(string); !ok || constant.StringVal(v.Value) != y {
						t.Fatalf("%s value: expected: %v got: %v", tc.name, tc.value, v.Value)
					}
				}
			}
			if v.Len != tc.length {
				t.Fatalf("%s len: expected: %d got: %d", tc.name, tc.length, v.Len)
			}
			if v.Cap != tc.cap {
				t.Fatalf("%s cap: expected: %d got: %d", tc.name, tc.cap, v.Cap)
			}
			if len(v.Children) != tc.childrenlen {
				t.Fatalf("%s children len: expected %d got: %d", tc.name, tc.childrenlen, len(v.Children))
			}
		}
	})
}

func (c *funcContext) translateExpr(expr ast.Expr) *expression {
	exprType := c.p.TypeOf(expr)
	if value := c.p.Types[expr].Value; value != nil {
		basic := exprType.Underlying().(*types.Basic)
		switch {
		case isBoolean(basic):
			return c.formatExpr("%s", strconv.FormatBool(constant.BoolVal(value)))
		case isInteger(basic):
			if is64Bit(basic) {
				if basic.Kind() == types.Int64 {
					d, ok := constant.Int64Val(constant.ToInt(value))
					if !ok {
						panic("could not get exact uint")
					}
					return c.formatExpr("new %s(%s, %s)", c.typeName(exprType), strconv.FormatInt(d>>32, 10), strconv.FormatUint(uint64(d)&(1<<32-1), 10))
				}
				d, ok := constant.Uint64Val(constant.ToInt(value))
				if !ok {
					panic("could not get exact uint")
				}
				return c.formatExpr("new %s(%s, %s)", c.typeName(exprType), strconv.FormatUint(d>>32, 10), strconv.FormatUint(d&(1<<32-1), 10))
			}
			d, ok := constant.Int64Val(constant.ToInt(value))
			if !ok {
				panic("could not get exact int")
			}
			return c.formatExpr("%s", strconv.FormatInt(d, 10))
		case isFloat(basic):
			f, _ := constant.Float64Val(value)
			return c.formatExpr("%s", strconv.FormatFloat(f, 'g', -1, 64))
		case isComplex(basic):
			r, _ := constant.Float64Val(constant.Real(value))
			i, _ := constant.Float64Val(constant.Imag(value))
			if basic.Kind() == types.UntypedComplex {
				exprType = types.Typ[types.Complex128]
			}
			return c.formatExpr("new %s(%s, %s)", c.typeName(exprType), strconv.FormatFloat(r, 'g', -1, 64), strconv.FormatFloat(i, 'g', -1, 64))
		case isString(basic):
			return c.formatExpr("%s", encodeString(constant.StringVal(value)))
		default:
			panic("Unhandled constant type: " + basic.String())
		}
	}

	var obj types.Object
	switch e := expr.(type) {
	case *ast.SelectorExpr:
		obj = c.p.Uses[e.Sel]
	case *ast.Ident:
		obj = c.p.Defs[e]
		if obj == nil {
			obj = c.p.Uses[e]
		}
	}

	if obj != nil && typesutil.IsJsPackage(obj.Pkg()) {
		switch obj.Name() {
		case "Global":
			return c.formatExpr("$global")
		case "Module":
			return c.formatExpr("$module")
		case "Undefined":
			return c.formatExpr("undefined")
		}
	}

	switch e := expr.(type) {
	case *ast.CompositeLit:
		if ptrType, isPointer := exprType.(*types.Pointer); isPointer {
			exprType = ptrType.Elem()
		}

		collectIndexedElements := func(elementType types.Type) []string {
			var elements []string
			i := 0
			zero := c.translateExpr(c.zeroValue(elementType)).String()
			for _, element := range e.Elts {
				if kve, isKve := element.(*ast.KeyValueExpr); isKve {
					key, ok := constant.Int64Val(constant.ToInt(c.p.Types[kve.Key].Value))
					if !ok {
						panic("could not get exact int")
					}
					i = int(key)
					element = kve.Value
				}
				for len(elements) <= i {
					elements = append(elements, zero)
				}
				elements[i] = c.translateImplicitConversionWithCloning(element, elementType).String()
				i++
			}
			return elements
		}

		switch t := exprType.Underlying().(type) {
		case *types.Array:
			elements := collectIndexedElements(t.Elem())
			if len(elements) == 0 {
				return c.formatExpr("%s.zero()", c.typeName(t))
			}
//.........这里部分代码省略.........

//.........这里部分代码省略.........
		if val := c.p.Types[e.(ast.Expr)].Value; val != nil {
			continue
		}
		if !hasAssignments {
			hasAssignments = true
			out.WriteByte('(')
			parens = false
		}
		v := c.newVariable("x")
		out.WriteString(v + " = " + c.translateExpr(e.(ast.Expr)).String() + ", ")
		vars[i] = v
	}

	processFormat(func(b, k uint8, n int) {
		writeExpr := func(suffix string) {
			if vars[n] != "" {
				out.WriteString(vars[n] + suffix)
				return
			}
			out.WriteString(c.translateExpr(a[n].(ast.Expr)).StringWithParens() + suffix)
		}
		switch k {
		case 0:
			out.WriteByte(b)
		case 's':
			if e, ok := a[n].(*expression); ok {
				out.WriteString(e.StringWithParens())
				return
			}
			out.WriteString(a[n].(string))
		case 'd':
			out.WriteString(strconv.Itoa(a[n].(int)))
		case 't':
			out.WriteString(a[n].(token.Token).String())
		case 'e':
			e := a[n].(ast.Expr)
			if val := c.p.Types[e].Value; val != nil {
				out.WriteString(c.translateExpr(e).String())
				return
			}
			writeExpr("")
		case 'f':
			e := a[n].(ast.Expr)
			if val := c.p.Types[e].Value; val != nil {
				d, _ := constant.Int64Val(constant.ToInt(val))
				out.WriteString(strconv.FormatInt(d, 10))
				return
			}
			if is64Bit(c.p.TypeOf(e).Underlying().(*types.Basic)) {
				out.WriteString("$flatten64(")
				writeExpr("")
				out.WriteString(")")
				return
			}
			writeExpr("")
		case 'h':
			e := a[n].(ast.Expr)
			if val := c.p.Types[e].Value; val != nil {
				d, _ := constant.Uint64Val(constant.ToInt(val))
				if c.p.TypeOf(e).Underlying().(*types.Basic).Kind() == types.Int64 {
					out.WriteString(strconv.FormatInt(int64(d)>>32, 10))
					return
				}
				out.WriteString(strconv.FormatUint(d>>32, 10))
				return
			}
			writeExpr(".$high")
		case 'l':
			if val := c.p.Types[a[n].(ast.Expr)].Value; val != nil {
				d, _ := constant.Uint64Val(constant.ToInt(val))
				out.WriteString(strconv.FormatUint(d&(1<<32-1), 10))
				return
			}
			writeExpr(".$low")
		case 'r':
			if val := c.p.Types[a[n].(ast.Expr)].Value; val != nil {
				r, _ := constant.Float64Val(constant.Real(val))
				out.WriteString(strconv.FormatFloat(r, 'g', -1, 64))
				return
			}
			writeExpr(".$real")
		case 'i':
			if val := c.p.Types[a[n].(ast.Expr)].Value; val != nil {
				i, _ := constant.Float64Val(constant.Imag(val))
				out.WriteString(strconv.FormatFloat(i, 'g', -1, 64))
				return
			}
			writeExpr(".$imag")
		case '%':
			out.WriteRune('%')
		default:
			panic(fmt.Sprintf("formatExpr: %%%c%d", k, n))
		}
	})

	if hasAssignments {
		out.WriteByte(')')
	}
	return &expression{str: out.String(), parens: parens}
}

func fitsFloat64(x exact.Value) bool {
	f, _ := exact.Float64Val(x)
	return !math.IsInf(f, 0)
}

func fitsFloat64(x constant.Value) bool {
	f, _ := constant.Float64Val(x)
	return !math.IsInf(f, 0)
}