// zeroConst returns a new "zero" constant of the specified type,
// which must not be an array or struct type: the zero values of
// aggregates are well-defined but cannot be represented by Const.
//
func zeroConst(t types.Type) *Const {
switch t := t.(type) {
case *types.Basic:
switch {
case t.Info()&types.IsBoolean != 0:
return NewConst(exact.MakeBool(false), t)
case t.Info()&types.IsNumeric != 0:
return NewConst(exact.MakeInt64(0), t)
case t.Info()&types.IsString != 0:
return NewConst(exact.MakeString(""), t)
case t.Kind() == types.UnsafePointer:
fallthrough
case t.Kind() == types.UntypedNil:
return nilConst(t)
default:
panic(fmt.Sprint("zeroConst for unexpected type:", t))
}
case *types.Pointer, *types.Slice, *types.Interface, *types.Chan, *types.Map, *types.Signature:
return nilConst(t)
case *types.Named:
return NewConst(zeroConst(t.Underlying()).Value, t)
case *types.Array, *types.Struct, *types.Tuple:
panic(fmt.Sprint("zeroConst applied to aggregate:", t))
}
panic(fmt.Sprint("zeroConst: unexpected ", t))
}
// number = int_lit [ "p" int_lit ] .
//
func (p *gcParser) parseNumber() (x operand) {
x.mode = constant
// mantissa
mant := exact.MakeFromLiteral(p.parseInt(), token.INT)
assert(mant != nil)
if p.lit == "p" {
// exponent (base 2)
p.next()
exp, err := strconv.ParseInt(p.parseInt(), 10, 0)
if err != nil {
p.error(err)
}
if exp < 0 {
denom := exact.MakeInt64(1)
denom = exact.Shift(denom, token.SHL, uint(-exp))
x.typ = Typ[UntypedFloat]
x.val = exact.BinaryOp(mant, token.QUO, denom)
return
}
if exp > 0 {
mant = exact.Shift(mant, token.SHL, uint(exp))
}
x.typ = Typ[UntypedFloat]
x.val = mant
return
}
x.typ = Typ[UntypedInt]
x.val = mant
return
}
// number = int_lit [ "p" int_lit ] .
//
func (p *parser) parseNumber() (typ *types.Basic, val exact.Value) {
// mantissa
mant := exact.MakeFromLiteral(p.parseInt(), token.INT)
if mant == nil {
panic("invalid mantissa")
}
if p.lit == "p" {
// exponent (base 2)
p.next()
exp, err := strconv.ParseInt(p.parseInt(), 10, 0)
if err != nil {
p.error(err)
}
if exp < 0 {
denom := exact.MakeInt64(1)
denom = exact.Shift(denom, token.SHL, uint(-exp))
typ = types.Typ[types.UntypedFloat]
val = exact.BinaryOp(mant, token.QUO, denom)
return
}
if exp > 0 {
mant = exact.Shift(mant, token.SHL, uint(exp))
}
typ = types.Typ[types.UntypedFloat]
val = mant
return
}
typ = types.Typ[types.UntypedInt]
val = mant
return
}
func (p *importer) ufloat() exact.Value {
exp := p.int()
x := exact.MakeFromBytes(p.bytes())
switch {
case exp < 0:
d := exact.Shift(exact.MakeInt64(1), token.SHL, uint(-exp))
x = exact.BinaryOp(x, token.QUO, d)
case exp > 0:
x = exact.Shift(x, token.SHL, uint(exp))
}
return x
}
func (p *importer) fraction() exact.Value {
sign := p.int()
if sign == 0 {
return exact.MakeInt64(0)
}
x := exact.BinaryOp(p.ufloat(), token.QUO, p.ufloat())
if sign < 0 {
x = exact.UnaryOp(token.SUB, x, 0)
}
return x
}
func (p *importer) value() exact.Value {
switch kind := exact.Kind(p.int()); kind {
case falseTag:
return exact.MakeBool(false)
case trueTag:
return exact.MakeBool(true)
case int64Tag:
return exact.MakeInt64(p.int64())
case floatTag:
return p.float()
case fractionTag:
return p.fraction()
case complexTag:
re := p.fraction()
im := p.fraction()
return exact.BinaryOp(re, token.ADD, exact.MakeImag(im))
case stringTag:
return exact.MakeString(p.string())
default:
panic(fmt.Sprintf("unexpected value kind %d", kind))
}
}
// intConst returns an untyped integer constant that evaluates to i.
func intConst(i int64) *Const {
return NewConst(exact.MakeInt64(i), types.Typ[types.UntypedInt])
}
func (c *funcContext) newInt(i int, t types.Type) *ast.BasicLit {
lit := &ast.BasicLit{Kind: token.INT}
c.p.info.Types[lit] = types.TypeAndValue{Type: t, Value: exact.MakeInt64(int64(i))}
return lit
}
// collectObjects collects all file and package objects and inserts them
// into their respective scopes. It also performs imports and associates
// methods with receiver base type names.
func (check *checker) collectObjects() {
pkg := check.pkg
importer := check.conf.Import
if importer == nil {
if DefaultImport == nil {
panic(`no Config.Import or DefaultImport (missing import _ "code.google.com/p/go.tools/go/gcimporter"?)`)
}
importer = DefaultImport
}
// pkgImports is the set of packages already imported by any package file seen
// so far. Used to avoid duplicate entries in pkg.imports. Allocate and populate
// it (pkg.imports may not be empty if we are checking test files incrementally).
var pkgImports = make(map[*Package]bool)
for _, imp := range pkg.imports {
pkgImports[imp] = true
}
for fileNo, file := range check.files {
// The package identifier denotes the current package,
// but there is no corresponding package object.
check.recordDef(file.Name, nil)
fileScope := check.fileScopes[fileNo]
for _, decl := range file.Decls {
switch d := decl.(type) {
case *ast.BadDecl:
// ignore
case *ast.GenDecl:
var last *ast.ValueSpec // last ValueSpec with type or init exprs seen
for iota, spec := range d.Specs {
switch s := spec.(type) {
case *ast.ImportSpec:
// import package
var imp *Package
path, err := validatedImportPath(s.Path.Value)
if err != nil {
check.errorf(s.Path.Pos(), "invalid import path (%s)", err)
continue
}
if path == "C" && check.conf.FakeImportC {
// TODO(gri) shouldn't create a new one each time
imp = NewPackage("C", "C")
imp.fake = true
} else {
var err error
imp, err = importer(check.conf.Packages, path)
if imp == nil && err == nil {
err = errors.New("Config.Import returned nil but no error")
}
if err != nil {
check.errorf(s.Path.Pos(), "could not import %s (%s)", path, err)
continue
}
}
// add package to list of explicit imports
// (this functionality is provided as a convenience
// for clients; it is not needed for type-checking)
if !pkgImports[imp] {
pkgImports[imp] = true
if imp != Unsafe {
pkg.imports = append(pkg.imports, imp)
}
}
// local name overrides imported package name
name := imp.name
if s.Name != nil {
name = s.Name.Name
if name == "init" {
check.errorf(s.Name.Pos(), "cannot declare init - must be func")
continue
}
}
obj := NewPkgName(s.Pos(), imp, name)
if s.Name != nil {
// in a dot-import, the dot represents the package
check.recordDef(s.Name, obj)
} else {
check.recordImplicit(s, obj)
}
// add import to file scope
if name == "." {
// merge imported scope with file scope
for _, obj := range imp.scope.elems {
// A package scope may contain non-exported objects,
// do not import them!
if obj.Exported() {
check.declare(fileScope, nil, obj)
check.recordImplicit(s, obj)
}
}
// add position to set of dot-import positions for this file
// (this is only needed for "imported but not used" errors)
posSet := check.dotImports[fileNo]
if posSet == nil {
posSet = make(map[*Package]token.Pos)
check.dotImports[fileNo] = posSet
}
posSet[imp] = s.Pos()
} else {
// declare imported package object in file scope
check.declare(fileScope, nil, obj)
}
case *ast.ValueSpec:
switch d.Tok {
case token.CONST:
// determine which initialization expressions to use
switch {
case s.Type != nil || len(s.Values) > 0:
last = s
case last == nil:
last = new(ast.ValueSpec) // make sure last exists
}
// declare all constants
for i, name := range s.Names {
obj := NewConst(name.Pos(), pkg, name.Name, nil, exact.MakeInt64(int64(iota)))
var init ast.Expr
if i < len(last.Values) {
init = last.Values[i]
}
d := &declInfo{file: fileScope, typ: last.Type, init: init}
check.declarePkgObj(name, obj, d)
}
check.arityMatch(s, last)
case token.VAR:
lhs := make([]*Var, len(s.Names))
// If there's exactly one rhs initializer, use
// the same declInfo d1 for all lhs variables
// so that each lhs variable depends on the same
// rhs initializer (n:1 var declaration).
var d1 *declInfo
if len(s.Values) == 1 {
// The lhs elements are only set up after the for loop below,
// but that's ok because declareVar only collects the declInfo
// for a later phase.
d1 = &declInfo{file: fileScope, lhs: lhs, typ: s.Type, init: s.Values[0]}
}
// declare all variables
for i, name := range s.Names {
obj := NewVar(name.Pos(), pkg, name.Name, nil)
lhs[i] = obj
d := d1
if d == nil {
// individual assignments
var init ast.Expr
if i < len(s.Values) {
init = s.Values[i]
}
d = &declInfo{file: fileScope, typ: s.Type, init: init}
}
check.declarePkgObj(name, obj, d)
}
check.arityMatch(s, nil)
default:
check.invalidAST(s.Pos(), "invalid token %s", d.Tok)
}
case *ast.TypeSpec:
obj := NewTypeName(s.Name.Pos(), pkg, s.Name.Name, nil)
check.declarePkgObj(s.Name, obj, &declInfo{file: fileScope, typ: s.Type})
default:
check.invalidAST(s.Pos(), "unknown ast.Spec node %T", s)
}
}
case *ast.FuncDecl:
name := d.Name.Name
obj := NewFunc(d.Name.Pos(), pkg, name, nil)
if d.Recv == nil {
// regular function
if name == "init" {
// don't declare init functions in the package scope - they are invisible
obj.parent = pkg.scope
check.recordDef(d.Name, obj)
// init functions must have a body
if d.Body == nil {
check.softErrorf(obj.pos, "missing function body")
}
} else {
check.declare(pkg.scope, d.Name, obj)
}
} else {
// method
check.recordDef(d.Name, obj)
// Associate method with receiver base type name, if possible.
// Ignore methods that have an invalid receiver, or a blank _
// receiver name. They will be type-checked later, with regular
// functions.
if list := d.Recv.List; len(list) > 0 {
typ := list[0].Type
if ptr, _ := typ.(*ast.StarExpr); ptr != nil {
typ = ptr.X
}
if base, _ := typ.(*ast.Ident); base != nil && base.Name != "_" {
check.assocMethod(base.Name, obj)
}
}
}
info := &declInfo{file: fileScope, fdecl: d}
check.objMap[obj] = info
default:
check.invalidAST(d.Pos(), "unknown ast.Decl node %T", d)
}
}
}
// verify that objects in package and file scopes have different names
for _, scope := range check.fileScopes {
for _, obj := range scope.elems {
if alt := pkg.scope.Lookup(obj.Name()); alt != nil {
check.errorf(alt.Pos(), "%s already declared in this file through import of package %s", obj.Name(), obj.Pkg().Name())
}
}
}
}
func (c *funcContext) translateStmt(stmt ast.Stmt, label string) {
c.Write([]byte{'\b'})
binary.Write(c, binary.BigEndian, uint32(stmt.Pos()))
switch s := stmt.(type) {
case *ast.BlockStmt:
c.translateStmtList(s.List)
case *ast.IfStmt:
c.printLabel(label)
if s.Init != nil {
c.translateStmt(s.Init, "")
}
var caseClauses []ast.Stmt
ifStmt := s
for {
caseClauses = append(caseClauses, &ast.CaseClause{List: []ast.Expr{ifStmt.Cond}, Body: ifStmt.Body.List})
switch elseStmt := ifStmt.Else.(type) {
case *ast.IfStmt:
if elseStmt.Init != nil {
caseClauses = append(caseClauses, &ast.CaseClause{List: nil, Body: []ast.Stmt{elseStmt}})
break
}
ifStmt = elseStmt
continue
case *ast.BlockStmt:
caseClauses = append(caseClauses, &ast.CaseClause{List: nil, Body: elseStmt.List})
case *ast.EmptyStmt, nil:
// no else clause
default:
panic(fmt.Sprintf("Unhandled else: %T\n", elseStmt))
}
break
}
c.translateBranchingStmt(caseClauses, false, c.translateExpr, nil, "", c.hasGoto[s])
case *ast.SwitchStmt:
if s.Init != nil {
c.translateStmt(s.Init, "")
}
translateCond := func(cond ast.Expr) *expression {
return c.translateExpr(cond)
}
if s.Tag != nil {
refVar := c.newVariable("_ref")
c.Printf("%s = %s;", refVar, c.translateExpr(s.Tag))
translateCond = func(cond ast.Expr) *expression {
refIdent := c.newIdent(refVar, c.p.info.Types[s.Tag].Type)
return c.translateExpr(&ast.BinaryExpr{
X: refIdent,
Op: token.EQL,
Y: cond,
})
}
}
c.translateBranchingStmt(s.Body.List, true, translateCond, nil, label, c.hasGoto[s])
case *ast.TypeSwitchStmt:
if s.Init != nil {
c.translateStmt(s.Init, "")
}
var expr ast.Expr
var typeSwitchVar string
switch a := s.Assign.(type) {
case *ast.AssignStmt:
expr = a.Rhs[0].(*ast.TypeAssertExpr).X
typeSwitchVar = c.newVariable(a.Lhs[0].(*ast.Ident).Name)
for _, caseClause := range s.Body.List {
c.p.objectVars[c.p.info.Implicits[caseClause]] = typeSwitchVar
}
case *ast.ExprStmt:
expr = a.X.(*ast.TypeAssertExpr).X
}
refVar := c.newVariable("_ref")
typeVar := c.newVariable("_type")
c.Printf("%s = %s;", refVar, c.translateExpr(expr))
c.Printf("%s = %s !== null ? %s.constructor : null;", typeVar, refVar, refVar)
translateCond := func(cond ast.Expr) *expression {
return c.formatExpr("%s", c.typeCheck(typeVar, c.p.info.Types[cond].Type))
}
printCaseBodyPrefix := func(conds []ast.Expr) {
if typeSwitchVar == "" {
return
}
value := refVar
if len(conds) == 1 {
t := c.p.info.Types[conds[0]].Type
if _, isInterface := t.Underlying().(*types.Interface); !isInterface && !types.Identical(t, types.Typ[types.UntypedNil]) {
value += ".go$val"
}
}
c.Printf("%s = %s;", typeSwitchVar, value)
}
c.translateBranchingStmt(s.Body.List, true, translateCond, printCaseBodyPrefix, label, c.hasGoto[s])
case *ast.ForStmt:
if s.Init != nil {
c.translateStmt(s.Init, "")
}
cond := "true"
if s.Cond != nil {
cond = c.translateExpr(s.Cond).String()
}
c.translateLoopingStmt(cond, s.Body, nil, func() {
if s.Post != nil {
c.translateStmt(s.Post, "")
}
}, label, c.hasGoto[s])
case *ast.RangeStmt:
refVar := c.newVariable("_ref")
c.Printf("%s = %s;", refVar, c.translateExpr(s.X))
iVar := c.newVariable("_i")
c.Printf("%s = 0;", iVar)
switch t := c.p.info.Types[s.X].Type.Underlying().(type) {
case *types.Basic:
runeVar := c.newVariable("_rune")
c.translateLoopingStmt(iVar+" < "+refVar+".length", s.Body, func() {
c.Printf("%s = go$decodeRune(%s, %s);", runeVar, refVar, iVar)
if !isBlank(s.Value) {
c.Printf("%s", c.translateAssign(s.Value, runeVar+"[0]"))
}
if !isBlank(s.Key) {
c.Printf("%s", c.translateAssign(s.Key, iVar))
}
}, func() {
c.Printf("%s += %s[1];", iVar, runeVar)
}, label, c.hasGoto[s])
case *types.Map:
keysVar := c.newVariable("_keys")
c.Printf("%s = go$keys(%s);", keysVar, refVar)
c.translateLoopingStmt(iVar+" < "+keysVar+".length", s.Body, func() {
entryVar := c.newVariable("_entry")
c.Printf("%s = %s[%s[%s]];", entryVar, refVar, keysVar, iVar)
if !isBlank(s.Value) {
c.Printf("%s", c.translateAssign(s.Value, entryVar+".v"))
}
if !isBlank(s.Key) {
c.Printf("%s", c.translateAssign(s.Key, entryVar+".k"))
}
}, func() {
c.Printf("%s++;", iVar)
}, label, c.hasGoto[s])
case *types.Array, *types.Pointer, *types.Slice:
var length string
switch t2 := t.(type) {
case *types.Array:
length = fmt.Sprintf("%d", t2.Len())
case *types.Pointer:
length = fmt.Sprintf("%d", t2.Elem().Underlying().(*types.Array).Len())
case *types.Slice:
length = refVar + ".length"
}
c.translateLoopingStmt(iVar+" < "+length, s.Body, func() {
if !isBlank(s.Value) {
indexExpr := &ast.IndexExpr{
X: c.newIdent(refVar, t),
Index: c.newIdent(iVar, types.Typ[types.Int]),
}
et := elemType(t)
c.p.info.Types[indexExpr] = types.TypeAndValue{Type: et}
c.Printf("%s", c.translateAssign(s.Value, c.translateImplicitConversion(indexExpr, et).String()))
}
if !isBlank(s.Key) {
c.Printf("%s", c.translateAssign(s.Key, iVar))
}
}, func() {
c.Printf("%s++;", iVar)
}, label, c.hasGoto[s])
case *types.Chan:
c.printLabel(label)
// skip
default:
panic("")
}
case *ast.BranchStmt:
c.printLabel(label)
labelSuffix := ""
data := c.flowDatas[""]
if s.Label != nil {
labelSuffix = " " + s.Label.Name
data = c.flowDatas[s.Label.Name]
}
switch s.Tok {
case token.BREAK:
c.PrintCond(data.endCase == 0, fmt.Sprintf("break%s;", labelSuffix), fmt.Sprintf("go$s = %d; continue;", data.endCase))
case token.CONTINUE:
data.postStmt()
c.PrintCond(data.beginCase == 0, fmt.Sprintf("continue%s;", labelSuffix), fmt.Sprintf("go$s = %d; continue;", data.beginCase))
case token.GOTO:
c.PrintCond(false, "goto "+s.Label.Name, fmt.Sprintf("go$s = %d; continue;", c.labelCases[s.Label.Name]))
case token.FALLTHROUGH:
// handled in CaseClause
default:
panic("Unhandled branch statment: " + s.Tok.String())
}
case *ast.ReturnStmt:
c.printLabel(label)
results := s.Results
if c.resultNames != nil {
if len(s.Results) != 0 {
c.translateStmt(&ast.AssignStmt{
Lhs: c.resultNames,
Tok: token.ASSIGN,
Rhs: s.Results,
}, "")
}
results = c.resultNames
}
switch len(results) {
case 0:
c.Printf("return;")
case 1:
if c.sig.Results().Len() > 1 {
c.Printf("return %s;", c.translateExpr(results[0]))
break
}
v := c.translateImplicitConversion(results[0], c.sig.Results().At(0).Type())
c.delayedOutput = nil
c.Printf("return %s;", v)
default:
values := make([]string, len(results))
for i, result := range results {
values[i] = c.translateImplicitConversion(result, c.sig.Results().At(i).Type()).String()
}
c.delayedOutput = nil
c.Printf("return [%s];", strings.Join(values, ", "))
}
case *ast.DeferStmt:
c.printLabel(label)
if ident, isIdent := s.Call.Fun.(*ast.Ident); isIdent {
if builtin, isBuiltin := c.p.info.Uses[ident].(*types.Builtin); isBuiltin {
if builtin.Name() == "recover" {
c.Printf("go$deferred.push({ fun: go$recover, args: [] });")
return
}
args := make([]ast.Expr, len(s.Call.Args))
for i, arg := range s.Call.Args {
args[i] = c.newIdent(c.newVariable("_arg"), c.p.info.Types[arg].Type)
}
call := c.translateExpr(&ast.CallExpr{
Fun: s.Call.Fun,
Args: args,
Ellipsis: s.Call.Ellipsis,
})
c.Printf("go$deferred.push({ fun: function(%s) { %s; }, args: [%s] });", strings.Join(c.translateExprSlice(args, nil), ", "), call, strings.Join(c.translateExprSlice(s.Call.Args, nil), ", "))
return
}
}
sig := c.p.info.Types[s.Call.Fun].Type.Underlying().(*types.Signature)
args := strings.Join(c.translateArgs(sig, s.Call.Args, s.Call.Ellipsis.IsValid()), ", ")
if sel, isSelector := s.Call.Fun.(*ast.SelectorExpr); isSelector {
obj := c.p.info.Selections[sel].Obj()
if !obj.Exported() {
c.p.dependencies[obj] = true
}
c.Printf(`go$deferred.push({ recv: %s, method: "%s", args: [%s] });`, c.translateExpr(sel.X), sel.Sel.Name, args)
return
}
c.Printf("go$deferred.push({ fun: %s, args: [%s] });", c.translateExpr(s.Call.Fun), args)
case *ast.AssignStmt:
c.printLabel(label)
if s.Tok != token.ASSIGN && s.Tok != token.DEFINE {
var op token.Token
switch s.Tok {
case token.ADD_ASSIGN:
op = token.ADD
case token.SUB_ASSIGN:
op = token.SUB
case token.MUL_ASSIGN:
op = token.MUL
case token.QUO_ASSIGN:
op = token.QUO
case token.REM_ASSIGN:
op = token.REM
case token.AND_ASSIGN:
op = token.AND
case token.OR_ASSIGN:
op = token.OR
case token.XOR_ASSIGN:
op = token.XOR
case token.SHL_ASSIGN:
op = token.SHL
case token.SHR_ASSIGN:
op = token.SHR
case token.AND_NOT_ASSIGN:
op = token.AND_NOT
default:
panic(s.Tok)
}
var parts []string
lhs := s.Lhs[0]
switch l := lhs.(type) {
case *ast.IndexExpr:
lhsVar := c.newVariable("_lhs")
indexVar := c.newVariable("_index")
parts = append(parts, lhsVar+" = "+c.translateExpr(l.X).String()+";")
parts = append(parts, indexVar+" = "+c.translateExpr(l.Index).String()+";")
lhs = &ast.IndexExpr{
X: c.newIdent(lhsVar, c.p.info.Types[l.X].Type),
Index: c.newIdent(indexVar, c.p.info.Types[l.Index].Type),
}
c.p.info.Types[lhs] = c.p.info.Types[l]
case *ast.StarExpr:
lhsVar := c.newVariable("_lhs")
parts = append(parts, lhsVar+" = "+c.translateExpr(l.X).String()+";")
lhs = &ast.StarExpr{
X: c.newIdent(lhsVar, c.p.info.Types[l.X].Type),
}
c.p.info.Types[lhs] = c.p.info.Types[l]
case *ast.SelectorExpr:
v := hasCallVisitor{c.p.info, false}
ast.Walk(&v, l.X)
if v.hasCall {
lhsVar := c.newVariable("_lhs")
parts = append(parts, lhsVar+" = "+c.translateExpr(l.X).String()+";")
lhs = &ast.SelectorExpr{
X: c.newIdent(lhsVar, c.p.info.Types[l.X].Type),
Sel: l.Sel,
}
c.p.info.Types[lhs] = c.p.info.Types[l]
c.p.info.Selections[lhs.(*ast.SelectorExpr)] = c.p.info.Selections[l]
}
}
parenExpr := &ast.ParenExpr{X: s.Rhs[0]}
c.p.info.Types[parenExpr] = c.p.info.Types[s.Rhs[0]]
binaryExpr := &ast.BinaryExpr{
X: lhs,
Op: op,
Y: parenExpr,
}
c.p.info.Types[binaryExpr] = c.p.info.Types[s.Lhs[0]]
parts = append(parts, c.translateAssign(lhs, c.translateExpr(binaryExpr).String()))
c.Printf("%s", strings.Join(parts, " "))
return
}
if s.Tok == token.DEFINE {
for _, lhs := range s.Lhs {
if !isBlank(lhs) {
c.p.info.Types[lhs] = types.TypeAndValue{Type: c.p.info.Defs[lhs.(*ast.Ident)].Type()}
}
}
}
removeParens := func(e ast.Expr) ast.Expr {
for {
if p, isParen := e.(*ast.ParenExpr); isParen {
e = p.X
continue
}
break
}
return e
}
switch {
case len(s.Lhs) == 1 && len(s.Rhs) == 1:
lhs := removeParens(s.Lhs[0])
if isBlank(lhs) {
v := hasCallVisitor{c.p.info, false}
ast.Walk(&v, s.Rhs[0])
if v.hasCall {
c.Printf("%s;", c.translateExpr(s.Rhs[0]).String())
}
return
}
c.Printf("%s", c.translateAssign(lhs, c.translateImplicitConversion(s.Rhs[0], c.p.info.Types[s.Lhs[0]].Type).String()))
case len(s.Lhs) > 1 && len(s.Rhs) == 1:
tupleVar := c.newVariable("_tuple")
out := tupleVar + " = " + c.translateExpr(s.Rhs[0]).String() + ";"
tuple := c.p.info.Types[s.Rhs[0]].Type.(*types.Tuple)
for i, lhs := range s.Lhs {
lhs = removeParens(lhs)
if !isBlank(lhs) {
out += " " + c.translateAssign(lhs, c.translateImplicitConversion(c.newIdent(fmt.Sprintf("%s[%d]", tupleVar, i), tuple.At(i).Type()), c.p.info.Types[s.Lhs[i]].Type).String())
}
}
c.Printf("%s", out)
case len(s.Lhs) == len(s.Rhs):
parts := make([]string, len(s.Rhs))
for i, rhs := range s.Rhs {
parts[i] = c.translateImplicitConversion(rhs, c.p.info.Types[s.Lhs[i]].Type).String()
}
tupleVar := c.newVariable("_tuple")
out := tupleVar + " = [" + strings.Join(parts, ", ") + "];"
for i, lhs := range s.Lhs {
lhs = removeParens(lhs)
if !isBlank(lhs) {
out += " " + c.translateAssign(lhs, fmt.Sprintf("%s[%d]", tupleVar, i))
}
}
c.Printf("%s", out)
default:
panic("Invalid arity of AssignStmt.")
}
case *ast.IncDecStmt:
t := c.p.info.Types[s.X].Type
if iExpr, isIExpr := s.X.(*ast.IndexExpr); isIExpr {
switch u := c.p.info.Types[iExpr.X].Type.Underlying().(type) {
case *types.Array:
t = u.Elem()
case *types.Slice:
t = u.Elem()
case *types.Map:
t = u.Elem()
}
}
tok := token.ADD_ASSIGN
if s.Tok == token.DEC {
tok = token.SUB_ASSIGN
}
one := &ast.BasicLit{
Kind: token.INT,
Value: "1",
}
c.p.info.Types[one] = types.TypeAndValue{Type: t, Value: exact.MakeInt64(1)}
c.translateStmt(&ast.AssignStmt{
Lhs: []ast.Expr{s.X},
Tok: tok,
Rhs: []ast.Expr{one},
}, label)
case *ast.ExprStmt:
c.printLabel(label)
c.Printf("%s;", c.translateExpr(s.X).String())
case *ast.DeclStmt:
c.printLabel(label)
decl := s.Decl.(*ast.GenDecl)
switch decl.Tok {
case token.VAR:
for _, spec := range s.Decl.(*ast.GenDecl).Specs {
valueSpec := spec.(*ast.ValueSpec)
lhs := make([]ast.Expr, len(valueSpec.Names))
for i, name := range valueSpec.Names {
lhs[i] = name
}
rhs := valueSpec.Values
isTuple := false
if len(rhs) == 1 {
_, isTuple = c.p.info.Types[rhs[0]].Type.(*types.Tuple)
}
for len(rhs) < len(lhs) && !isTuple {
rhs = append(rhs, nil)
}
c.translateStmt(&ast.AssignStmt{
Lhs: lhs,
Tok: token.DEFINE,
Rhs: rhs,
}, "")
}
case token.TYPE:
for _, spec := range decl.Specs {
o := c.p.info.Defs[spec.(*ast.TypeSpec).Name].(*types.TypeName)
c.translateType(o, false)
c.initType(o)
}
case token.CONST:
// skip, constants are inlined
}
case *ast.LabeledStmt:
c.printLabel(label)
c.translateStmt(s.Stmt, s.Label.Name)
case *ast.SelectStmt:
c.printLabel(label)
c.Printf(`go$notSupported("select");`)
case *ast.GoStmt:
c.printLabel(label)
c.Printf(`go$notSupported("go");`)
case *ast.SendStmt:
c.printLabel(label)
c.Printf(`go$notSupported("send");`)
case *ast.EmptyStmt:
// skip
default:
panic(fmt.Sprintf("Unhandled statement: %T\n", s))
}
}
// builtin typechecks a call to a built-in and returns the result via x.
// If the call has type errors, the returned x is marked as invalid.
//
func (check *checker) builtin(x *operand, call *ast.CallExpr, id builtinId) {
args := call.Args
// declare before goto's
var arg0 ast.Expr // first argument, if present
// check argument count
n := len(args)
msg := ""
bin := predeclaredFuncs[id]
if n < bin.nargs {
msg = "not enough"
} else if !bin.variadic && n > bin.nargs {
msg = "too many"
}
if msg != "" {
check.invalidOp(call.Pos(), msg+" arguments for %s (expected %d, found %d)", call, bin.nargs, n)
goto Error
}
// common case: evaluate first argument if present;
// if it is an expression, x has the expression value
if n > 0 {
arg0 = args[0]
switch id {
case _Make, _New, _Print, _Println, _Offsetof, _Trace:
// respective cases below do the work
default:
// argument must be an expression
check.expr(x, arg0)
if x.mode == invalid {
goto Error
}
}
}
switch id {
case _Append:
if _, ok := x.typ.Underlying().(*Slice); !ok {
check.invalidArg(x.pos(), "%s is not a typed slice", x)
goto Error
}
resultTyp := x.typ
for _, arg := range args[1:] {
check.expr(x, arg)
if x.mode == invalid {
goto Error
}
// TODO(gri) check assignability
}
x.mode = value
x.typ = resultTyp
case _Cap, _Len:
mode := invalid
var val exact.Value
switch typ := implicitArrayDeref(x.typ.Underlying()).(type) {
case *Basic:
if isString(typ) && id == _Len {
if x.mode == constant {
mode = constant
val = exact.MakeInt64(int64(len(exact.StringVal(x.val))))
} else {
mode = value
}
}
case *Array:
mode = value
// spec: "The expressions len(s) and cap(s) are constants
// if the type of s is an array or pointer to an array and
// the expression s does not contain channel receives or
// function calls; in this case s is not evaluated."
if !check.containsCallsOrReceives(arg0) {
mode = constant
val = exact.MakeInt64(typ.len)
}
case *Slice, *Chan:
mode = value
case *Map:
if id == _Len {
mode = value
}
}
if mode == invalid {
check.invalidArg(x.pos(), "%s for %s", x, bin.name)
goto Error
}
x.mode = mode
x.typ = Typ[Int]
x.val = val
case _Close:
ch, ok := x.typ.Underlying().(*Chan)
if !ok {
check.invalidArg(x.pos(), "%s is not a channel", x)
goto Error
}
if ch.dir&ast.SEND == 0 {
check.invalidArg(x.pos(), "%s must not be a receive-only channel", x)
goto Error
}
x.mode = novalue
case _Complex:
if !check.complexArg(x) {
goto Error
}
var y operand
check.expr(&y, args[1])
if y.mode == invalid {
goto Error
}
if !check.complexArg(&y) {
goto Error
}
check.convertUntyped(x, y.typ)
if x.mode == invalid {
goto Error
}
check.convertUntyped(&y, x.typ)
if y.mode == invalid {
goto Error
}
if !IsIdentical(x.typ, y.typ) {
check.invalidArg(x.pos(), "mismatched types %s and %s", x.typ, y.typ)
goto Error
}
typ := x.typ.Underlying().(*Basic)
if x.mode == constant && y.mode == constant {
x.val = exact.BinaryOp(x.val, token.ADD, exact.MakeImag(y.val))
} else {
x.mode = value
}
switch typ.kind {
case Float32:
x.typ = Typ[Complex64]
case Float64:
x.typ = Typ[Complex128]
case UntypedInt, UntypedRune, UntypedFloat:
if x.mode == constant {
typ = defaultType(typ).(*Basic)
x.typ = Typ[UntypedComplex]
} else {
// untyped but not constant; probably because one
// operand is a non-constant shift of untyped lhs
typ = Typ[Float64]
x.typ = Typ[Complex128]
}
default:
check.invalidArg(x.pos(), "float32 or float64 arguments expected")
goto Error
}
if x.mode != constant {
// The arguments have now their final types, which at run-
// time will be materialized. Update the expression trees.
// If the current types are untyped, the materialized type
// is the respective default type.
// (If the result is constant, the arguments are never
// materialized and there is nothing to do.)
check.updateExprType(args[0], typ, true)
check.updateExprType(args[1], typ, true)
}
case _Copy:
var y operand
check.expr(&y, args[1])
if y.mode == invalid {
goto Error
}
var dst, src Type
if t, ok := x.typ.Underlying().(*Slice); ok {
dst = t.elt
}
switch t := y.typ.Underlying().(type) {
case *Basic:
if isString(y.typ) {
src = Typ[Byte]
}
case *Slice:
src = t.elt
}
if dst == nil || src == nil {
check.invalidArg(x.pos(), "copy expects slice arguments; found %s and %s", x, &y)
goto Error
}
if !IsIdentical(dst, src) {
check.invalidArg(x.pos(), "arguments to copy %s and %s have different element types %s and %s", x, &y, dst, src)
goto Error
}
x.mode = value
x.typ = Typ[Int]
case _Delete:
m, ok := x.typ.Underlying().(*Map)
if !ok {
check.invalidArg(x.pos(), "%s is not a map", x)
goto Error
}
check.expr(x, args[1])
if x.mode == invalid {
goto Error
}
if !x.isAssignableTo(check.conf, m.key) {
check.invalidArg(x.pos(), "%s is not assignable to %s", x, m.key)
goto Error
}
x.mode = novalue
case _Imag, _Real:
if !isComplex(x.typ) {
check.invalidArg(x.pos(), "%s must be a complex number", x)
goto Error
}
if x.mode == constant {
if id == _Real {
x.val = exact.Real(x.val)
} else {
x.val = exact.Imag(x.val)
}
} else {
x.mode = value
}
k := Invalid
switch x.typ.Underlying().(*Basic).kind {
case Complex64:
k = Float32
case Complex128:
k = Float64
case UntypedComplex:
k = UntypedFloat
default:
unreachable()
}
x.typ = Typ[k]
case _Make:
resultTyp := check.typ(arg0, nil, false)
if resultTyp == Typ[Invalid] {
goto Error
}
var min int // minimum number of arguments
switch resultTyp.Underlying().(type) {
case *Slice:
min = 2
case *Map, *Chan:
min = 1
default:
check.invalidArg(arg0.Pos(), "cannot make %s; type must be slice, map, or channel", arg0)
goto Error
}
if n := len(args); n < min || min+1 < n {
check.errorf(call.Pos(), "%s expects %d or %d arguments; found %d", call, min, min+1, n)
goto Error
}
var sizes []int64 // constant integer arguments, if any
for _, arg := range args[1:] {
if s, ok := check.index(arg, -1); ok && s >= 0 {
sizes = append(sizes, s)
}
}
if len(sizes) == 2 && sizes[0] > sizes[1] {
check.invalidArg(args[1].Pos(), "length and capacity swapped")
// safe to continue
}
x.mode = variable
x.typ = resultTyp
case _New:
resultTyp := check.typ(arg0, nil, false)
if resultTyp == Typ[Invalid] {
goto Error
}
x.mode = variable
x.typ = &Pointer{base: resultTyp}
case _Panic:
x.mode = novalue
case _Print, _Println:
for _, arg := range args {
check.expr(x, arg)
if x.mode == invalid {
goto Error
}
}
x.mode = novalue
case _Recover:
x.mode = value
x.typ = new(Interface)
case _Alignof:
x.mode = constant
x.val = exact.MakeInt64(check.conf.alignof(x.typ))
x.typ = Typ[Uintptr]
case _Offsetof:
arg, ok := unparen(arg0).(*ast.SelectorExpr)
if !ok {
check.invalidArg(arg0.Pos(), "%s is not a selector expression", arg0)
goto Error
}
check.expr(x, arg.X)
if x.mode == invalid {
goto Error
}
base := derefStructPtr(x.typ)
sel := arg.Sel.Name
obj, index, indirect := LookupFieldOrMethod(base, check.pkg, arg.Sel.Name)
switch obj.(type) {
case nil:
check.invalidArg(x.pos(), "%s has no single field %s", base, sel)
goto Error
case *Func:
check.invalidArg(arg0.Pos(), "%s is a method value", arg0)
goto Error
}
if indirect {
check.invalidArg(x.pos(), "field %s is embedded via a pointer in %s", sel, base)
goto Error
}
// TODO(gri) Should we pass x.typ instead of base (and indirect report if derefStructPtr indirected)?
check.recordSelection(arg, FieldVal, base, obj, index, false)
offs := check.conf.offsetof(base, index)
x.mode = constant
x.val = exact.MakeInt64(offs)
x.typ = Typ[Uintptr]
case _Sizeof:
x.mode = constant
x.val = exact.MakeInt64(check.conf.sizeof(x.typ))
x.typ = Typ[Uintptr]
case _Assert:
// assert(pred) causes a typechecker error if pred is false.
// The result of assert is the value of pred if there is no error.
// Note: assert is only available in self-test mode.
if x.mode != constant || !isBoolean(x.typ) {
check.invalidArg(x.pos(), "%s is not a boolean constant", x)
goto Error
}
if x.val.Kind() != exact.Bool {
check.errorf(x.pos(), "internal error: value of %s should be a boolean constant", x)
goto Error
}
if !exact.BoolVal(x.val) {
check.errorf(call.Pos(), "%s failed", call)
// compile-time assertion failure - safe to continue
}
case _Trace:
// trace(x, y, z, ...) dumps the positions, expressions, and
// values of its arguments. The result of trace is the value
// of the first argument.
// Note: trace is only available in self-test mode.
if len(args) == 0 {
check.dump("%s: trace() without arguments", call.Pos())
x.mode = novalue
x.expr = call
return
}
var t operand
x1 := x
for _, arg := range args {
check.rawExpr(x1, arg, nil) // permit trace for types, e.g.: new(trace(T))
check.dump("%s: %s", x1.pos(), x1)
x1 = &t // use incoming x only for first argument
}
default:
unreachable()
}
x.expr = call
return
Error:
x.mode = invalid
x.expr = call
}
func (check *checker) resolveFiles(files []*ast.File) {
pkg := check.pkg
// Phase 1: Pre-declare all package-level objects so that they can be found
// independent of source order. Associate methods with receiver
// base type names.
var (
fileScope *Scope // current file scope
objList []Object // list of package-level objects to type-check
objMap = make(map[Object]declInfo) // declaration info for each package-level object
)
// declare declares obj in the package scope, records its ident -> obj mapping,
// and updates objList and objMap. The object must not be a function or method.
declare := func(ident *ast.Ident, obj Object, typ, init ast.Expr) {
assert(ident.Name == obj.Name())
// spec: "A package-scope or file-scope identifier with name init
// may only be declared to be a function with this (func()) signature."
if ident.Name == "init" {
check.errorf(ident.Pos(), "cannot declare init - must be func")
return
}
check.declareObj(pkg.scope, ident, obj)
objList = append(objList, obj)
objMap[obj] = declInfo{fileScope, typ, init, nil}
}
importer := check.conf.Import
if importer == nil {
importer = GcImport
}
var (
seenPkgs = make(map[*Package]bool) // imported packages that have been seen already
fileScopes []*Scope // file scope for each file
dotImports []map[*Package]token.Pos // positions of dot-imports for each file
)
for _, file := range files {
// The package identifier denotes the current package,
// but there is no corresponding package object.
check.recordObject(file.Name, nil)
fileScope = NewScope(pkg.scope)
check.recordScope(file, fileScope)
fileScopes = append(fileScopes, fileScope)
dotImports = append(dotImports, nil) // element (map) is lazily allocated
for _, decl := range file.Decls {
switch d := decl.(type) {
case *ast.BadDecl:
// ignore
case *ast.GenDecl:
var last *ast.ValueSpec // last ValueSpec with type or init exprs seen
for iota, spec := range d.Specs {
switch s := spec.(type) {
case *ast.ImportSpec:
// import package
var imp *Package
path, _ := strconv.Unquote(s.Path.Value)
if path == "C" && check.conf.FakeImportC {
// TODO(gri) shouldn't create a new one each time
imp = NewPackage("C", "C", NewScope(nil))
imp.fake = true
} else {
var err error
imp, err = importer(check.conf.Packages, path)
if imp == nil && err == nil {
err = errors.New("Config.Import returned nil but no error")
}
if err != nil {
check.errorf(s.Path.Pos(), "could not import %s (%s)", path, err)
continue
}
}
// add package to list of explicit imports
// (this functionality is provided as a convenience
// for clients; it is not needed for type-checking)
if !seenPkgs[imp] {
seenPkgs[imp] = true
if imp != Unsafe {
pkg.imports = append(pkg.imports, imp)
}
}
// local name overrides imported package name
name := imp.name
if s.Name != nil {
name = s.Name.Name
if name == "init" {
check.errorf(s.Name.Pos(), "cannot declare init - must be func")
continue
}
}
obj := NewPkgName(s.Pos(), imp, name)
if s.Name != nil {
// in a dot-import, the dot represents the package
check.recordObject(s.Name, obj)
} else {
check.recordImplicit(s, obj)
}
// add import to file scope
if name == "." {
// merge imported scope with file scope
for _, obj := range imp.scope.elems {
// A package scope may contain non-exported objects,
// do not import them!
if obj.IsExported() {
// Note: This will change each imported object's scope!
// May be an issue for type aliases.
check.declareObj(fileScope, nil, obj)
check.recordImplicit(s, obj)
}
}
// add position to set of dot-import positions for this file
// (this is only needed for "imported but not used" errors)
posSet := dotImports[len(dotImports)-1]
if posSet == nil {
posSet = make(map[*Package]token.Pos)
dotImports[len(dotImports)-1] = posSet
}
posSet[imp] = s.Pos()
} else {
// declare imported package object in file scope
check.declareObj(fileScope, nil, obj)
}
case *ast.ValueSpec:
switch d.Tok {
case token.CONST:
// determine which initialization expressions to use
switch {
case s.Type != nil || len(s.Values) > 0:
last = s
case last == nil:
last = new(ast.ValueSpec) // make sure last exists
}
// declare all constants
for i, name := range s.Names {
obj := NewConst(name.Pos(), pkg, name.Name, nil, exact.MakeInt64(int64(iota)))
var init ast.Expr
if i < len(last.Values) {
init = last.Values[i]
}
declare(name, obj, last.Type, init)
}
check.arityMatch(s, last)
case token.VAR:
// declare all variables
lhs := make([]*Var, len(s.Names))
for i, name := range s.Names {
obj := NewVar(name.Pos(), pkg, name.Name, nil)
lhs[i] = obj
var init ast.Expr
switch len(s.Values) {
case len(s.Names):
// lhs and rhs match
init = s.Values[i]
case 1:
// rhs must be a multi-valued expression
// (lhs may not be fully set up yet, but
// that's fine because declare simply collects
// the information for later processing.)
init = &multiExpr{lhs, s.Values, nil}
default:
if i < len(s.Values) {
init = s.Values[i]
}
}
declare(name, obj, s.Type, init)
}
check.arityMatch(s, nil)
default:
check.invalidAST(s.Pos(), "invalid token %s", d.Tok)
}
case *ast.TypeSpec:
obj := NewTypeName(s.Name.Pos(), pkg, s.Name.Name, nil)
declare(s.Name, obj, s.Type, nil)
default:
check.invalidAST(s.Pos(), "unknown ast.Spec node %T", s)
}
}
case *ast.FuncDecl:
name := d.Name.Name
obj := NewFunc(d.Name.Pos(), pkg, name, nil)
if d.Recv == nil {
// regular function
if name == "init" {
// don't declare init functions in the package scope - they are invisible
obj.parent = pkg.scope
check.recordObject(d.Name, obj)
// init functions must have a body
if d.Body == nil {
check.errorf(obj.pos, "missing function body")
// ok to continue
}
} else {
check.declareObj(pkg.scope, d.Name, obj)
}
} else {
// Associate method with receiver base type name, if possible.
// Ignore methods that have an invalid receiver, or a blank _
// receiver name. They will be type-checked later, with regular
// functions.
if list := d.Recv.List; len(list) > 0 {
typ := list[0].Type
if ptr, _ := typ.(*ast.StarExpr); ptr != nil {
typ = ptr.X
}
if base, _ := typ.(*ast.Ident); base != nil && base.Name != "_" {
check.methods[base.Name] = append(check.methods[base.Name], obj)
}
}
}
objList = append(objList, obj)
objMap[obj] = declInfo{fileScope, nil, nil, d}
default:
check.invalidAST(d.Pos(), "unknown ast.Decl node %T", d)
}
}
}
// Phase 2: Verify that objects in package and file scopes have different names.
for _, scope := range fileScopes {
for _, obj := range scope.elems {
if alt := pkg.scope.Lookup(obj.Name()); alt != nil {
check.errorf(alt.Pos(), "%s already declared in this file through import of package %s", obj.Name(), obj.Pkg().Name())
}
}
}
// Phase 3: Typecheck all objects in objList, but not function bodies.
check.objMap = objMap // indicate that we are checking global declarations (objects may not have a type yet)
for _, obj := range objList {
if obj.Type() == nil {
check.objDecl(obj, nil, false)
}
}
// done with package-level declarations
check.objMap = nil
objList = nil
// At this point we may have a non-empty check.methods map; this means that not all
// entries were deleted at the end of typeDecl because the respective receiver base
// types were not declared. In that case, an error was reported when declaring those
// methods. We can now safely discard this map.
check.methods = nil
// Phase 4: Typecheck all functions bodies.
// Note: funcList may grow while iterating through it - cannot use range clause.
for i := 0; i < len(check.funcList); i++ {
f := check.funcList[i]
if trace {
s := "<function literal>"
if f.obj != nil {
s = f.obj.name
}
fmt.Println("---", s)
}
check.topScope = f.sig.scope // open function scope
check.funcSig = f.sig
check.labels = nil // lazily allocated
check.stmtList(f.body.List, false)
if f.sig.results.Len() > 0 && !check.isTerminating(f.body, "") {
check.errorf(f.body.Rbrace, "missing return")
}
// spec: "It is illegal to define a label that is never used."
if check.labels != nil {
for _, obj := range check.labels.elems {
if l := obj.(*Label); !l.used {
check.errorf(l.pos, "%s defined but not used", l.name)
}
}
}
}
// Phase 5: Check for declared but not used packages and variables.
// Note: must happen after checking all functions because closures may affect outer scopes
// spec: "It is illegal (...) to directly import a package without referring to
// any of its exported identifiers. To import a package solely for its side-effects
// (initialization), use the blank identifier as explicit package name."
for i, scope := range fileScopes {
var usedDotImports map[*Package]bool // lazily allocated
for _, obj := range scope.elems {
switch obj := obj.(type) {
case *PkgName:
// Unused "blank imports" are automatically ignored
// since _ identifiers are not entered into scopes.
if !obj.used {
check.errorf(obj.pos, "%q imported but not used", obj.pkg.path)
}
default:
// All other objects in the file scope must be dot-
// imported. If an object was used, mark its package
// as used.
if obj.isUsed() {
if usedDotImports == nil {
usedDotImports = make(map[*Package]bool)
}
usedDotImports[obj.Pkg()] = true
}
}
}
// Iterate through all dot-imports for this file and
// check if the corresponding package was used.
for pkg, pos := range dotImports[i] {
if !usedDotImports[pkg] {
check.errorf(pos, "%q imported but not used", pkg.path)
}
}
}
// Each set of implicitly declared lhs variables in a type switch acts collectively
// as a single lhs variable. If any one was 'used', all of them are 'used'. Handle
// them before the general analysis.
for _, vars := range check.lhsVarsList {
// len(vars) > 0
var used bool
for _, v := range vars {
if v.used {
used = true
}
v.used = true // avoid later error
}
if !used {
v := vars[0]
check.errorf(v.pos, "%s declared but not used", v.name)
}
}
// spec: "Implementation restriction: A compiler may make it illegal to
// declare a variable inside a function body if the variable is never used."
for _, f := range check.funcList {
check.usage(f.sig.scope)
}
}
// ConstDecl = "const" ExportedName [ Type ] "=" Literal .
// Literal = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit .
// bool_lit = "true" | "false" .
// complex_lit = "(" float_lit "+" float_lit "i" ")" .
// rune_lit = "(" int_lit "+" int_lit ")" .
// string_lit = `"` { unicode_char } `"` .
//
func (p *gcParser) parseConstDecl() {
p.expectKeyword("const")
pkg, name := p.parseExportedName()
obj := declConst(pkg, name)
var x operand
if p.tok != '=' {
obj.typ = p.parseType()
}
p.expect('=')
switch p.tok {
case scanner.Ident:
// bool_lit
if p.lit != "true" && p.lit != "false" {
p.error("expected true or false")
}
x.typ = Typ[UntypedBool]
x.val = exact.MakeBool(p.lit == "true")
p.next()
case '-', scanner.Int:
// int_lit
x = p.parseNumber()
case '(':
// complex_lit or rune_lit
p.next()
if p.tok == scanner.Char {
p.next()
p.expect('+')
x = p.parseNumber()
x.typ = Typ[UntypedRune]
p.expect(')')
break
}
re := p.parseNumber()
p.expect('+')
im := p.parseNumber()
p.expectKeyword("i")
p.expect(')')
x.typ = Typ[UntypedComplex]
// TODO(gri) fix this
_, _ = re, im
x.val = exact.MakeInt64(0)
case scanner.Char:
// rune_lit
x.setConst(token.CHAR, p.lit)
p.next()
case scanner.String:
// string_lit
x.setConst(token.STRING, p.lit)
p.next()
default:
p.errorf("expected literal got %s", scanner.TokenString(p.tok))
}
if obj.typ == nil {
obj.typ = x.typ
}
assert(x.val != nil)
obj.val = x.val
}
// intConst returns an 'int' constant that evaluates to i.
// (i is an int64 in case the host is narrower than the target.)
func intConst(i int64) *Const {
return NewConst(exact.MakeInt64(i), tInt)
}
func (check *Checker) declStmt(decl ast.Decl) {
pkg := check.pkg
switch d := decl.(type) {
case *ast.BadDecl:
// ignore
case *ast.GenDecl:
var last *ast.ValueSpec // last ValueSpec with type or init exprs seen
for iota, spec := range d.Specs {
switch s := spec.(type) {
case *ast.ValueSpec:
switch d.Tok {
case token.CONST:
// determine which init exprs to use
switch {
case s.Type != nil || len(s.Values) > 0:
last = s
case last == nil:
last = new(ast.ValueSpec) // make sure last exists
}
// declare all constants
lhs := make([]*Const, len(s.Names))
for i, name := range s.Names {
obj := NewConst(name.Pos(), pkg, name.Name, nil, exact.MakeInt64(int64(iota)))
lhs[i] = obj
var init ast.Expr
if i < len(last.Values) {
init = last.Values[i]
}
check.constDecl(obj, last.Type, init)
}
check.arityMatch(s, last)
for i, name := range s.Names {
check.declare(check.scope, name, lhs[i])
}
case token.VAR:
lhs0 := make([]*Var, len(s.Names))
for i, name := range s.Names {
lhs0[i] = NewVar(name.Pos(), pkg, name.Name, nil)
}
// initialize all variables
for i, obj := range lhs0 {
var lhs []*Var
var init ast.Expr
switch len(s.Values) {
case len(s.Names):
// lhs and rhs match
init = s.Values[i]
case 1:
// rhs is expected to be a multi-valued expression
lhs = lhs0
init = s.Values[0]
default:
if i < len(s.Values) {
init = s.Values[i]
}
}
check.varDecl(obj, lhs, s.Type, init)
if len(s.Values) == 1 {
// If we have a single lhs variable we are done either way.
// If we have a single rhs expression, it must be a multi-
// valued expression, in which case handling the first lhs
// variable will cause all lhs variables to have a type
// assigned, and we are done as well.
if debug {
for _, obj := range lhs0 {
assert(obj.typ != nil)
}
}
break
}
}
check.arityMatch(s, nil)
// declare all variables
// (only at this point are the variable scopes (parents) set)
for i, name := range s.Names {
check.declare(check.scope, name, lhs0[i])
}
default:
check.invalidAST(s.Pos(), "invalid token %s", d.Tok)
}
case *ast.TypeSpec:
obj := NewTypeName(s.Name.Pos(), pkg, s.Name.Name, nil)
check.declare(check.scope, s.Name, obj)
check.typeDecl(obj, s.Type, nil, nil)
default:
check.invalidAST(s.Pos(), "const, type, or var declaration expected")
}
}
default:
check.invalidAST(d.Pos(), "unknown ast.Decl node %T", d)
}
}
// builtin type-checks a call to the built-in specified by id and
// returns true if the call is valid, with *x holding the result;
// but x.expr is not set. If the call is invalid, the result is
// false, and *x is undefined.
//
func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ bool) {
// append is the only built-in that permits the use of ... for the last argument
bin := predeclaredFuncs[id]
if call.Ellipsis.IsValid() && id != _Append {
check.invalidOp(call.Ellipsis, "invalid use of ... with built-in %s", bin.name)
check.use(call.Args...)
return
}
// For len(x) and cap(x) we need to know if x contains any function calls or
// receive operations. Save/restore current setting and set hasCallOrRecv to
// false for the evaluation of x so that we can check it afterwards.
// Note: We must do this _before_ calling unpack because unpack evaluates the
// first argument before we even call arg(x, 0)!
if id == _Len || id == _Cap {
defer func(b bool) {
check.hasCallOrRecv = b
}(check.hasCallOrRecv)
check.hasCallOrRecv = false
}
// determine actual arguments
var arg getter
nargs := len(call.Args)
switch id {
default:
// make argument getter
arg, nargs, _ = unpack(func(x *operand, i int) { check.expr(x, call.Args[i]) }, nargs, false)
// evaluate first argument, if present
if nargs > 0 {
arg(x, 0)
if x.mode == invalid {
return
}
}
case _Make, _New, _Offsetof, _Trace:
// arguments require special handling
}
// check argument count
{
msg := ""
if nargs < bin.nargs {
msg = "not enough"
} else if !bin.variadic && nargs > bin.nargs {
msg = "too many"
}
if msg != "" {
check.invalidOp(call.Rparen, "%s arguments for %s (expected %d, found %d)", msg, call, bin.nargs, nargs)
return
}
}
switch id {
case _Append:
// append(s S, x ...T) S, where T is the element type of S
// spec: "The variadic function append appends zero or more values x to s of type
// S, which must be a slice type, and returns the resulting slice, also of type S.
// The values x are passed to a parameter of type ...T where T is the element type
// of S and the respective parameter passing rules apply."
S := x.typ
var T Type
if s, _ := S.Underlying().(*Slice); s != nil {
T = s.elem
} else {
check.invalidArg(x.pos(), "%s is not a slice", x)
return
}
// remember arguments that have been evaluated already
alist := []operand{*x}
// spec: "As a special case, append also accepts a first argument assignable
// to type []byte with a second argument of string type followed by ... .
// This form appends the bytes of the string.
if nargs == 2 && call.Ellipsis.IsValid() && x.assignableTo(check.conf, NewSlice(UniverseByte)) {
arg(x, 1)
if x.mode == invalid {
return
}
if isString(x.typ) {
if check.Types != nil {
sig := makeSig(S, S, x.typ)
sig.variadic = true
check.recordBuiltinType(call.Fun, sig)
}
x.mode = value
x.typ = S
break
}
alist = append(alist, *x)
// fallthrough
}
// check general case by creating custom signature
sig := makeSig(S, S, NewSlice(T)) // []T required for variadic signature
sig.variadic = true
check.arguments(x, call, sig, func(x *operand, i int) {
// only evaluate arguments that have not been evaluated before
if i < len(alist) {
*x = alist[i]
return
}
arg(x, i)
}, nargs)
// ok to continue even if check.arguments reported errors
x.mode = value
x.typ = S
if check.Types != nil {
check.recordBuiltinType(call.Fun, sig)
}
case _Cap, _Len:
// cap(x)
// len(x)
mode := invalid
var typ Type
var val exact.Value
switch typ = implicitArrayDeref(x.typ.Underlying()); t := typ.(type) {
case *Basic:
if isString(t) && id == _Len {
if x.mode == constant {
mode = constant
val = exact.MakeInt64(int64(len(exact.StringVal(x.val))))
} else {
mode = value
}
}
case *Array:
mode = value
// spec: "The expressions len(s) and cap(s) are constants
// if the type of s is an array or pointer to an array and
// the expression s does not contain channel receives or
// function calls; in this case s is not evaluated."
if !check.hasCallOrRecv {
mode = constant
val = exact.MakeInt64(t.len)
}
case *Slice, *Chan:
mode = value
case *Map:
if id == _Len {
mode = value
}
}
if mode == invalid {
check.invalidArg(x.pos(), "%s for %s", x, bin.name)
return
}
x.mode = mode
x.typ = Typ[Int]
x.val = val
if check.Types != nil && mode != constant {
check.recordBuiltinType(call.Fun, makeSig(x.typ, typ))
}
case _Close:
// close(c)
c, _ := x.typ.Underlying().(*Chan)
if c == nil {
check.invalidArg(x.pos(), "%s is not a channel", x)
return
}
if c.dir == RecvOnly {
check.invalidArg(x.pos(), "%s must not be a receive-only channel", x)
return
}
x.mode = novalue
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(nil, c))
}
case _Complex:
// complex(x, y realT) complexT
if !check.complexArg(x) {
return
}
var y operand
arg(&y, 1)
if y.mode == invalid {
return
}
if !check.complexArg(&y) {
return
}
check.convertUntyped(x, y.typ)
if x.mode == invalid {
return
}
check.convertUntyped(&y, x.typ)
if y.mode == invalid {
return
}
if !Identical(x.typ, y.typ) {
check.invalidArg(x.pos(), "mismatched types %s and %s", x.typ, y.typ)
return
}
if x.mode == constant && y.mode == constant {
x.val = exact.BinaryOp(x.val, token.ADD, exact.MakeImag(y.val))
} else {
x.mode = value
}
realT := x.typ
complexT := Typ[Invalid]
switch realT.Underlying().(*Basic).kind {
case Float32:
complexT = Typ[Complex64]
case Float64:
complexT = Typ[Complex128]
case UntypedInt, UntypedRune, UntypedFloat:
if x.mode == constant {
realT = defaultType(realT).(*Basic)
complexT = Typ[UntypedComplex]
} else {
// untyped but not constant; probably because one
// operand is a non-constant shift of untyped lhs
realT = Typ[Float64]
complexT = Typ[Complex128]
}
default:
check.invalidArg(x.pos(), "float32 or float64 arguments expected")
return
}
x.typ = complexT
if check.Types != nil && x.mode != constant {
check.recordBuiltinType(call.Fun, makeSig(complexT, realT, realT))
}
if x.mode != constant {
// The arguments have now their final types, which at run-
// time will be materialized. Update the expression trees.
// If the current types are untyped, the materialized type
// is the respective default type.
// (If the result is constant, the arguments are never
// materialized and there is nothing to do.)
check.updateExprType(x.expr, realT, true)
check.updateExprType(y.expr, realT, true)
}
case _Copy:
// copy(x, y []T) int
var dst Type
if t, _ := x.typ.Underlying().(*Slice); t != nil {
dst = t.elem
}
var y operand
arg(&y, 1)
if y.mode == invalid {
return
}
var src Type
switch t := y.typ.Underlying().(type) {
case *Basic:
if isString(y.typ) {
src = UniverseByte
}
case *Slice:
src = t.elem
}
if dst == nil || src == nil {
check.invalidArg(x.pos(), "copy expects slice arguments; found %s and %s", x, &y)
return
}
if !Identical(dst, src) {
check.invalidArg(x.pos(), "arguments to copy %s and %s have different element types %s and %s", x, &y, dst, src)
return
}
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(Typ[Int], x.typ, y.typ))
}
x.mode = value
x.typ = Typ[Int]
case _Delete:
// delete(m, k)
m, _ := x.typ.Underlying().(*Map)
if m == nil {
check.invalidArg(x.pos(), "%s is not a map", x)
return
}
arg(x, 1) // k
if x.mode == invalid {
return
}
if !x.assignableTo(check.conf, m.key) {
check.invalidArg(x.pos(), "%s is not assignable to %s", x, m.key)
return
}
x.mode = novalue
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(nil, m, m.key))
}
case _Imag, _Real:
// imag(complexT) realT
// real(complexT) realT
if !isComplex(x.typ) {
check.invalidArg(x.pos(), "%s must be a complex number", x)
return
}
if x.mode == constant {
if id == _Real {
x.val = exact.Real(x.val)
} else {
x.val = exact.Imag(x.val)
}
} else {
x.mode = value
}
var k BasicKind
switch x.typ.Underlying().(*Basic).kind {
case Complex64:
k = Float32
case Complex128:
k = Float64
case UntypedComplex:
k = UntypedFloat
default:
unreachable()
}
if check.Types != nil && x.mode != constant {
check.recordBuiltinType(call.Fun, makeSig(Typ[k], x.typ))
}
x.typ = Typ[k]
case _Make:
// make(T, n)
// make(T, n, m)
// (no argument evaluated yet)
arg0 := call.Args[0]
T := check.typ(arg0)
if T == Typ[Invalid] {
return
}
var min int // minimum number of arguments
switch T.Underlying().(type) {
case *Slice:
min = 2
case *Map, *Chan:
min = 1
default:
check.invalidArg(arg0.Pos(), "cannot make %s; type must be slice, map, or channel", arg0)
return
}
if nargs < min || min+1 < nargs {
check.errorf(call.Pos(), "%s expects %d or %d arguments; found %d", call, min, min+1, nargs)
return
}
var sizes []int64 // constant integer arguments, if any
for _, arg := range call.Args[1:] {
if s, ok := check.index(arg, -1); ok && s >= 0 {
sizes = append(sizes, s)
}
}
if len(sizes) == 2 && sizes[0] > sizes[1] {
check.invalidArg(call.Args[1].Pos(), "length and capacity swapped")
// safe to continue
}
x.mode = value
x.typ = T
if check.Types != nil {
params := [...]Type{T, Typ[Int], Typ[Int]}
check.recordBuiltinType(call.Fun, makeSig(x.typ, params[:1+len(sizes)]...))
}
case _New:
// new(T)
// (no argument evaluated yet)
T := check.typ(call.Args[0])
if T == Typ[Invalid] {
return
}
x.mode = value
x.typ = &Pointer{base: T}
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(x.typ, T))
}
case _Panic:
// panic(x)
T := new(Interface)
if !check.assignment(x, T) {
assert(x.mode == invalid)
return
}
x.mode = novalue
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(nil, T))
}
case _Print, _Println:
// print(x, y, ...)
// println(x, y, ...)
var params []Type
if nargs > 0 {
params = make([]Type, nargs)
for i := 0; i < nargs; i++ {
if i > 0 {
arg(x, i) // first argument already evaluated
}
if !check.assignment(x, nil) {
assert(x.mode == invalid)
return
}
params[i] = x.typ
}
}
x.mode = novalue
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(nil, params...))
}
case _Recover:
// recover() interface{}
x.mode = value
x.typ = new(Interface)
if check.Types != nil {
check.recordBuiltinType(call.Fun, makeSig(x.typ))
}
case _Alignof:
// unsafe.Alignof(x T) uintptr
if !check.assignment(x, nil) {
assert(x.mode == invalid)
return
}
x.mode = constant
x.val = exact.MakeInt64(check.conf.alignof(x.typ))
x.typ = Typ[Uintptr]
// result is constant - no need to record signature
case _Offsetof:
// unsafe.Offsetof(x T) uintptr, where x must be a selector
// (no argument evaluated yet)
arg0 := call.Args[0]
selx, _ := unparen(arg0).(*ast.SelectorExpr)
if selx == nil {
check.invalidArg(arg0.Pos(), "%s is not a selector expression", arg0)
check.use(arg0)
return
}
check.expr(x, selx.X)
if x.mode == invalid {
return
}
base := derefStructPtr(x.typ)
sel := selx.Sel.Name
obj, index, indirect := LookupFieldOrMethod(base, false, check.pkg, sel)
switch obj.(type) {
case nil:
check.invalidArg(x.pos(), "%s has no single field %s", base, sel)
return
case *Func:
// TODO(gri) Using derefStructPtr may result in methods being found
// that don't actually exist. An error either way, but the error
// message is confusing. See: http://play.golang.org/p/al75v23kUy ,
// but go/types reports: "invalid argument: x.m is a method value".
check.invalidArg(arg0.Pos(), "%s is a method value", arg0)
return
}
if indirect {
check.invalidArg(x.pos(), "field %s is embedded via a pointer in %s", sel, base)
return
}
// TODO(gri) Should we pass x.typ instead of base (and indirect report if derefStructPtr indirected)?
check.recordSelection(selx, FieldVal, base, obj, index, false)
offs := check.conf.offsetof(base, index)
x.mode = constant
x.val = exact.MakeInt64(offs)
x.typ = Typ[Uintptr]
// result is constant - no need to record signature
case _Sizeof:
// unsafe.Sizeof(x T) uintptr
if !check.assignment(x, nil) {
assert(x.mode == invalid)
return
}
x.mode = constant
x.val = exact.MakeInt64(check.conf.sizeof(x.typ))
x.typ = Typ[Uintptr]
// result is constant - no need to record signature
case _Assert:
// assert(pred) causes a typechecker error if pred is false.
// The result of assert is the value of pred if there is no error.
// Note: assert is only available in self-test mode.
if x.mode != constant || !isBoolean(x.typ) {
check.invalidArg(x.pos(), "%s is not a boolean constant", x)
return
}
if x.val.Kind() != exact.Bool {
check.errorf(x.pos(), "internal error: value of %s should be a boolean constant", x)
return
}
if !exact.BoolVal(x.val) {
check.errorf(call.Pos(), "%s failed", call)
// compile-time assertion failure - safe to continue
}
// result is constant - no need to record signature
case _Trace:
// trace(x, y, z, ...) dumps the positions, expressions, and
// values of its arguments. The result of trace is the value
// of the first argument.
// Note: trace is only available in self-test mode.
// (no argument evaluated yet)
if nargs == 0 {
check.dump("%s: trace() without arguments", call.Pos())
x.mode = novalue
break
}
var t operand
x1 := x
for _, arg := range call.Args {
check.rawExpr(x1, arg, nil) // permit trace for types, e.g.: new(trace(T))
check.dump("%s: %s", x1.pos(), x1)
x1 = &t // use incoming x only for first argument
}
// trace is only available in test mode - no need to record signature
default:
unreachable()
}
return true
}
res := NewVar(token.NoPos, nil, "", Typ[String])
sig := &Signature{results: NewTuple(res)}
err := NewFunc(token.NoPos, nil, "Error", sig)
typ := &Named{underlying: NewInterface([]*Func{err}, nil), complete: true}
sig.recv = NewVar(token.NoPos, nil, "", typ)
def(NewTypeName(token.NoPos, nil, "error", typ))
}
var predeclaredConsts = [...]struct {
name string
kind BasicKind
val exact.Value
}{
{"true", UntypedBool, exact.MakeBool(true)},
{"false", UntypedBool, exact.MakeBool(false)},
{"iota", UntypedInt, exact.MakeInt64(0)},
}
func defPredeclaredConsts() {
for _, c := range predeclaredConsts {
def(NewConst(token.NoPos, nil, c.name, Typ[c.kind], c.val))
}
}
func defPredeclaredNil() {
def(&Nil{object{name: "nil", typ: Typ[UntypedNil]}})
}
// A builtinId is the id of a builtin function.
type builtinId int
// intLiteral returns an untyped integer literal that evaluates to i.
func intLiteral(i int64) *Literal {
return newLiteral(exact.MakeInt64(i), types.Typ[types.UntypedInt])
}
func (check *checker) declStmt(decl ast.Decl) {
pkg := check.pkg
switch d := decl.(type) {
case *ast.BadDecl:
// ignore
case *ast.GenDecl:
var last *ast.ValueSpec // last ValueSpec with type or init exprs seen
for iota, spec := range d.Specs {
switch s := spec.(type) {
case *ast.ValueSpec:
switch d.Tok {
case token.CONST:
// determine which init exprs to use
switch {
case s.Type != nil || len(s.Values) > 0:
last = s
case last == nil:
last = new(ast.ValueSpec) // make sure last exists
}
// declare all constants
lhs := make([]*Const, len(s.Names))
for i, name := range s.Names {
obj := NewConst(name.Pos(), pkg, name.Name, nil, exact.MakeInt64(int64(iota)))
lhs[i] = obj
var init ast.Expr
if i < len(last.Values) {
init = last.Values[i]
}
check.constDecl(obj, last.Type, init)
}
check.arityMatch(s, last)
for i, name := range s.Names {
check.declareObj(check.topScope, name, lhs[i])
}
case token.VAR:
// For varDecl called with a multiExpr we need the fully
// initialized lhs. Compute it in a separate pre-pass.
lhs := make([]*Var, len(s.Names))
for i, name := range s.Names {
lhs[i] = NewVar(name.Pos(), pkg, name.Name, nil)
}
// declare all variables
for i, obj := range lhs {
var init ast.Expr
switch len(s.Values) {
case len(s.Names):
// lhs and rhs match
init = s.Values[i]
case 1:
// rhs is expected to be a multi-valued expression
init = &multiExpr{lhs, s.Values, nil}
default:
if i < len(s.Values) {
init = s.Values[i]
}
}
check.varDecl(obj, s.Type, init)
}
check.arityMatch(s, nil)
for i, name := range s.Names {
check.declareObj(check.topScope, name, lhs[i])
}
default:
check.invalidAST(s.Pos(), "invalid token %s", d.Tok)
}
case *ast.TypeSpec:
obj := NewTypeName(s.Name.Pos(), pkg, s.Name.Name, nil)
check.declareObj(check.topScope, s.Name, obj)
check.typeDecl(obj, s.Type, nil, false)
default:
check.invalidAST(s.Pos(), "const, type, or var declaration expected")
}
}
default:
check.invalidAST(d.Pos(), "unknown ast.Decl node %T", d)
}
}
func (c *PkgContext) translateSimpleStmt(stmt ast.Stmt) string {
switch s := stmt.(type) {
case *ast.AssignStmt:
if s.Tok != token.ASSIGN && s.Tok != token.DEFINE {
var op token.Token
switch s.Tok {
case token.ADD_ASSIGN:
op = token.ADD
case token.SUB_ASSIGN:
op = token.SUB
case token.MUL_ASSIGN:
op = token.MUL
case token.QUO_ASSIGN:
op = token.QUO
case token.REM_ASSIGN:
op = token.REM
case token.AND_ASSIGN:
op = token.AND
case token.OR_ASSIGN:
op = token.OR
case token.XOR_ASSIGN:
op = token.XOR
case token.SHL_ASSIGN:
op = token.SHL
case token.SHR_ASSIGN:
op = token.SHR
case token.AND_NOT_ASSIGN:
op = token.AND_NOT
default:
panic(s.Tok)
}
var parts []string
var lhs ast.Expr
switch l := s.Lhs[0].(type) {
case *ast.IndexExpr:
lhsVar := c.newVariable("lhs")
indexVar := c.newVariable("index")
parts = append(parts, lhsVar+" = "+c.translateExpr(l.X))
parts = append(parts, indexVar+" = "+c.translateExpr(l.Index))
lhs = &ast.IndexExpr{
X: c.newIdent(lhsVar, c.info.Types[l.X]),
Index: c.newIdent(indexVar, c.info.Types[l.Index]),
}
c.info.Types[lhs] = c.info.Types[l]
case *ast.StarExpr:
lhsVar := c.newVariable("lhs")
parts = append(parts, lhsVar+" = "+c.translateExpr(l.X))
lhs = &ast.StarExpr{
X: c.newIdent(lhsVar, c.info.Types[l.X]),
}
c.info.Types[lhs] = c.info.Types[l]
default:
lhs = l
}
parenExpr := &ast.ParenExpr{
X: s.Rhs[0],
}
c.info.Types[parenExpr] = c.info.Types[s.Rhs[0]]
binaryExpr := &ast.BinaryExpr{
X: lhs,
Op: op,
Y: parenExpr,
}
c.info.Types[binaryExpr] = c.info.Types[s.Lhs[0]]
parts = append(parts, c.translateAssign(lhs, c.translateExpr(binaryExpr)))
return strings.Join(parts, ", ")
}
if s.Tok == token.DEFINE {
for _, lhs := range s.Lhs {
if !isBlank(lhs) {
c.info.Types[lhs] = c.info.Objects[lhs.(*ast.Ident)].Type()
}
}
}
switch {
case len(s.Lhs) == 1 && len(s.Rhs) == 1:
return c.translateAssign(s.Lhs[0], c.translateExprToType(s.Rhs[0], c.info.Types[s.Lhs[0]]))
case len(s.Lhs) > 1 && len(s.Rhs) == 1:
out := "Go$tuple = " + c.translateExpr(s.Rhs[0])
tuple := c.info.Types[s.Rhs[0]].(*types.Tuple)
for i, lhs := range s.Lhs {
if !isBlank(lhs) {
out += ", " + c.translateAssign(lhs, c.translateExprToType(c.newIdent(fmt.Sprintf("Go$tuple[%d]", i), tuple.At(i).Type()), c.info.Types[s.Lhs[i]]))
}
}
return out
case len(s.Lhs) == len(s.Rhs):
parts := make([]string, len(s.Rhs))
for i, rhs := range s.Rhs {
parts[i] = c.translateExprToType(rhs, c.info.Types[s.Lhs[i]])
}
out := "Go$tuple = [" + strings.Join(parts, ", ") + "]"
for i, lhs := range s.Lhs {
if !isBlank(lhs) {
out += ", " + c.translateAssign(lhs, fmt.Sprintf("Go$tuple[%d]", i))
}
}
return out
default:
panic("Invalid arity of AssignStmt.")
}
case *ast.IncDecStmt:
t := c.info.Types[s.X]
if iExpr, isIExpr := s.X.(*ast.IndexExpr); isIExpr {
switch u := c.info.Types[iExpr.X].Underlying().(type) {
case *types.Array:
t = u.Elem()
case *types.Slice:
t = u.Elem()
case *types.Map:
t = u.Elem()
}
}
tok := token.ADD_ASSIGN
if s.Tok == token.DEC {
tok = token.SUB_ASSIGN
}
one := &ast.BasicLit{
Kind: token.INT,
Value: "1",
}
c.info.Types[one] = t
c.info.Values[one] = exact.MakeInt64(1)
return c.translateSimpleStmt(&ast.AssignStmt{
Lhs: []ast.Expr{s.X},
Tok: tok,
Rhs: []ast.Expr{one},
})
case *ast.ExprStmt:
return c.translateExpr(s.X)
case *ast.DeclStmt:
var parts []string
for _, spec := range s.Decl.(*ast.GenDecl).Specs {
for _, singleSpec := range c.splitValueSpec(spec.(*ast.ValueSpec)) {
lhs := make([]ast.Expr, len(singleSpec.Names))
for i, name := range singleSpec.Names {
lhs[i] = name
}
parts = append(parts, c.translateSimpleStmt(&ast.AssignStmt{
Lhs: lhs,
Tok: token.DEFINE,
Rhs: singleSpec.Values,
}))
}
}
return strings.Join(parts, ", ")
case *ast.SendStmt:
return `throw new Go$Panic("Statement not supported: send")`
default:
panic(fmt.Sprintf("Unhandled statement: %T\n", s))
}
}