func (this DepthWalker) Visit(node ast.Node) ast.Visitor {
if node == nil {
return this + 1
}
buffer := ""
for i := 0; i < int(this); i++ {
buffer += " "
}
fmt.Printf("%sPos: %d %s\n", buffer, node.Pos(), AllSources.Position(node.Pos()))
fmt.Printf("%sEnd: %d %s\n", buffer, node.End(), AllSources.Position(node.End()))
fmt.Printf("%s%T\n", buffer, node)
fmt.Printf("%s%v\n", buffer, node)
if e, ok := node.(ast.Expr); ok {
obj, typ := types.ExprType(e, LocalImporter)
fmt.Printf("%s%v\n", buffer, obj)
fmt.Printf("%s%v\n", buffer, typ)
}
fmt.Println()
switch n := node.(type) {
}
return this + 1
}
func exprType(n ast.Node, expectTuple bool, pkg string, importer Importer) (xobj *ast.Object, typ Type) {
debugp("exprType tuple:%v pkg:%s %T %v [", expectTuple, pkg, n, pretty{n})
defer func() {
debugp("] -> %p, %v", xobj, typ)
}()
switch n := n.(type) {
case nil:
case *ast.Ident:
obj := n.Obj
if obj == nil || obj.Kind == ast.Bad {
break
}
// A type object represents itself.
if obj.Kind == ast.Typ {
// Objects in the universal scope don't live
// in any package.
if parser.Universe.Lookup(obj.Name) == obj {
pkg = ""
}
return obj, Type{n, obj.Kind, pkg}
}
expr, typ := splitDecl(obj, n)
switch {
case typ != nil:
_, t := exprType(typ, false, pkg, importer)
if t.Kind != ast.Bad {
t.Kind = obj.Kind
}
return obj, t
case expr != nil:
_, t := exprType(expr, false, pkg, importer)
if t.Kind == ast.Typ {
debugp("expected value, got type %v", t)
t = badType
}
return obj, t
default:
switch n.Obj {
case falseIdent.Obj, trueIdent.Obj:
return obj, Type{boolIdent, ast.Con, ""}
case iotaIdent.Obj:
return obj, Type{intIdent, ast.Con, ""}
default:
return obj, Type{}
}
}
case *ast.LabeledStmt:
return n.Label.Obj, Type{n, ast.Lbl, pkg}
case *ast.ImportSpec:
return nil, Type{n, ast.Pkg, ""}
case *ast.ParenExpr:
return exprType(n.X, expectTuple, pkg, importer)
case *ast.CompositeLit:
return nil, certify(n.Type, ast.Var, pkg, importer)
case *ast.FuncLit:
return nil, certify(n.Type, ast.Var, pkg, importer)
case *ast.SelectorExpr:
_, t := exprType(n.X, false, pkg, importer)
// TODO: method expressions. when t.Kind == ast.Typ,
// mutate a method declaration into a function with
// the receiver as first argument
if t.Kind == ast.Bad {
break
}
obj := t.Member(n.Sel.Name, importer)
if obj == nil {
return nil, badType
}
if t.Kind == ast.Pkg {
eobj, et := exprType(&ast.Ident{Name: obj.Name, Obj: obj}, false, t.Pkg, importer)
et.Pkg = litToString(t.Node.(*ast.ImportSpec).Path)
return eobj, et
}
// a method turns into a function type;
// the number of formal arguments depends
// on the class of the receiver expression.
if fd, ismethod := obj.Decl.(*ast.FuncDecl); ismethod {
if t.Kind == ast.Typ {
return obj, certify(methodExpr(fd), ast.Fun, t.Pkg, importer)
}
return obj, certify(fd.Type, ast.Fun, t.Pkg, importer)
} else if obj.Kind == ast.Typ {
return obj, certify(&ast.Ident{Name: obj.Name, Obj: obj}, ast.Typ, t.Pkg, importer)
}
_, typ := splitDecl(obj, nil)
return obj, certify(typ, obj.Kind, t.Pkg, importer)
case *ast.FuncDecl:
return nil, certify(methodExpr(n), ast.Fun, pkg, importer)
case *ast.IndexExpr:
_, t0 := exprType(n.X, false, pkg, importer)
t := t0.Underlying(true, importer)
switch n := t.Node.(type) {
case *ast.ArrayType:
return nil, certify(n.Elt, ast.Var, t.Pkg, importer)
case *ast.MapType:
t := certify(n.Value, ast.Var, t.Pkg, importer)
if expectTuple {
return nil, Type{MultiValue{[]ast.Expr{t.Node.(ast.Expr), predecl("bool")}}, ast.Var, t.Pkg}
}
return nil, t
}
case *ast.SliceExpr:
_, typ := exprType(n.X, false, pkg, importer)
return nil, typ
case *ast.CallExpr:
switch exprName(n.Fun) {
case makeIdent.Obj:
if len(n.Args) > 0 {
return nil, certify(n.Args[0], ast.Var, pkg, importer)
}
case newIdent.Obj:
if len(n.Args) > 0 {
t := certify(n.Args[0], ast.Var, pkg, importer)
if t.Kind != ast.Bad {
return nil, Type{&ast.StarExpr{n.Pos(), t.Node.(ast.Expr)}, ast.Var, t.Pkg}
}
}
default:
if _, fntype := exprType(n.Fun, false, pkg, importer); fntype.Kind != ast.Bad {
// A type cast transforms a type expression
// into a value expression.
if fntype.Kind == ast.Typ {
fntype.Kind = ast.Var
// Preserve constness if underlying expr is constant.
if len(n.Args) == 1 {
_, argtype := exprType(n.Args[0], false, pkg, importer)
if argtype.Kind == ast.Con {
fntype.Kind = ast.Con
}
}
return nil, fntype
}
// A function call operates on the underlying type,
t := fntype.Underlying(true, importer)
if fn, ok := t.Node.(*ast.FuncType); ok {
return nil, certify(fields2type(fn.Results), ast.Var, t.Pkg, importer)
}
}
}
case *ast.StarExpr:
if _, t := exprType(n.X, false, pkg, importer); t.Kind != ast.Bad {
if t.Kind == ast.Typ {
return nil, Type{&ast.StarExpr{n.Pos(), t.Node.(ast.Expr)}, ast.Typ, t.Pkg}
}
if n, ok := t.Node.(*ast.StarExpr); ok {
return nil, certify(n.X, ast.Var, t.Pkg, importer)
}
}
case *ast.TypeAssertExpr:
t := certify(n.Type, ast.Var, pkg, importer)
if expectTuple && t.Kind != ast.Bad {
return nil, Type{MultiValue{[]ast.Expr{t.Node.(ast.Expr), predecl("bool")}}, ast.Var, t.Pkg}
}
return nil, t
case *ast.UnaryExpr:
if _, t := exprType(n.X, false, pkg, importer); t.Kind != ast.Bad {
u := t.Underlying(true, importer)
switch n.Op {
case token.ARROW:
if ct, ok := u.Node.(*ast.ChanType); ok {
t := certify(ct.Value, ast.Var, u.Pkg, importer)
if expectTuple && t.Kind != ast.Bad {
return nil, Type{MultiValue{[]ast.Expr{t.Node.(ast.Expr), predecl("bool")}}, ast.Var, t.Pkg}
}
return nil, certify(ct.Value, ast.Var, u.Pkg, importer)
}
case token.RANGE:
switch n := u.Node.(type) {
case *ast.ArrayType:
if expectTuple {
return nil, Type{MultiValue{[]ast.Expr{predecl("int"), n.Elt}}, ast.Var, u.Pkg}
}
return nil, Type{predecl("bool"), ast.Var, ""}
case *ast.MapType:
if expectTuple {
return nil, Type{MultiValue{[]ast.Expr{n.Key, n.Value}}, ast.Var, u.Pkg}
}
return nil, certify(n.Key, ast.Var, u.Pkg, importer)
case *ast.ChanType:
return nil, certify(n.Value, ast.Var, u.Pkg, importer)
}
case token.AND:
if t.Kind == ast.Var {
return nil, Type{&ast.StarExpr{n.Pos(), t.Node.(ast.Expr)}, ast.Var, t.Pkg}
}
case token.NOT:
return nil, Type{predecl("bool"), t.Kind, ""}
default:
return nil, t
}
}
case *ast.BinaryExpr:
switch n.Op {
case token.LSS, token.EQL, token.GTR, token.NEQ, token.LEQ, token.GEQ, token.ARROW, token.LOR, token.LAND:
_, t := exprType(n.X, false, pkg, importer)
if t.Kind == ast.Con {
_, t = exprType(n.Y, false, pkg, importer)
}
return nil, Type{predecl("bool"), t.Kind, ""}
case token.ADD, token.SUB, token.MUL, token.QUO, token.REM, token.AND, token.AND_NOT, token.XOR:
_, tx := exprType(n.X, false, pkg, importer)
_, ty := exprType(n.Y, false, pkg, importer)
switch {
case tx.Kind == ast.Bad || ty.Kind == ast.Bad:
case !isNamedType(tx, importer):
return nil, ty
case !isNamedType(ty, importer):
return nil, tx
}
// could check type equality
return nil, tx
case token.SHL, token.SHR:
_, typ := exprType(n.X, false, pkg, importer)
return nil, typ
}
case *ast.BasicLit:
var id *ast.Ident
switch n.Kind {
case token.STRING:
id = stringIdent
case token.INT, token.CHAR:
id = intIdent
case token.FLOAT:
id = floatIdent
default:
debugp("unknown constant type %v", n.Kind)
}
if id != nil {
return nil, Type{id, ast.Con, ""}
}
case *ast.StructType, *ast.ChanType, *ast.MapType, *ast.ArrayType, *ast.InterfaceType, *ast.FuncType:
return nil, Type{n.(ast.Node), ast.Typ, pkg}
case MultiValue:
return nil, Type{n, ast.Typ, pkg}
case *exprIndex:
_, t := exprType(n.x, true, pkg, importer)
if t.Kind != ast.Bad {
if ts, ok := t.Node.(MultiValue); ok {
if n.i < len(ts.Types) {
return nil, certify(ts.Types[n.i], ast.Var, t.Pkg, importer)
}
}
}
case *ast.Ellipsis:
t := certify(n.Elt, ast.Var, pkg, importer)
if t.Kind != ast.Bad {
return nil, Type{&ast.ArrayType{n.Pos(), nil, t.Node.(ast.Expr)}, ast.Var, t.Pkg}
}
default:
panic(fmt.Sprintf("unknown type %T", n))
}
return nil, badType
}