Clean up some TODOs

Some were stale, some were transformed into issues, some were fixed

ast/ast.go

@@ -468,8 +468,6 @@ type ObjectField struct {
 	Expr2, Expr3  Node        // In scope of the object (can see self).
 }
 
-// TODO(jbeda): Add the remaining constructor helpers here
-
 func ObjectFieldLocalNoMethod(id *Identifier, body Node) ObjectField {
 	return ObjectField{ObjectLocal, ObjectFieldVisible, false, false, nil, nil, id, nil, false, body, nil}
 }

error_formatter.go

@@ -25,7 +25,6 @@ import (
 )
 
 type ErrorFormatter struct {
-	// TODO(sbarzowski) use this
 	// MaxStackTraceSize  is the maximum length of stack trace before cropping
 	MaxStackTraceSize int
 

testdata/insuper2.golden

@@ -1,5 +1,3 @@
-testdata/insuper2:1:11-13 Expected token OPERATOR but got (in, "in")
-
-{ } { "x" in super }
-
-
+{
+   "x": false
+}

testdata/insuper2.jsonnet

@@ -1 +1 @@
-{ } { "x" in super }
+{ } { x: "x" in super }

testdata/missing_super.golden

@@ -0,0 +1,10 @@
+RUNTIME ERROR: Attempt to use super when there is no super class.
+-------------------------------------------------
+	testdata/missing_super:1:6-11	object <anonymous>
+
+{ x: super.x }
+
+-------------------------------------------------
+	During manifestation	
+
+

testdata/missing_super.jsonnet

@@ -0,0 +1 @@
+{ x: super.x }

testdata/object_invariant7.golden

@@ -1,4 +1,4 @@
-RUNTIME ERROR: Field does not exist: x
+RUNTIME ERROR: Attempt to use super when there is no super class.
 -------------------------------------------------
 	testdata/object_invariant7:1:16-21	object <anonymous>
 

thunks.go

@@ -100,8 +100,6 @@ func (th *callThunk) getValue(i *interpreter, trace *TraceElement) (value, error
 // the first evaluation.
 // Note: All potentialValues are required to provide the same value every time,
 // so it's only there for efficiency.
-// TODO(sbarzowski) better name?
-// TODO(sbarzowski) force use cached/ready everywhere? perhaps an interface tag?
 // TODO(sbarzowski) investigate efficiency of various representations
 type cachedThunk struct {
 	pv evaluable

value.go

@@ -166,13 +166,14 @@ func int64ToValue(i int64) *valueNumber {
 	return makeValueNumber(float64(i))
 }
 
-// TODO(dcunnin): Maybe intern values null, true, and false?
 type valueNull struct {
 	valueBase
 }
 
+var nullValue valueNull
+
 func makeValueNull() *valueNull {
-	return &valueNull{}
+	return &nullValue
 }
 
 func (*valueNull) typename() string {
@@ -274,9 +275,8 @@ func args(xs ...potentialValue) callArguments {
 // Object is a value that allows indexing (taking a value of a field)
 // and combining through mixin inheritence (operator +).
 //
-// Accessing a field multiple times results in multiple evaluations.
-// TODO(sbarzowski) This can be very easily avoided and currently innocent looking
-// 					code may be in fact exponential.
+// Note that every time a field is indexed it evaluates it again, there is
+// no caching of field values. See: https://github.com/google/go-jsonnet/issues/113
 type valueObject interface {
 	value
 	inheritanceSize() int
@@ -471,7 +471,6 @@ type unboundField interface {
 // This represenation allows us to implement "+" in O(1),
 // but requires going through the tree and trying subsequent leafs for field access.
 //
-// TODO(sbarzowski) consider other representations (this representation was chosen to stay close to C++ version)
 type valueExtendedObject struct {
 	valueObjectBase
 	left, right          valueObject
@@ -515,7 +514,6 @@ func findField(curr value, minSuperDepth int, f string) (*valueSimpleObjectField
 				return &field, curr.upValues, 0
 			}
 		}
-		// TODO(sbarzowski) add handling of "Attempt to use super when there is no super class."
 		return nil, nil, 0
 	default:
 		panic(fmt.Sprintf("Unknown object type %#v", curr))
@@ -527,6 +525,9 @@ func objectIndex(e *evaluator, sb selfBinding, fieldName string) (value, error)
 	if err != nil {
 		return nil, err
 	}
+	if sb.superDepth >= sb.self.inheritanceSize() {
+		return nil, e.Error("Attempt to use super when there is no super class.")
+	}
 	objp := tryObjectIndex(sb, fieldName, withHidden)
 	if objp == nil {
 		return nil, e.Error(fmt.Sprintf("Field does not exist: %s", fieldName))

vm.go

@@ -28,8 +28,6 @@ import (
 // Note: There are no garbage collection params because we're using the native
 // Go garbage collector.
 
-// TODO(sbarzowski) prepare API that maps 1-1 to libjsonnet api
-
 // VM is the core interpreter and is the touchpoint used to parse and execute
 // Jsonnet.
 type VM struct {
@@ -40,7 +38,6 @@ type VM struct {
 	ef       ErrorFormatter
 }
 
-// TODO(sbarzowski) actually support these
 // External variable (or code) provided before execution
 type vmExt struct {
 	value  string // what is it?