Add all loop variables inside a loop (#49)

exec.go

@@ -342,10 +342,28 @@ func (s *state) walkForNode(node *parse.ForNode) error {
 		defer s.scope.pop()
 
 		if kn != "" {
-			s.scope.Set(kn, k)
+			s.scope.setLocal(kn, k)
 		}
-		s.scope.Set(vn, v)
-		s.scope.Set("loop", l)
+		s.scope.setLocal(vn, v)
+		loopValue := map[string]Value{
+			"Last":      l.Last,
+			"Index":     l.Index,
+			"Index0":    l.Index0,
+			"last":      l.Last,
+			"index":     l.Index,
+			"index0":    l.Index0,
+			"revindex":  l.Revindex,
+			"revindex0": l.Revindex0,
+			"first":     l.First,
+			"length":    l.Length,
+		}
+
+		parent, hasParent := s.scope.Get("loop")
+		if hasParent {
+			loopValue["parent"] = parent
+		}
+
+		s.scope.setLocal("loop", loopValue)
 
 		err := s.walk(node.Body)
 		if err != nil {

exec_test.go

@@ -43,10 +43,27 @@ var tests = []execTest{
 	{"Chained attributes", `{{ entity.attr.Name }}`, map[string]Value{"entity": map[string]Value{"attr": struct{ Name string }{"Tyler"}}}, expect(`Tyler`)},
 	{"Attribute method call", `{{ entity.Name('lower') }}`, map[string]Value{"entity": &testPerson{"Johnny"}}, expect(`lowerJohnny`)},
 	{"For loop", `{% for i in 1..3 %}{{ i }}{% endfor %}`, emptyCtx, expect(`123`)},
+	{
+		"For loop with inner loop",
+		`{% for i in test %}{% for j in i %}{{ j }}{{ loop.index }}{{ loop.parent.index }}{% if loop.first %},{% endif %}{% if loop.last %};{% endif %}{% endfor %}{% if loop.first %}f{% endif %}{% if loop.last %}l{% endif %}:{% endfor %}`,
+		map[string]Value{
+			"test": [][]int{
+				{1, 2, 3},
+				{4, 5, 6},
+				{7, 8, 9}},
+		},
+		expect(`111,221331;f:412,522632;:713,823933;l:`),
+	},
+	{
+		"For loop variables",
+		`{% for i in 1..3 %}{{ i }}{{ loop.index }}{{ loop.index0 }}{{ loop.revindex }}{{ loop.revindex0 }}{{ loop.length }}{% if loop.first %}f{% endif %}{% if loop.last %}l{% endif %}{% endfor %}`,
+		emptyCtx,
+		expect(`110323f221213332103l`),
+	},
 	{"For else", `{% for i in emptySet %}{{ i }}{% else %}No results.{% endfor %}`, map[string]Value{"emptySet": []int{}}, expect(`No results.`)},
 	{
 		"For map",
-		`{% for k, v in data %}Record {{ loop.Index }}: {{ k }}: {{ v }}{% if not loop.Last %} - {% endif %}{% endfor %}`,
+		`{% for k, v in data %}Record {{ loop.index }}: {{ k }}: {{ v }}{% if not loop.last %} - {% endif %}{% endfor %}`,
 		map[string]Value{"data": map[string]float64{"Group A": 5.12, "Group B": 5.09}},
 		optionExpect(`Record 1: Group A: 5.12 - Record 2: Group B: 5.09`, `Record 1: Group B: 5.09 - Record 2: Group A: 5.12`),
 	},

value.go

@@ -291,9 +291,13 @@ type Iteratee func(k, v Value, l Loop) (brk bool, err error)
 
 // Loop contains metadata about the current state of a loop.
 type Loop struct {
-	Last   bool
-	Index  int
-	Index0 int
+	Last      bool
+	Index     int
+	Index0    int
+	Revindex  int
+	Revindex0 int
+	First     bool
+	Length    int
 }
 
 // IsArray returns true if the given Value is a slice or array.
@@ -334,7 +338,15 @@ func Iterate(val Value, it Iteratee) (int, error) {
 	switch r.Kind() {
 	case reflect.Slice, reflect.Array:
 		ln := r.Len()
-		l := Loop{ln == 1, 1, 0}
+		l := Loop{
+			ln == 1,
+			1,
+			0,
+			ln,
+			ln - 1,
+			true,
+			ln,
+		}
 		for i := 0; i < ln; i++ {
 			v := r.Index(i)
 			brk, err := it(i, v.Interface(), l)
@@ -345,12 +357,23 @@ func Iterate(val Value, it Iteratee) (int, error) {
 			l.Index++
 			l.Index0++
 			l.Last = ln == l.Index
+			l.Revindex--
+			l.Revindex0--
+			l.First = false
 		}
 		return ln, nil
 	case reflect.Map:
 		keys := r.MapKeys()
 		ln := r.Len()
-		l := Loop{ln == 1, 1, 0}
+		l := Loop{
+			ln == 1,
+			1,
+			0,
+			ln,
+			ln - 1,
+			true,
+			ln,
+		}
 		for i, k := range keys {
 			v := r.MapIndex(k)
 			brk, err := it(k.Interface(), v.Interface(), l)
@@ -361,6 +384,9 @@ func Iterate(val Value, it Iteratee) (int, error) {
 			l.Index++
 			l.Index0++
 			l.Last = ln == l.Index
+			l.Revindex--
+			l.Revindex0--
+			l.First = false
 		}
 		return ln, nil
 	default:
@@ -368,7 +394,7 @@ func Iterate(val Value, it Iteratee) (int, error) {
 	}
 }
 
-// Len returns the length of Value.
+// Len returns the Length of Value.
 func Len(val Value) (int, error) {
 	if val == nil {
 		return 0, nil
@@ -378,7 +404,7 @@ func Len(val Value) (int, error) {
 	case reflect.Slice, reflect.Array, reflect.Map:
 		return r.Len(), nil
 	}
-	return 0, fmt.Errorf(`stick: could not get length of %s "%v"`, r.Kind(), val)
+	return 0, fmt.Errorf(`stick: could not get Length of %s "%v"`, r.Kind(), val)
 }
 
 // Equal returns true if the two Values are considered equal.