Export members of EvalNodeHelper to facilitate usage in external functions (#7860)

Signed-off-by: Vijay Samuel <vjsamuel@ebay.com>

promql/engine.go

@@ -792,13 +792,13 @@ func (ev *evaluator) Eval(expr parser.Expr) (v parser.Value, ws storage.Warnings
 // EvalNodeHelper stores extra information and caches for evaluating a single node across steps.
 type EvalNodeHelper struct {
 	// Evaluation timestamp.
-	ts int64
+	Ts int64
 	// Vector that can be used for output.
-	out Vector
+	Out Vector
 
 	// Caches.
-	// dropMetricName and label_*.
-	dmn map[uint64]labels.Labels
+	// DropMetricName and label_*.
+	Dmn map[uint64]labels.Labels
 	// signatureFunc.
 	sigf map[string]string
 	// funcHistogramQuantile.
@@ -816,24 +816,24 @@ type EvalNodeHelper struct {
 	resultMetric map[string]labels.Labels
 }
 
-// dropMetricName is a cached version of dropMetricName.
-func (enh *EvalNodeHelper) dropMetricName(l labels.Labels) labels.Labels {
-	if enh.dmn == nil {
-		enh.dmn = make(map[uint64]labels.Labels, len(enh.out))
+// DropMetricName is a cached version of DropMetricName.
+func (enh *EvalNodeHelper) DropMetricName(l labels.Labels) labels.Labels {
+	if enh.Dmn == nil {
+		enh.Dmn = make(map[uint64]labels.Labels, len(enh.Out))
 	}
 	h := l.Hash()
-	ret, ok := enh.dmn[h]
+	ret, ok := enh.Dmn[h]
 	if ok {
 		return ret
 	}
 	ret = dropMetricName(l)
-	enh.dmn[h] = ret
+	enh.Dmn[h] = ret
 	return ret
 }
 
 func (enh *EvalNodeHelper) signatureFunc(on bool, names ...string) func(labels.Labels) string {
 	if enh.sigf == nil {
-		enh.sigf = make(map[string]string, len(enh.out))
+		enh.sigf = make(map[string]string, len(enh.Out))
 	}
 	f := signatureFunc(on, enh.lblBuf, names...)
 	return func(l labels.Labels) string {
@@ -885,7 +885,7 @@ func (ev *evaluator) rangeEval(f func([]parser.Value, *EvalNodeHelper) (Vector,
 			biggestLen = len(matrixes[i])
 		}
 	}
-	enh := &EvalNodeHelper{out: make(Vector, 0, biggestLen)}
+	enh := &EvalNodeHelper{Out: make(Vector, 0, biggestLen)}
 	seriess := make(map[uint64]Series, biggestLen) // Output series by series hash.
 	tempNumSamples := ev.currentSamples
 	for ts := ev.startTimestamp; ts <= ev.endTimestamp; ts += ev.interval {
@@ -916,12 +916,12 @@ func (ev *evaluator) rangeEval(f func([]parser.Value, *EvalNodeHelper) (Vector,
 			args[i] = vectors[i]
 		}
 		// Make the function call.
-		enh.ts = ts
+		enh.Ts = ts
 		result, ws := f(args, enh)
 		if result.ContainsSameLabelset() {
 			ev.errorf("vector cannot contain metrics with the same labelset")
 		}
-		enh.out = result[:0] // Reuse result vector.
+		enh.Out = result[:0] // Reuse result vector.
 		warnings = append(warnings, ws...)
 
 		ev.currentSamples += len(result)
@@ -1030,7 +1030,7 @@ func (ev *evaluator) eval(expr parser.Expr) (parser.Value, storage.Warnings) {
 			vs, ok := e.Args[0].(*parser.VectorSelector)
 			if ok {
 				return ev.rangeEval(func(v []parser.Value, enh *EvalNodeHelper) (Vector, storage.Warnings) {
-					val, ws := ev.vectorSelector(vs, enh.ts)
+					val, ws := ev.vectorSelector(vs, enh.Ts)
 					return call([]parser.Value{val}, e.Args, enh), ws
 				})
 			}
@@ -1101,7 +1101,7 @@ func (ev *evaluator) eval(expr parser.Expr) (parser.Value, storage.Warnings) {
 		points := getPointSlice(16)
 		inMatrix := make(Matrix, 1)
 		inArgs[matrixArgIndex] = inMatrix
-		enh := &EvalNodeHelper{out: make(Vector, 0, 1)}
+		enh := &EvalNodeHelper{Out: make(Vector, 0, 1)}
 		// Process all the calls for one time series at a time.
 		it := storage.NewBuffer(selRange)
 		for i, s := range selVS.Series {
@@ -1134,10 +1134,10 @@ func (ev *evaluator) eval(expr parser.Expr) (parser.Value, storage.Warnings) {
 					continue
 				}
 				inMatrix[0].Points = points
-				enh.ts = ts
+				enh.Ts = ts
 				// Make the function call.
 				outVec := call(inArgs, e.Args, enh)
-				enh.out = outVec[:0]
+				enh.Out = outVec[:0]
 				if len(outVec) > 0 {
 					ss.Points = append(ss.Points, Point{V: outVec[0].Point.V, T: ts})
 				}
@@ -1227,7 +1227,7 @@ func (ev *evaluator) eval(expr parser.Expr) (parser.Value, storage.Warnings) {
 		case lt == parser.ValueTypeScalar && rt == parser.ValueTypeScalar:
 			return ev.rangeEval(func(v []parser.Value, enh *EvalNodeHelper) (Vector, storage.Warnings) {
 				val := scalarBinop(e.Op, v[0].(Vector)[0].Point.V, v[1].(Vector)[0].Point.V)
-				return append(enh.out, Sample{Point: Point{V: val}}), nil
+				return append(enh.Out, Sample{Point: Point{V: val}}), nil
 			}, e.LHS, e.RHS)
 		case lt == parser.ValueTypeVector && rt == parser.ValueTypeVector:
 			switch e.Op {
@@ -1262,7 +1262,7 @@ func (ev *evaluator) eval(expr parser.Expr) (parser.Value, storage.Warnings) {
 
 	case *parser.NumberLiteral:
 		return ev.rangeEval(func(v []parser.Value, enh *EvalNodeHelper) (Vector, storage.Warnings) {
-			return append(enh.out, Sample{Point: Point{V: e.Val}}), nil
+			return append(enh.Out, Sample{Point: Point{V: e.Val}}), nil
 		})
 
 	case *parser.VectorSelector:
@@ -1530,10 +1530,10 @@ func (ev *evaluator) VectorAnd(lhs, rhs Vector, matching *parser.VectorMatching,
 	for _, ls := range lhs {
 		// If there's a matching entry in the right-hand side Vector, add the sample.
 		if _, ok := rightSigs[sigf(ls.Metric)]; ok {
-			enh.out = append(enh.out, ls)
+			enh.Out = append(enh.Out, ls)
 		}
 	}
-	return enh.out
+	return enh.Out
 }
 
 func (ev *evaluator) VectorOr(lhs, rhs Vector, matching *parser.VectorMatching, enh *EvalNodeHelper) Vector {
@@ -1546,15 +1546,15 @@ func (ev *evaluator) VectorOr(lhs, rhs Vector, matching *parser.VectorMatching,
 	// Add everything from the left-hand-side Vector.
 	for _, ls := range lhs {
 		leftSigs[sigf(ls.Metric)] = struct{}{}
-		enh.out = append(enh.out, ls)
+		enh.Out = append(enh.Out, ls)
 	}
 	// Add all right-hand side elements which have not been added from the left-hand side.
 	for _, rs := range rhs {
 		if _, ok := leftSigs[sigf(rs.Metric)]; !ok {
-			enh.out = append(enh.out, rs)
+			enh.Out = append(enh.Out, rs)
 		}
 	}
-	return enh.out
+	return enh.Out
 }
 
 func (ev *evaluator) VectorUnless(lhs, rhs Vector, matching *parser.VectorMatching, enh *EvalNodeHelper) Vector {
@@ -1570,10 +1570,10 @@ func (ev *evaluator) VectorUnless(lhs, rhs Vector, matching *parser.VectorMatchi
 
 	for _, ls := range lhs {
 		if _, ok := rightSigs[sigf(ls.Metric)]; !ok {
-			enh.out = append(enh.out, ls)
+			enh.Out = append(enh.Out, ls)
 		}
 	}
-	return enh.out
+	return enh.Out
 }
 
 // VectorBinop evaluates a binary operation between two Vectors, excluding set operators.
@@ -1592,7 +1592,7 @@ func (ev *evaluator) VectorBinop(op parser.ItemType, lhs, rhs Vector, matching *
 
 	// All samples from the rhs hashed by the matching label/values.
 	if enh.rightSigs == nil {
-		enh.rightSigs = make(map[string]Sample, len(enh.out))
+		enh.rightSigs = make(map[string]Sample, len(enh.Out))
 	} else {
 		for k := range enh.rightSigs {
 			delete(enh.rightSigs, k)
@@ -1657,7 +1657,7 @@ func (ev *evaluator) VectorBinop(op parser.ItemType, lhs, rhs Vector, matching *
 		}
 		metric := resultMetric(ls.Metric, rs.Metric, op, matching, enh)
 		if returnBool {
-			metric = enh.dropMetricName(metric)
+			metric = enh.DropMetricName(metric)
 		}
 		insertedSigs, exists := matchedSigs[sig]
 		if matching.Card == parser.CardOneToOne {
@@ -1680,12 +1680,12 @@ func (ev *evaluator) VectorBinop(op parser.ItemType, lhs, rhs Vector, matching *
 			insertedSigs[insertSig] = struct{}{}
 		}
 
-		enh.out = append(enh.out, Sample{
+		enh.Out = append(enh.Out, Sample{
 			Metric: metric,
 			Point:  Point{V: value},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 func signatureFunc(on bool, b []byte, names ...string) func(labels.Labels) string {
@@ -1704,7 +1704,7 @@ func signatureFunc(on bool, b []byte, names ...string) func(labels.Labels) strin
 // binary operation and the matching options.
 func resultMetric(lhs, rhs labels.Labels, op parser.ItemType, matching *parser.VectorMatching, enh *EvalNodeHelper) labels.Labels {
 	if enh.resultMetric == nil {
-		enh.resultMetric = make(map[string]labels.Labels, len(enh.out))
+		enh.resultMetric = make(map[string]labels.Labels, len(enh.Out))
 	}
 
 	if enh.lb == nil {
@@ -1784,12 +1784,12 @@ func (ev *evaluator) VectorscalarBinop(op parser.ItemType, lhs Vector, rhs Scala
 		if keep {
 			lhsSample.V = value
 			if shouldDropMetricName(op) || returnBool {
-				lhsSample.Metric = enh.dropMetricName(lhsSample.Metric)
+				lhsSample.Metric = enh.DropMetricName(lhsSample.Metric)
 			}
-			enh.out = append(enh.out, lhsSample)
+			enh.Out = append(enh.Out, lhsSample)
 		}
 	}
-	return enh.out
+	return enh.Out
 }
 
 func dropMetricName(l labels.Labels) labels.Labels {
@@ -2069,7 +2069,7 @@ func (ev *evaluator) aggregation(op parser.ItemType, grouping []string, without
 			// The heap keeps the lowest value on top, so reverse it.
 			sort.Sort(sort.Reverse(aggr.heap))
 			for _, v := range aggr.heap {
-				enh.out = append(enh.out, Sample{
+				enh.Out = append(enh.Out, Sample{
 					Metric: v.Metric,
 					Point:  Point{V: v.V},
 				})
@@ -2080,7 +2080,7 @@ func (ev *evaluator) aggregation(op parser.ItemType, grouping []string, without
 			// The heap keeps the lowest value on top, so reverse it.
 			sort.Sort(sort.Reverse(aggr.reverseHeap))
 			for _, v := range aggr.reverseHeap {
-				enh.out = append(enh.out, Sample{
+				enh.Out = append(enh.Out, Sample{
 					Metric: v.Metric,
 					Point:  Point{V: v.V},
 				})
@@ -2094,12 +2094,12 @@ func (ev *evaluator) aggregation(op parser.ItemType, grouping []string, without
 			// For other aggregations, we already have the right value.
 		}
 
-		enh.out = append(enh.out, Sample{
+		enh.Out = append(enh.Out, Sample{
 			Metric: aggr.labels,
 			Point:  Point{V: aggr.value},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // btos returns 1 if b is true, 0 otherwise.

promql/functions.go

@@ -36,7 +36,7 @@ import (
 //    value,and nil for strings.
 // args are the original arguments to the function, where you can access
 //    matrixSelectors, vectorSelectors, and StringLiterals.
-// enh.out is a pre-allocated empty vector that you may use to accumulate
+// enh.Out is a pre-allocated empty vector that you may use to accumulate
 //    output before returning it. The vectors in vals should not be returned.a
 // Range vector functions need only return a vector with the right value,
 //     the metric and timestamp are not needed.
@@ -48,7 +48,7 @@ type FunctionCall func(vals []parser.Value, args parser.Expressions, enh *EvalNo
 // === time() float64 ===
 func funcTime(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
 	return Vector{Sample{Point: Point{
-		V: float64(enh.ts) / 1000,
+		V: float64(enh.Ts) / 1000,
 	}}}
 }
 
@@ -62,14 +62,14 @@ func extrapolatedRate(vals []parser.Value, args parser.Expressions, enh *EvalNod
 
 	var (
 		samples    = vals[0].(Matrix)[0]
-		rangeStart = enh.ts - durationMilliseconds(ms.Range+vs.Offset)
-		rangeEnd   = enh.ts - durationMilliseconds(vs.Offset)
+		rangeStart = enh.Ts - durationMilliseconds(ms.Range+vs.Offset)
+		rangeEnd   = enh.Ts - durationMilliseconds(vs.Offset)
 	)
 
 	// No sense in trying to compute a rate without at least two points. Drop
 	// this Vector element.
 	if len(samples.Points) < 2 {
-		return enh.out
+		return enh.Out
 	}
 	var (
 		counterCorrection float64
@@ -126,7 +126,7 @@ func extrapolatedRate(vals []parser.Value, args parser.Expressions, enh *EvalNod
 		resultValue = resultValue / ms.Range.Seconds()
 	}
 
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: resultValue},
 	})
 }
@@ -148,12 +148,12 @@ func funcIncrease(vals []parser.Value, args parser.Expressions, enh *EvalNodeHel
 
 // === irate(node parser.ValueTypeMatrix) Vector ===
 func funcIrate(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
-	return instantValue(vals, enh.out, true)
+	return instantValue(vals, enh.Out, true)
 }
 
 // === idelta(node model.ValMatrix) Vector ===
 func funcIdelta(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
-	return instantValue(vals, enh.out, false)
+	return instantValue(vals, enh.Out, false)
 }
 
 func instantValue(vals []parser.Value, out Vector, isRate bool) Vector {
@@ -234,7 +234,7 @@ func funcHoltWinters(vals []parser.Value, args parser.Expressions, enh *EvalNode
 
 	// Can't do the smoothing operation with less than two points.
 	if l < 2 {
-		return enh.out
+		return enh.Out
 	}
 
 	var s0, s1, b float64
@@ -256,7 +256,7 @@ func funcHoltWinters(vals []parser.Value, args parser.Expressions, enh *EvalNode
 		s0, s1 = s1, x+y
 	}
 
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: s1},
 	})
 }
@@ -284,12 +284,12 @@ func funcClampMax(vals []parser.Value, args parser.Expressions, enh *EvalNodeHel
 	vec := vals[0].(Vector)
 	max := vals[1].(Vector)[0].Point.V
 	for _, el := range vec {
-		enh.out = append(enh.out, Sample{
-			Metric: enh.dropMetricName(el.Metric),
+		enh.Out = append(enh.Out, Sample{
+			Metric: enh.DropMetricName(el.Metric),
 			Point:  Point{V: math.Min(max, el.V)},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // === clamp_min(Vector parser.ValueTypeVector, min Scalar) Vector ===
@@ -297,12 +297,12 @@ func funcClampMin(vals []parser.Value, args parser.Expressions, enh *EvalNodeHel
 	vec := vals[0].(Vector)
 	min := vals[1].(Vector)[0].Point.V
 	for _, el := range vec {
-		enh.out = append(enh.out, Sample{
-			Metric: enh.dropMetricName(el.Metric),
+		enh.Out = append(enh.Out, Sample{
+			Metric: enh.DropMetricName(el.Metric),
 			Point:  Point{V: math.Max(min, el.V)},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // === round(Vector parser.ValueTypeVector, toNearest=1 Scalar) Vector ===
@@ -319,23 +319,23 @@ func funcRound(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper
 
 	for _, el := range vec {
 		v := math.Floor(el.V*toNearestInverse+0.5) / toNearestInverse
-		enh.out = append(enh.out, Sample{
-			Metric: enh.dropMetricName(el.Metric),
+		enh.Out = append(enh.Out, Sample{
+			Metric: enh.DropMetricName(el.Metric),
 			Point:  Point{V: v},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // === Scalar(node parser.ValueTypeVector) Scalar ===
 func funcScalar(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
 	v := vals[0].(Vector)
 	if len(v) != 1 {
-		return append(enh.out, Sample{
+		return append(enh.Out, Sample{
 			Point: Point{V: math.NaN()},
 		})
 	}
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: v[0].V},
 	})
 }
@@ -343,7 +343,7 @@ func funcScalar(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelpe
 func aggrOverTime(vals []parser.Value, enh *EvalNodeHelper, aggrFn func([]Point) float64) Vector {
 	el := vals[0].(Matrix)[0]
 
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: aggrFn(el.Points)},
 	})
 }
@@ -431,7 +431,7 @@ func funcQuantileOverTime(vals []parser.Value, args parser.Expressions, enh *Eva
 	for _, v := range el.Points {
 		values = append(values, Sample{Point: Point{V: v.V}})
 	}
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: quantile(q, values)},
 	})
 }
@@ -467,9 +467,9 @@ func funcStdvarOverTime(vals []parser.Value, args parser.Expressions, enh *EvalN
 // === absent(Vector parser.ValueTypeVector) Vector ===
 func funcAbsent(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
 	if len(vals[0].(Vector)) > 0 {
-		return enh.out
+		return enh.Out
 	}
-	return append(enh.out,
+	return append(enh.Out,
 		Sample{
 			Metric: createLabelsForAbsentFunction(args[0]),
 			Point:  Point{V: 1},
@@ -482,7 +482,7 @@ func funcAbsent(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelpe
 // Due to engine optimization, this function is only called when this condition is true.
 // Then, the engine post-processes the results to get the expected output.
 func funcAbsentOverTime(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
-	return append(enh.out,
+	return append(enh.Out,
 		Sample{
 			Point: Point{V: 1},
 		})
@@ -490,12 +490,12 @@ func funcAbsentOverTime(vals []parser.Value, args parser.Expressions, enh *EvalN
 
 func simpleFunc(vals []parser.Value, enh *EvalNodeHelper, f func(float64) float64) Vector {
 	for _, el := range vals[0].(Vector) {
-		enh.out = append(enh.out, Sample{
-			Metric: enh.dropMetricName(el.Metric),
+		enh.Out = append(enh.Out, Sample{
+			Metric: enh.DropMetricName(el.Metric),
 			Point:  Point{V: f(el.V)},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // === abs(Vector parser.ValueTypeVector) Vector ===
@@ -542,12 +542,12 @@ func funcLog10(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper
 func funcTimestamp(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
 	vec := vals[0].(Vector)
 	for _, el := range vec {
-		enh.out = append(enh.out, Sample{
-			Metric: enh.dropMetricName(el.Metric),
+		enh.Out = append(enh.Out, Sample{
+			Metric: enh.DropMetricName(el.Metric),
 			Point:  Point{V: float64(el.T) / 1000},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // linearRegression performs a least-square linear regression analysis on the
@@ -582,14 +582,14 @@ func funcDeriv(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper
 	// No sense in trying to compute a derivative without at least two points.
 	// Drop this Vector element.
 	if len(samples.Points) < 2 {
-		return enh.out
+		return enh.Out
 	}
 
 	// We pass in an arbitrary timestamp that is near the values in use
 	// to avoid floating point accuracy issues, see
 	// https://github.com/prometheus/prometheus/issues/2674
 	slope, _ := linearRegression(samples.Points, samples.Points[0].T)
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: slope},
 	})
 }
@@ -602,11 +602,11 @@ func funcPredictLinear(vals []parser.Value, args parser.Expressions, enh *EvalNo
 	// No sense in trying to predict anything without at least two points.
 	// Drop this Vector element.
 	if len(samples.Points) < 2 {
-		return enh.out
+		return enh.Out
 	}
-	slope, intercept := linearRegression(samples.Points, enh.ts)
+	slope, intercept := linearRegression(samples.Points, enh.Ts)
 
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: slope*duration + intercept},
 	})
 }
@@ -649,14 +649,14 @@ func funcHistogramQuantile(vals []parser.Value, args parser.Expressions, enh *Ev
 
 	for _, mb := range enh.signatureToMetricWithBuckets {
 		if len(mb.buckets) > 0 {
-			enh.out = append(enh.out, Sample{
+			enh.Out = append(enh.Out, Sample{
 				Metric: mb.metric,
 				Point:  Point{V: bucketQuantile(q, mb.buckets)},
 			})
 		}
 	}
 
-	return enh.out
+	return enh.Out
 }
 
 // === resets(Matrix parser.ValueTypeMatrix) Vector ===
@@ -673,7 +673,7 @@ func funcResets(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelpe
 		prev = current
 	}
 
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: float64(resets)},
 	})
 }
@@ -692,7 +692,7 @@ func funcChanges(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelp
 		prev = current
 	}
 
-	return append(enh.out, Sample{
+	return append(enh.Out, Sample{
 		Point: Point{V: float64(changes)},
 	})
 }
@@ -716,13 +716,13 @@ func funcLabelReplace(vals []parser.Value, args parser.Expressions, enh *EvalNod
 		if !model.LabelNameRE.MatchString(dst) {
 			panic(errors.Errorf("invalid destination label name in label_replace(): %s", dst))
 		}
-		enh.dmn = make(map[uint64]labels.Labels, len(enh.out))
+		enh.Dmn = make(map[uint64]labels.Labels, len(enh.Out))
 	}
 
 	for _, el := range vector {
 		h := el.Metric.Hash()
 		var outMetric labels.Labels
-		if l, ok := enh.dmn[h]; ok {
+		if l, ok := enh.Dmn[h]; ok {
 			outMetric = l
 		} else {
 			srcVal := el.Metric.Get(src)
@@ -730,7 +730,7 @@ func funcLabelReplace(vals []parser.Value, args parser.Expressions, enh *EvalNod
 			if indexes == nil {
 				// If there is no match, no replacement should take place.
 				outMetric = el.Metric
-				enh.dmn[h] = outMetric
+				enh.Dmn[h] = outMetric
 			} else {
 				res := enh.regex.ExpandString([]byte{}, repl, srcVal, indexes)
 
@@ -739,21 +739,21 @@ func funcLabelReplace(vals []parser.Value, args parser.Expressions, enh *EvalNod
 					lb.Set(dst, string(res))
 				}
 				outMetric = lb.Labels()
-				enh.dmn[h] = outMetric
+				enh.Dmn[h] = outMetric
 			}
 		}
 
-		enh.out = append(enh.out, Sample{
+		enh.Out = append(enh.Out, Sample{
 			Metric: outMetric,
 			Point:  Point{V: el.Point.V},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // === Vector(s Scalar) Vector ===
 func funcVector(vals []parser.Value, args parser.Expressions, enh *EvalNodeHelper) Vector {
-	return append(enh.out,
+	return append(enh.Out,
 		Sample{
 			Metric: labels.Labels{},
 			Point:  Point{V: vals[0].(Vector)[0].V},
@@ -769,8 +769,8 @@ func funcLabelJoin(vals []parser.Value, args parser.Expressions, enh *EvalNodeHe
 		srcLabels = make([]string, len(args)-3)
 	)
 
-	if enh.dmn == nil {
-		enh.dmn = make(map[uint64]labels.Labels, len(enh.out))
+	if enh.Dmn == nil {
+		enh.Dmn = make(map[uint64]labels.Labels, len(enh.Out))
 	}
 
 	for i := 3; i < len(args); i++ {
@@ -789,7 +789,7 @@ func funcLabelJoin(vals []parser.Value, args parser.Expressions, enh *EvalNodeHe
 	for _, el := range vector {
 		h := el.Metric.Hash()
 		var outMetric labels.Labels
-		if l, ok := enh.dmn[h]; ok {
+		if l, ok := enh.Dmn[h]; ok {
 			outMetric = l
 		} else {
 
@@ -807,35 +807,35 @@ func funcLabelJoin(vals []parser.Value, args parser.Expressions, enh *EvalNodeHe
 			}
 
 			outMetric = lb.Labels()
-			enh.dmn[h] = outMetric
+			enh.Dmn[h] = outMetric
 		}
 
-		enh.out = append(enh.out, Sample{
+		enh.Out = append(enh.Out, Sample{
 			Metric: outMetric,
 			Point:  Point{V: el.Point.V},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // Common code for date related functions.
 func dateWrapper(vals []parser.Value, enh *EvalNodeHelper, f func(time.Time) float64) Vector {
 	if len(vals) == 0 {
-		return append(enh.out,
+		return append(enh.Out,
 			Sample{
 				Metric: labels.Labels{},
-				Point:  Point{V: f(time.Unix(enh.ts/1000, 0).UTC())},
+				Point:  Point{V: f(time.Unix(enh.Ts/1000, 0).UTC())},
 			})
 	}
 
 	for _, el := range vals[0].(Vector) {
 		t := time.Unix(int64(el.V), 0).UTC()
-		enh.out = append(enh.out, Sample{
-			Metric: enh.dropMetricName(el.Metric),
+		enh.Out = append(enh.Out, Sample{
+			Metric: enh.DropMetricName(el.Metric),
 			Point:  Point{V: f(t)},
 		})
 	}
-	return enh.out
+	return enh.Out
 }
 
 // === days_in_month(v Vector) Scalar ===