mappers cat & tac

go/src/mapping/channel_mapper.go

@@ -11,10 +11,9 @@ func ChannelMapper(
 ) {
 	for {
 		lrec := <-inrecs
-		if lrec == nil {
-			outrecs <- nil
+		recordMapper.Map(lrec, outrecs)
+		if lrec == nil { // end of stream
 			break
 		}
-		recordMapper.Map(lrec, outrecs)
 	}
 }

go/src/mapping/mapper_cat.go

@@ -0,0 +1,18 @@
+package mapping
+
+import (
+	"containers"
+)
+
+type MapperCat struct {
+	// stateless
+}
+
+func NewMapperCat() *MapperCat {
+	return &MapperCat {
+	}
+}
+
+func (this *MapperCat) Map(inrec *containers.Lrec, outrecs chan<- *containers.Lrec) {
+	outrecs <- inrec
+}

go/src/mapping/mapper_tac.go

@@ -0,0 +1,30 @@
+package mapping
+
+import (
+	// System:
+	"container/list"
+	// Miller:
+	"containers"
+)
+
+type MapperTac struct {
+	lrecs *list.List
+}
+
+func NewMapperTac() *MapperTac {
+	return &MapperTac {
+		list.New(),
+	}
+}
+
+func (this *MapperTac) Map(inrec *containers.Lrec, outrecs chan<- *containers.Lrec) {
+	if inrec != nil {
+		this.lrecs.PushFront(inrec)
+	} else {
+		// end of stream
+		for e := this.lrecs.Front(); e != nil; e = e.Next() {
+			outrecs <- e.Value.(*containers.Lrec)
+		}
+		outrecs <- nil
+	}
+}

go/src/stream/stream.go

@@ -26,7 +26,9 @@ func Stream(filenames []string) error {
 	outrecs := make(chan *containers.Lrec, 1)
 	donechan := make(chan bool, 1)
 
-	recordMapper := mapping.NewMapperFoo();
+	//recordMapper := mapping.NewMapperFoo();
+	//recordMapper := mapping.NewMapperCat();
+	recordMapper := mapping.NewMapperTac();
 
 	go input.ChannelReader(reader, inrecs, echan)
 	go mapping.ChannelMapper(inrecs, recordMapper, outrecs)