reduce allocation in funcStrip

benchmark              old ns/op     new ns/op     delta
BenchmarkFuncStrip     468           334           -28.63%

benchmark              old allocs     new allocs     delta
BenchmarkFuncStrip     1              0              -100.00%

benchmark              old bytes     new bytes     delta
BenchmarkFuncStrip     32            0             -100.00%

1 files changed, 6 insertions, 2 deletions

diff --git a/func.go b/func.go
index 37a9ea9..9dc48c1 100644
--- a/func.go
+++ b/func.go
@@ -195,9 +195,13 @@ func (f *funcStrip) Eval(w io.Writer, ev *Evaluator) {
 	abuf := newBuf()
 	f.args[1].Eval(abuf, ev)
 	ws := newWordScanner(abuf.Bytes())
-	sw := ssvWriter{w: w}
+	space := false
 	for ws.Scan() {
-		sw.Write(ws.Bytes())
+		if space {
+			writeByte(w, ' ')
+		}
+		w.Write(ws.Bytes())
+		space = true
 	}
 	freeBuf(abuf)
 }