compiler: add support for the append builtin

testdata/slice.go

@@ -8,8 +8,32 @@ func main() {
 	printslice("bar", bar)
 	printslice("foo[1:2]", foo[1:2])
 	println("sum foo:", sum(foo))
+
+	// copy
 	println("copy foo -> bar:", copy(bar, foo))
 	printslice("bar", bar)
+
+	// append
+	var grow []int
+	printslice("grow", grow)
+	grow = append(grow, 42)
+	printslice("grow", grow)
+	grow = append(grow, -1, -2)
+	printslice("grow", grow)
+	grow = append(grow, foo...)
+	printslice("grow", grow)
+	grow = append(grow)
+	printslice("grow", grow)
+	grow = append(grow, grow...)
+	printslice("grow", grow)
+
+	// append string to []bytes
+	bytes := append([]byte{1, 2, 3}, "foo"...)
+	print("bytes: len=", len(bytes), " cap=", cap(bytes), " data:")
+	for _, n := range bytes {
+		print(" ", n)
+	}
+	println()
 }
 
 func printslice(name string, s []int) {

testdata/slice.txt

@@ -4,3 +4,10 @@ foo[1:2]: len=1 cap=3 data: 2
 sum foo: 12
 copy foo -> bar: 3
 bar: len=3 cap=5 data: 1 2 4
+grow: len=0 cap=0 data:
+grow: len=1 cap=1 data: 42
+grow: len=3 cap=4 data: 42 -1 -2
+grow: len=7 cap=8 data: 42 -1 -2 1 2 4 5
+grow: len=7 cap=8 data: 42 -1 -2 1 2 4 5
+grow: len=14 cap=16 data: 42 -1 -2 1 2 4 5 42 -1 -2 1 2 4 5
+bytes: len=6 cap=6 data: 1 2 3 102 111 111