added an example

examples/embedded2x/README.md

@@ -0,0 +1,22 @@
+# Parquetgen example
+
+To generate the code needed to run this example:
+
+    cd cmd/parquetgen
+    go get ./...
+    go install
+    cd ../../examples/people
+    go generate
+
+Go generate calls (see the top of main.go for the go:generate command):
+
+    //parquetgen -input main.go -type Person -package main
+
+which produces a file called parquet.go.  Now run:
+
+    go run .
+
+You should now have a parquet file that encodes a Person struct.  To
+read the values back run:
+
+    go run . -read people.parquet

examples/embedded2x/main.go

@@ -0,0 +1,72 @@
+package main
+
+//go:generate parquetgen -input main.go -type C -package main
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+)
+
+func main() {
+	f, err := os.Create("parquet")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer f.Close()
+
+	w, err := NewParquetWriter(f, MaxPageSize(2))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	w.Add(C{B: B{Name: "a", A: A{ID: 1}}})
+	w.Add(C{B: B{Name: "b", A: A{ID: 2}}})
+	w.Add(C{B: B{Name: "c", A: A{ID: 3}}})
+
+	if err := w.Write(); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := w.Close(); err != nil {
+		log.Fatal(err)
+	}
+
+	f2, err := os.Open("parquet")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f2.Close()
+
+	r, err := NewParquetReader(f2)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	enc := json.NewEncoder(os.Stdout)
+	for r.Next() {
+		var c C
+		r.Scan(&c)
+		enc.Encode(c)
+	}
+
+	if err := r.Error(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+// Being is split out only to show how embedded structs
+// are handled.
+type A struct {
+	ID int32 `parquet:"id"`
+}
+
+type B struct {
+	A
+	Name string `parquet:"name"`
+}
+
+type C struct {
+	B
+}