check quad data for duplicates

seen_quad.go

package main

import (
	"compress/bzip2"
	"fmt"
	"os"

	"github.com/google/cayley/quad"
	"github.com/google/cayley/quad/nquads"
)

func main() {
	f, err := os.Open(os.Args[1])
	if err != nil {
		panic(err)
	}
	defer f.Close()

	seen := make(map[quad.Quad]struct{})
	dec := nquads.NewDecoder(bzip2.NewReader(f))
	for {
		q, err := dec.Unmarshal()
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			break
		}
		if _, exist := seen[q]; exist {
			fmt.Fprintf(os.Stderr, "already seen %#v", q)
			break
		}
		seen[q] = struct{}{}
	}
}