cmd/eq: add first prototype of eq, like jq but with exprv1.7.0

Signed-off-by: Xe Iaso <me@xeiaso.net>

1 files changed, 60 insertions, 0 deletions

diff --git a/cmd/eq/main.go b/cmd/eq/main.go
new file mode 100644
index 0000000..a4bb824
--- /dev/null
+++ b/cmd/eq/main.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"io"
+	"log"
+	"os"
+
+	"github.com/antonmedv/expr"
+)
+
+var (
+	minify  = flag.Bool("minify", false, "minify JSON?")
+	noColor = flag.Bool("no-color", false, "disable color output?")
+)
+
+func main() {
+	flag.Parse()
+
+	if _, ok := os.LookupEnv("NO_COLOR"); ok {
+		*noColor = true
+	}
+
+	if flag.NArg() != 1 {
+		log.Fatal("usage: eq <expression> < data.json")
+	}
+
+	program, err := expr.Compile(flag.Arg(0))
+	if err != nil {
+		log.Fatalf("can't compile program: %v", err)
+	}
+
+	dec := json.NewDecoder(os.Stdin)
+	enc := json.NewEncoder(os.Stdout)
+
+	if !*minify {
+		enc.SetIndent("", "  ")
+	}
+
+	for {
+		obj := map[string]any{}
+		if err := dec.Decode(&obj); err != nil {
+			if err == io.EOF {
+				break
+			}
+
+			log.Fatalf("can't decode JSON: %v", err)
+		}
+
+		output, err := expr.Run(program, obj)
+		if err != nil {
+			log.Fatalf("can't run program: %v", err)
+		}
+
+		if err := enc.Encode(output); err != nil {
+			log.Fatalf("can't write JSON: %v", err)
+		}
+	}
+}