Add ruby reducers

pkg/reducer/nodejs.go

@@ -10,7 +10,7 @@ import (
 )
 
 func CreateNodejs(args []string) *exec.Cmd {
-	cmd := exec.Command("node", "-e", GenerateCode(args))
+	cmd := exec.Command("node", "-e", nodejs(args))
 	cmd.Env = os.Environ()
 	cmd.Env = append(cmd.Env, "NODE_OPTIONS=--max-old-space-size=8192")
 	return cmd
@@ -19,7 +19,7 @@ func CreateNodejs(args []string) *exec.Cmd {
 //go:embed reduce.js
 var templateJs string
 
-func GenerateCodeNodejs(args []string) string {
+func nodejs(args []string) string {
 	rs := "\n"
 	for i, a := range args {
 		rs += "  try {"

pkg/reducer/python.go

@@ -7,14 +7,14 @@ import (
 )
 
 func CreatePython(bin string, args []string) *exec.Cmd {
-	cmd := exec.Command(bin, "-c", GenerateCode(args))
+	cmd := exec.Command(bin, "-c", python(args))
 	return cmd
 }
 
 //go:embed reduce.py
 var templatePython string
 
-func GenerateCodePython(args []string) string {
+func python(args []string) string {
 	rs := "\n"
 	for i, a := range args {
 		rs += "try:"
@@ -27,7 +27,7 @@ func GenerateCodePython(args []string) string {
 		default:
 			rs += fmt.Sprintf(
 				`
-    f = (lambda json: (%v))(x)
+    f = (lambda x: (%v))(x)
     x = f(x) if callable(f) else f
 `, a)
 		}

pkg/reducer/reduce.go

@@ -18,11 +18,13 @@ func GenerateCode(args []string) string {
 	if !ok {
 		lang = "node"
 	}
-	switch {
-	case lang == "node":
-		return GenerateCodeNodejs(args)
-	case strings.HasPrefix(lang, "python"):
-		return GenerateCodePython(args)
+	switch lang {
+	case "node":
+		return nodejs(args)
+	case "python", "python3":
+		return python(args)
+	case "ruby":
+		return ruby(args)
 	default:
 		panic("unknown lang")
 	}
@@ -34,11 +36,13 @@ func Reduce(object interface{}, args []string, theme Theme) {
 	if !ok {
 		lang = "node"
 	}
-	switch {
-	case lang == "node":
+	switch lang {
+	case "node":
 		cmd = CreateNodejs(args)
-	case strings.HasPrefix(lang, "python"):
+	case "python", "python3":
 		cmd = CreatePython(lang, args)
+	case "ruby":
+		cmd = CreateRuby(args)
 	default:
 		panic("unknown lang")
 	}

pkg/reducer/reduce.rb

@@ -0,0 +1,6 @@
+require 'json'
+x = JSON.parse(STDIN.read)
+
+# Reducers %v
+
+puts JSON.generate(x)

pkg/reducer/ruby.go

@@ -0,0 +1,46 @@
+package reducer
+
+import (
+	_ "embed"
+	"fmt"
+	"os/exec"
+)
+
+func CreateRuby(args []string) *exec.Cmd {
+	cmd := exec.Command("ruby", "-e", ruby(args))
+	return cmd
+}
+
+//go:embed reduce.rb
+var templateRuby string
+
+func ruby(args []string) string {
+	rs := "\n"
+	for i, a := range args {
+		rs += "begin"
+		switch {
+		case a == ".":
+			rs += `
+    x = x
+`
+
+		default:
+			rs += fmt.Sprintf(
+				`
+    x = lambda {|x| %v }.call(x)
+`, a)
+		}
+		// Generate a beautiful error message.
+		rs += "rescue Exception => e\n"
+		pre, post, pointer := trace(args, i)
+		rs += fmt.Sprintf(
+			`    STDERR.puts "\n  #{%q} #{%q} #{%q}\n  %v\n\n#{e}\n"
+    exit(1)
+`,
+			pre, a, post,
+			pointer,
+		)
+		rs += "end\n"
+	}
+	return fmt.Sprintf(templateRuby, rs)
+}