refactors to code generation

internal/cmd/avogen/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"flag"
+	"go/build"
+	"log"
+	"os"
+	"path/filepath"
+
+	"github.com/mmcloughlin/avo/internal/gen"
+	"github.com/mmcloughlin/avo/internal/load"
+)
+
+var generators = map[string]gen.Interface{
+	"asmtest": gen.NewAsmTest(),
+	"godata":  gen.NewGoData(),
+}
+
+var datadir = flag.String(
+	"data",
+	filepath.Join(build.Default.GOPATH, "src/github.com/mmcloughlin/avo/internal/data"),
+	"path to data directory",
+)
+
+var output = flag.String("output", "", "path to output file (default stdout)")
+
+func main() {
+	flag.Parse()
+
+	// Build generator.
+	t := flag.Arg(0)
+	g := generators[t]
+	if g == nil {
+		log.Fatalf("unknown generator type '%s'", t)
+	}
+
+	// Determine output writer.
+	w := os.Stdout
+	if *output != "" {
+		f, err := os.Open(*output)
+		if err != nil {
+			log.Fatal(err)
+		}
+		w = f
+	}
+
+	// Load instructions.
+	l := load.NewLoaderFromDataDir(*datadir)
+	is, err := l.Load()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Generate output.
+	b, err := g.Generate(is)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Write.
+	if _, err := w.Write(b); err != nil {
+		log.Fatal(err)
+	}
+}