*: mv scripts _scripts

Instead of selectively excluding this directory, hide it from the go
tooling by applying the "_" prefix.

_scripts/gen-opcodes.go

@@ -0,0 +1,95 @@
+// This script generates pkg/dwarf/op/opcodes.go from pkg/dwarf/op/opcodes.txt
+
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"go/format"
+	"log"
+	"os"
+	"strings"
+)
+
+type Opcode struct {
+	Name string
+	Code string
+	Args string
+	Func string
+}
+
+func main() {
+	fh, err := os.Open(os.Args[1])
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer fh.Close()
+
+	outfh := os.Stdout
+	if os.Args[2] != "-" {
+		outfh, err = os.Create(os.Args[2])
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer outfh.Close()
+	}
+
+	opcodes := []Opcode{}
+	s := bufio.NewScanner(fh)
+	for s.Scan() {
+		line := strings.TrimSpace(s.Text())
+		if line == "" || strings.HasPrefix(line, "//") {
+			continue
+		}
+		fields := strings.Split(line, "\t")
+		opcode := Opcode{Name: fields[0], Code: fields[1], Args: fields[2]}
+		if len(fields) > 3 {
+			opcode.Func = fields[3]
+		}
+		opcodes = append(opcodes, opcode)
+	}
+
+	var buf bytes.Buffer
+
+	fmt.Fprintf(&buf, `// THIS FILE IS AUTOGENERATED, EDIT opcodes.table INSTEAD
+	
+package op
+`)
+
+	// constants
+	fmt.Fprintf(&buf, "const (\n")
+	for _, opcode := range opcodes {
+		fmt.Fprintf(&buf, "%s Opcode = %s\n", opcode.Name, opcode.Code)
+	}
+	fmt.Fprintf(&buf, ")\n\n")
+
+	// name map
+	fmt.Fprintf(&buf, "var opcodeName = map[Opcode]string{\n")
+	for _, opcode := range opcodes {
+		fmt.Fprintf(&buf, "%s: %q,\n", opcode.Name, opcode.Name)
+	}
+	fmt.Fprintf(&buf, "}\n")
+
+	// arguments map
+	fmt.Fprintf(&buf, "var opcodeArgs = map[Opcode]string{\n")
+	for _, opcode := range opcodes {
+		fmt.Fprintf(&buf, "%s: %s,\n", opcode.Name, opcode.Args)
+	}
+	fmt.Fprintf(&buf, "}\n")
+
+	// function map
+	fmt.Fprintf(&buf, "var oplut = map[Opcode]stackfn{\n")
+	for _, opcode := range opcodes {
+		if opcode.Func != "" {
+			fmt.Fprintf(&buf, "%s: %s,\n", opcode.Name, opcode.Func)
+		}
+	}
+	fmt.Fprintf(&buf, "}\n")
+
+	src, err := format.Source(buf.Bytes())
+	if err != nil {
+		log.Fatal(err)
+	}
+	outfh.Write(src)
+}