Add socket operations

builtins/socket.go

@@ -0,0 +1,65 @@
+package builtins
+
+import (
+	"monkey/object"
+	"monkey/typing"
+	"strings"
+	"syscall"
+)
+
+// Socket ...
+func Socket(args ...object.Object) object.Object {
+	if err := typing.Check(
+		"socket", args,
+		typing.ExactArgs(1),
+		typing.WithTypes(object.STRING_OBJ),
+	); err != nil {
+		return newError(err.Error())
+	}
+
+	var (
+		domain int
+		typ    int
+		proto  int
+	)
+
+	arg := args[0].(*object.String).Value
+
+	switch strings.ToLower(arg) {
+	case "unix":
+		domain = syscall.AF_UNIX
+		typ = syscall.SOCK_STREAM
+		proto = 0
+	case "tcp4":
+		domain = syscall.AF_INET
+		typ = syscall.SOCK_STREAM
+		proto = syscall.IPPROTO_TCP
+	case "tcp6":
+		domain = syscall.AF_INET6
+		typ = syscall.SOCK_STREAM
+		proto = syscall.IPPROTO_TCP
+	case "udp4":
+		domain = syscall.AF_INET
+		typ = syscall.SOCK_DGRAM
+		proto = syscall.IPPROTO_UDP
+	case "udp6":
+		domain = syscall.AF_INET6
+		typ = syscall.SOCK_DGRAM
+		proto = syscall.IPPROTO_UDP
+	default:
+		return newError("ValueError: invalid socket type '%s'", arg)
+	}
+
+	fd, err := syscall.Socket(domain, typ, proto)
+	if err != nil {
+		return newError("SocketError: %s", err)
+	}
+
+	if domain == syscall.AF_INET || domain == syscall.AF_INET6 {
+		if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
+			return newError("SocketError: cannot enable SO_REUSEADDR: %s", err)
+		}
+	}
+
+	return &object.Integer{Value: int64(fd)}
+}