JLine 3: handle `.inputrc`?

[SethTisue]

at scala/scala#8036 (comment) , @retronym wrote:

In our usage of JLine2, we picked up configuration from ~/.inputrc etc.

JLine3 does have support for parsing this file since jline/jline3@9ccfe0b, but it looks like we need to call InputRC.configure after determining which config file to use ourselves.

Furthermore, in the current configuration file, sections guarded with $if JLine .... $endif are interpreted by the Scala REPL. Under this change, config would need to be moved to $if scala (the appname used here. That's probably fine if release noted.

Here's my .inputrc for reference.

$if Bash
	"\e[A": history-search-backward
	"\e[B": history-search-forward
    Space: magic-space
$endif

#set blink-matching-paren on
"\C-xq": "\eb\"\ef\""

"\C-x)": "\ea\(\ee\)"

$if JLine
	"\C-xu": "import scala.tools.reflect.ToolBox; val m = scala.reflect.runtime.currentMirror; val u = m.universe; import u._; val tb = m.mkToolBox()"
	"\C-x)": "\C-a(\C-e)"
	"\C-x}": "\C-a{\C-e}"
	"\C-x{": "{}\C-b"
	"\C-x(": "()\C-b"

$endif

[SethTisue]

perhaps we can imitate @xuwei-k's sbt/sbt#5973

[jxnu-liguobin]

@SethTisue
I think we just need to load the file, as follows(but this test doesn't seem easy. reference resources https://github.com/sbt/sbt/pull/5973/files)

def inputrcFileUrl(): Option[URL] = {
      sys.props
         .get("jline.inputrc")
         .flatMap { path =>
           try Some(new URL(path))
           catch {
             case _: MalformedURLException =>
               Some(new File(path).toURI.toURL)
           }
         }.orElse {
        sys.props.get("user.home").map { home =>
          val f = new File(home).toPath.resolve(".inputrc").toFile
          (if (f.isFile) f else new File("/etc/inputrc")).toURI.toURL
        }
      }
    }

    def getByteArray(url: URL): Array[Byte] = {
      Using.resource(Source.fromURL(url).bufferedReader()) {
        bufferedReader =>
          LazyList.continually(bufferedReader.read).takeWhile(_ != -1).map(_.toByte).toArray
      }
    }

    lazy val inputrcFileContents: Option[Array[Byte]] = inputrcFileUrl().map(in => getByteArray(in))

    val jlineTerminal = TerminalBuilder.builder().jna(true).build()
    val completer = new Completion(completion)
    val parser    = new ReplParser(repl)
    val history   = new DefaultHistory

    val builder =
      LineReaderBuilder.builder()
      .appName("scala")
      .completer(completer)
      .history(history)
      .parser(parser)
      .terminal(jlineTerminal)

    locally {
      import LineReader._, Option._
      builder
        .option(AUTO_GROUP, false)
        .option(LIST_PACKED, true)  // TODO
        .option(INSERT_TAB, true)   // At the beginning of the line, insert tab instead of completing
        .variable(HISTORY_FILE, config.historyFile) // Save history to file
        .variable(SECONDARY_PROMPT_PATTERN, config.encolor(config.continueText)) // Continue prompt
        .variable(WORDCHARS, LineReaderImpl.DEFAULT_WORDCHARS.filterNot("*?.[]~=/&;!#%^(){}<>".toSet))
        .option(Option.DISABLE_EVENT_EXPANSION, true) // Otherwise `scala> println(raw"\n".toList)` gives `List(n)` !!
    }

    val reader = builder.build()
    try inputrcFileContents.foreach(f => InputRC.configure(reader, new ByteArrayInputStream(f))) catch {
      case NonFatal(_) =>
    } //ignore

[SethTisue]

I think manual testing on this one is fine. (And if you have access to a Windows machine to test it on, that would be cool; otherwise, we can ask for a volunteer Windows tester at PR review time.)

[jxnu-liguobin]

👌