readline: migrate ansi/vt100 logic from tty to readline

The overall goal here is to make readline more interoperable with other node
Streams like say a net.Socket instance, in "terminal" mode.

See #2922 for all the details.
Closes #2922.

3 files changed, 163 insertions, 51 deletions

diff --git a/doc/api/readline.markdown b/doc/api/readline.markdown
index 66615485a21..e707a271fa3 100644
--- a/doc/api/readline.markdown
+++ b/doc/api/readline.markdown
@@ -3,7 +3,7 @@
     Stability: 3 - Stable
 
 To use this module, do `require('readline')`. Readline allows reading of a
-stream (such as STDIN) on a line-by-line basis.
+stream (such as `process.stdin`) on a line-by-line basis.
 
 Note that once you've invoked this module, your node program will not
 terminate until you've paused the interface. Here's how to allow your
@@ -11,35 +11,69 @@ program to gracefully pause:
 
     var rl = require('readline');
 
-    var i = rl.createInterface(process.stdin, process.stdout, null);
-    i.question("What do you think of node.js?", function(answer) {
+    var i = rl.createInterface({
+      input: process.stdin,
+      output: process.stdout
+    });
+
+    i.question("What do you think of node.js? ", function(answer) {
       // TODO: Log the answer in a database
-      console.log("Thank you for your valuable feedback.");
+      console.log("Thank you for your valuable feedback:", answer);
 
       i.pause();
     });
 
-## rl.createInterface(input, output, completer)
+## rl.createInterface(options)
+
+Creates a readline `Interface` instance. Accepts an "options" Object that takes
+the following values:
+
+ - `input` - the readable stream to listen to (Required).
+
+ - `output` - the writable stream to write readline data to (Required).
+
+ - `completer` - an optional function that is used for Tab autocompletion. See
+   below for an example of using this.
+
+ - `terminal` - pass `true` if the `input` and `output` streams should be treated
+   like a TTY, and have ANSI/VT100 escape codes written to it. Defaults to
+   checking `isTTY` on the `output` stream upon instantiation.
+
+The `completer` function is given a the current line entered by the user, and
+is supposed to return an Array with 2 entries:
 
-Takes two streams and creates a readline interface. The `completer` function
-is used for autocompletion. When given a substring, it returns `[[substr1,
-substr2, ...], originalsubstring]`.
+ 1. An Array with matching entries for the completion.
+
+ 2. The substring that was used for the matching.
+
+Which ends up looking something like:
+`[[substr1, substr2, ...], originalsubstring]`.
 
 Also `completer` can be run in async mode if it accepts two arguments:
 
-  function completer(linePartial, callback) {
-    callback(null, [['123'], linePartial]);
-  }
+    function completer(linePartial, callback) {
+      callback(null, [['123'], linePartial]);
+    }
 
 `createInterface` is commonly used with `process.stdin` and
 `process.stdout` in order to accept user input:
 
-    var readline = require('readline'),
-      rl = readline.createInterface(process.stdin, process.stdout);
+    var readline = require('readline');
+    var rl = readline.createInterface({
+      input: process.stdin,
+      output: process.stdout
+    });
+
+Once you have a readline instance, you most commonly listen for the `"line"` event.
+
+If `terminal` is `true` for this instance then the `output` stream will get the
+best compatability if it defines an `output.columns` property, and fires
+a `"resize"` event on the `output` if/when the columns ever change
+(`process.stdout` does this automatically when it is a TTY).
 
 ## Class: Interface
 
-The class that represents a readline interface with a stdin and stdout
+The class that represents a readline interface with an input and output
 stream.
 
 ### rl.setPrompt(prompt, length)
@@ -72,18 +106,17 @@ Example usage:
 
 ### rl.pause()
 
-Pauses the readline `in` stream, allowing it to be resumed later if needed.
+Pauses the readline `input` stream, allowing it to be resumed later if needed.
 
 ### rl.resume()
 
-Resumes the readline `in` stream.
+Resumes the readline `input` stream.
 
 ### rl.write()
 
-Writes to tty.
+Writes to `output` stream.
 
-This will also resume the `in` stream used with `createInterface` if it has
-been paused.
+This will also resume the `input` stream if it has been paused.
 
 ### Event: 'line'
 
diff --git a/doc/api/repl.markdown b/doc/api/repl.markdown
index 60a5b72ab77..c61c5751b73 100644
--- a/doc/api/repl.markdown
+++ b/doc/api/repl.markdown
@@ -1,8 +1,8 @@
 # REPL
 
-A Read-Eval-Print-Loop (REPL) is available both as a standalone program and easily
-includable in other programs.  REPL provides a way to interactively run
-JavaScript and see the results.  It can be used for debugging, testing, or
+A Read-Eval-Print-Loop (REPL) is available both as a standalone program and
+easily includable in other programs. The REPL provides a way to interactively
+run JavaScript and see the results.  It can be used for debugging, testing, or
 just trying things out.
 
 By executing `node` without any arguments from the command-line you will be
@@ -19,26 +19,39 @@ dropped into the REPL. It has simplistic emacs line-editing.
     2
     3
 
-For advanced line-editors, start node with the environmental variable `NODE_NO_READLINE=1`.
-This will start the REPL in canonical terminal settings which will allow you to use with `rlwrap`.
+For advanced line-editors, start node with the environmental variable
+`NODE_NO_READLINE=1`. This will start the main and debugger REPL in canonical
+terminal settings which will allow you to use with `rlwrap`.
 
 For example, you could add this to your bashrc file:
 
     alias node="env NODE_NO_READLINE=1 rlwrap node"
 
 
-## repl.start([prompt], [stream], [eval], [useGlobal], [ignoreUndefined])
+## repl.start(options)
 
-Returns and starts a REPL with `prompt` as the prompt and `stream` for all I/O.
-`prompt` is optional and defaults to `> `.  `stream` is optional and defaults to
-`process.stdin`. `eval` is optional too and defaults to async wrapper for
-`eval()`.
+Returns and starts a `REPLServer` instance. Accepts an "options" Object that
+takes the following values:
 
-If `useGlobal` is set to true, then the repl will use the global object,
-instead of running scripts in a separate context. Defaults to `false`.
+ - `prompt` - the prompt and `stream` for all I/O. Defaults to `> `.
 
-If `ignoreUndefined` is set to true, then the repl will not output return value
-of command if it's `undefined`. Defaults to `false`.
+ - `input` - the readable stream to listen to. Defaults to `process.stdin`.
+
+ - `output` - the writable stream to write readline data to. Defaults to
+   `process.stdout`.
+
+ - `terminal` - pass `true` if the `stream` should be treated like a TTY, and
+   have ANSI/VT100 escape codes written to it. Defaults to checking `isTTY`
+   on the `output` stream upon instantiation.
+
+ - `eval` - function that will be used to eval each given line. Defaults to
+   an async wrapper for `eval()`. See below for an example of a custom `eval`.
+
+ - `useGlobal` - if set to `true`, then the repl will use the `global` object,
+   instead of running scripts in a separate context. Defaults to `false`.
+
+ - `ignoreUndefined` - if set to `true`, then the repl will not output the
+   return value of command if it's `undefined`. Defaults to `false`.
 
 You can use your own `eval` function if it has following signature:
 
@@ -56,16 +69,32 @@ Here is an example that starts a REPL on stdin, a Unix socket, and a TCP socket:
 
     connections = 0;
 
-    repl.start("node via stdin> ");
+    repl.start({
+      prompt: "node via stdin> ",
+      input: process.stdin,
+      output: process.stdout
+    });
 
     net.createServer(function (socket) {
       connections += 1;
-      repl.start("node via Unix socket> ", socket);
+      repl.start({
+        prompt: "node via Unix socket> ",
+        input: socket,
+        output: socket
+      }).on('exit', function() {
+        socket.end();
+      })
     }).listen("/tmp/node-repl-sock");
 
     net.createServer(function (socket) {
       connections += 1;
-      repl.start("node via TCP socket> ", socket);
+      repl.start({
+        prompt: "node via TCP socket> ",
+        input: socket,
+        output: socket
+      }).on('exit', function() {
+        socket.end();
+      });
     }).listen(5001);
 
 Running this program from the command line will start a REPL on stdin.  Other
@@ -76,6 +105,12 @@ TCP sockets.
 By starting a REPL from a Unix socket-based server instead of stdin, you can
 connect to a long-running node process without restarting it.
 
+For an example of running a "full-featured" (`terminal`) REPL over
+a `net.Server` and `net.Socket` instance, see: https://gist.github.com/2209310
+
+For an example of running a REPL instance over `curl(1)`,
+see: https://gist.github.com/2053342
+
 ### Event: 'exit'
 
 `function () {}`
diff --git a/doc/api/tty.markdown b/doc/api/tty.markdown
index 21ac240ece4..54c597732bd 100644
--- a/doc/api/tty.markdown
+++ b/doc/api/tty.markdown
@@ -2,20 +2,18 @@
 
     Stability: 3 - Stable
 
-Use `require('tty')` to access this module.
-
-Example:
-
-    var tty = require('tty');
-    process.stdin.resume();
-    tty.setRawMode(true);
-    process.stdin.on('keypress', function(char, key) {
-      if (key && key.ctrl && key.name == 'c') {
-        console.log('graceful exit');
-        process.exit()
-      }
-    });
+The `tty` module houses the `tty.ReadStream` and `tty.WriteStream` classes. In
+most cases, you will not need to use this module directly.
+
+When node detects that it is being run inside a TTY context, then `process.stdin`
+will be a `tty.ReadStream` instance and `process.stdout` will be
+a `tty.WriteStream` instance. The preferred way to check if node is being run in
+a TTY context is to check `process.stdout.isTTY`:
 
+    $ node -p -e "Boolean(process.stdout.isTTY)"
+    true
+    $ node -p -e "Boolean(process.stdout.isTTY)" | cat
+    false
 
 
 ## tty.isatty(fd)
@@ -26,5 +24,51 @@ terminal.
 
 ## tty.setRawMode(mode)
 
-`mode` should be `true` or `false`. This sets the properties of the current
-process's stdin fd to act either as a raw device or default.
+Deprecated. Use `tty.ReadStream#setRawMode()` instead.
+
+
+## Class: ReadStream
+
+A `net.Socket` subclass that represents the readable portion of a tty. In normal
+circumstances, `process.stdin` will be the only `tty.ReadStream` instance in any
+node program (only when `isatty(0)` is true).
+
+### rs.isRaw
+
+A `Boolean` that is initialized to `false`. It represents the current "raw" state
+of the `tty.ReadStream` instance.
+
+### rs.setRawMode(mode)
+
+`mode` should be `true` or `false`. This sets the properties of the
+`tty.ReadStream` to act either as a raw device or default. `isRaw` will be set
+to the resulting mode.
+
+
+## Class WriteStream
+
+A `net.Socket` subclass that represents the writable portion of a tty. In normal
+circumstances, `process.stdout` will be the only `tty.WriteStream` instance
+ever created (and only when `isatty(1)` is true).
+
+### ws.columns
+
+A `Number` that gives the number of columns the TTY currently has. This property
+gets updated on "resize" events.
+
+### ws.rows
+
+A `Number` that gives the number of rows the TTY currently has. This property
+gets updated on "resize" events.
+
+### Event: 'resize'
+
+`function () {}`
+
+Emitted by `refreshSize()` when either of the `columns` or `rows` properties
+has changed.
+
+    process.stdout.on('resize', function() {
+      console.log('screen size has changed!');
+      console.log(process.stdout.columns + 'x' + process.stdout.rows);
+    });