Spiced up the help

* More events added, constants cleaned up
* Events now handled using noccylabs/tinyevent
* Fixed magenta/cyan mixup in style
* Fixed LineRead not resetting history pointer on command

CHANGELOG.md

@@ -0,0 +1,25 @@
+Changelog and Upgrade Instructions
+==================================
+
+## 0.2.x to 0.3.x
+
+Major changes:
+
+  * The `Shell::EV_*` constants have been renamed to `Shell::EVT_*`.
+  * The `configure` method has been removed. If you really need to
+    extend the `Shell` class, use the constructor to configure your
+    shell (see *examples/timers.php*)
+  * Events are now dispatched using the *NoccyLabs/TinyEvent* library.
+    The main difference here is in how the event object received. The
+    shell instance is now passed in the object, and you can provide any
+    userdata to be passed on to the handler when you add the listener.
+  * The event `Shell::EVT_BAD_COMMAND` will be fired if a command can
+    not be found, assuming `Context->execute()` does not accept the
+    command. (see *examples/commandevents.php*)
+
+New features:
+
+  * Tasks can now be added and removed from the shell. Tasks will receive
+    a call to their `update()` method once per main loop, until they are
+    removed or return false from the `isValid()` method. Tasks need to
+    implement the `TaskInterface` interface. (see *examples/tasks.php*)

README.md

@@ -0,0 +1,12 @@
+NoccyLabs Shell Core
+====================
+
+This library helps make elegant command line applications that spawn an isolated shell.
+It uses a standalone implementation for buffered input with support for arrow keys to
+navigate the history and more.
+
+Note that this library requirements a fully ANSI compatible terminal with UTF-8 support
+in order to use colors, control the cursor position etc. As it uses `stty` to configure
+input buffering, it will likely not work on Windows.
+
+

composer.json

@@ -13,5 +13,8 @@
         "psr-4": {
             "NoccyLabs\\Shell\\": "lib/"
         }
+    },
+    "require": {
+        "noccylabs/tinyevent": "~0.1.1"
     }
 }

examples/basic.php

@@ -0,0 +1,36 @@
+<?php
+/*
+ *  Basic shell example, demonstrates adding a listener to update the prompt with
+ *  the current time as well as creating an "anonymous" context and adding a
+ *  command to it. It also shows how to change the style of the prompt.
+ *
+ */
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Shell\Shell;
+use NoccyLabs\Shell\Style;
+use NoccyLabs\Shell\Context;
+
+$myShell = new Shell();
+
+// Set the style of prompt and input
+$myShell->setPromptStyle(new Style(Style::BR_GREEN, Style::GREEN));
+$myShell->setInputStyle(new Style(Style::BR_CYAN));
+
+// Add a listener to update the prompt
+$myShell->addListener(Shell::EVT_UPDATE_PROMPT, function ($e) {
+    $e->shell->setPrompt(date("H:i:s").">");
+});
+
+// Set the initial prompt, not really needed.
+$myShell->setPrompt("test>");
+
+// Create an anonymous context and add a command
+$ctx = $myShell->createContext("root");
+$ctx->addCommand("hello", function () {
+    echo "Hello World!\n";
+}, [ 'help'=>'Say hello' ]);
+
+// Run the shell
+$myShell->run();

examples/catchall.php

@@ -0,0 +1,20 @@
+<?php
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Shell\Shell;
+use NoccyLabs\Shell\Context;
+
+class CatchAllContext extends Context
+{
+    public function execute($cmd, ...$arg)
+    {
+        printf("Executing: %s %s\n", $cmd, join(" ",$arg));
+        return true;
+    }
+}
+
+$myShell = new Shell();
+$myShell->setPrompt("test>");
+$myShell->pushContext(new CatchAllContext());
+$myShell->run();

examples/commandevents.php

@@ -0,0 +1,44 @@
+<?php
+/*
+ *  This example demonstrates how to use events to catch commands that
+ *  have not been handled by any context or builtin.
+ *
+ */
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Shell\Shell;
+use NoccyLabs\Shell\Style;
+use NoccyLabs\Shell\Context;
+
+$myShell = new Shell();
+
+// Add a listeners for various command aspects
+$myShell->addListener(Shell::EVT_BAD_COMMAND, function ($e) {
+    echo "EVT_BAD_COMMAND:\n";
+    printf("| command: %s\n", $e->command);
+    printf("|_args: %s\n", join(" ",$e->args));
+});
+$myShell->addListener(Shell::EVT_BEFORE_COMMAND, function ($e) {
+    echo "EVT_BEFORE_COMMAND:\n";
+    printf("| command: %s\n", $e->command);
+    printf("|_args: %s\n", join(" ",$e->args));
+});
+$myShell->addListener(Shell::EVT_AFTER_COMMAND, function ($e) {
+    echo "EVT_AFTER_COMMAND:\n";
+    printf("| command: %s\n", $e->command);
+    printf("| args: %s\n", join(" ",$e->args));
+    printf("|_type: %s\n", $e->type);
+});
+
+// Set the initial prompt, not really needed.
+$myShell->setPrompt("test>");
+
+// Create an anonymous context and add a command
+$ctx = $myShell->createContext("root");
+$ctx->addCommand("hello", function () {
+    echo "Hello World!\n";
+});
+
+// Run the shell
+$myShell->run();

examples/errors.php

@@ -0,0 +1,19 @@
+<?php
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Shell\Shell;
+use NoccyLabs\Shell\Context;
+
+class CatchAllContext extends Context
+{
+    public function execute($cmd, ...$arg)
+    {
+        throw new \Exception("Uh-oh! Error!");
+    }
+}
+
+$myShell = new Shell();
+$myShell->setPrompt("test>");
+$myShell->pushContext(new CatchAllContext());
+$myShell->run();

examples/input.php

@@ -0,0 +1,31 @@
+<?php
+/*
+ *  This example demonstrates how to use events to catch commands that
+ *  have not been handled by any context or builtin.
+ *
+ */
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Shell\Shell;
+use NoccyLabs\Shell\Style;
+use NoccyLabs\Shell\Context;
+
+$myShell = new Shell();
+
+// Set the initial prompt, not really needed.
+$myShell->setPrompt("test>");
+
+// Create an anonymous context and add a command
+$ctx = $myShell->createContext("root");
+$ctx->addCommand("hello", function () use ($myShell) {
+    $myShell->getInput("What is your name?", function ($name) use ($myShell) {
+        echo "Hello, {$name}\n";
+        $myShell->getInput("Who is your daddy and what does he do?", function ($daddy) {
+            echo "{$daddy}? Oookay...\n";
+        });
+    });
+});
+
+// Run the shell
+$myShell->run();

examples/tasks.php

@@ -0,0 +1,60 @@
+<?php
+/*
+ *  This example demonstrates how to use events to catch commands that
+ *  have not been handled by any context or builtin.
+ *
+ */
+
+require_once __DIR__."/../vendor/autoload.php";
+
+use NoccyLabs\Shell\Shell;
+use NoccyLabs\Shell\Style;
+use NoccyLabs\Shell\Context;
+use NoccyLabs\Shell\TaskInterface;
+
+class MyTask implements TaskInterface
+{
+    protected $start;
+    protected $last;
+    public function __construct()
+    {
+        $this->start = time();
+    }
+    public function update()
+    {
+        if ($this->last < time()) {
+            echo date("H:i:s")."\n";
+            $this->last = time();
+        }
+    }
+    public function isValid()
+    {
+        return (time() - $this->start < 5);
+    }
+}
+
+$myShell = new Shell();
+
+$myShell->addListener(Shell::EVT_TASK_CREATED, function ($e) {
+    echo "EVT_TASK_CREATED:\n";
+    printf("|_task: %s\n", get_class($e->task));
+});
+$myShell->addListener(Shell::EVT_TASK_DESTROYED, function ($e) {
+    echo "EVT_TASK_DESTROYED:\n";
+    printf("|_task: %s\n", get_class($e->task));
+});
+
+
+$myShell->addTask(new MyTask());
+
+// Set the initial prompt, not really needed.
+$myShell->setPrompt("test>");
+
+// Create an anonymous context and add a command
+$ctx = $myShell->createContext("root");
+$ctx->addCommand("hello", function () {
+    echo "Hello World!\n";
+});
+
+// Run the shell
+$myShell->run();

examples/timers.php

@@ -24,15 +24,21 @@ class MyShell extends Shell
 
     protected $seq = 0;
 
-    protected function configure()
+    public function __construct()
     {
         $context = new MyContext();
         $this->pushContext($context);
         $this->updatePrompt();
 
-        $this->addTimer(5000, function () {
+        $t1 = $this->addTimer(5000, function () {
             echo "5 seconds\n";
         });
+        $app = $this;
+        $t2 = $this->addTimer(15000, function () use ($t1, $app) {
+            echo "Removing timers...\n";
+            $app->removeTimer($t1);
+        });
+        
     }
     
     protected function updatePrompt()

lib/Context.php

@@ -23,6 +23,11 @@ class Context
         $this->configure();
     }
 
+    public function getContextInfo()
+    {
+        return null;
+    }
+
     public function setShell(Shell $shell)
     {
         $this->shell = $shell;
@@ -141,6 +146,23 @@ class Context
         return array_key_exists('global', $info);
     }
 
+    /**
+     * Catch-all handler for commands not defined in context, globally or builtin.
+     * Override this function and return true if the command is handled ok.
+     *
+     * @param string $command The command to execute
+     * @param string[] $args The arguments to the command
+     * @return bool True if the command was handled
+     */
+    public function execute($command, ...$args)
+    {
+        return false;
+    }
+
+    /**
+     * Get the name of the context
+     *
+     */
     public function getName()
     {
         return $this->name;

lib/LineRead.php

@@ -2,6 +2,10 @@
 
 namespace NoccyLabs\Shell;
 
+/**
+ * This is a readline-like implementation in pure PHP.
+ *
+ */
 class LineRead
 {
 
@@ -127,6 +131,7 @@ class LineRead
                     array_unshift($this->history, $this->buffer);
                     $this->buffer = null;
                     $this->posCursor = 0;
+                    $this->posHistory = 0;
                     printf("\n\r");
                     $this->state = self::STATE_IDLE;
                 }
@@ -161,22 +166,33 @@ class LineRead
                 if ($this->posHistory == 0) {
                     $this->stashedBuffer = $this->buffer;
                 }
+                if ($this->posCursor == strlen($this->buffer)) {
+                    $this->posCursor = -1;
+                }
                 if ($this->posHistory < count($this->history)) {
                     $this->posHistory++;
                     $this->buffer = $this->history[$this->posHistory-1];
-                    $this->redraw();
                 }
+                if ($this->posCursor == -1) {
+                    $this->posCursor = strlen($this->buffer);
+                }
+                $this->redraw();
                 break;
             case "\e[B": // down
+                if ($this->posCursor == strlen($this->buffer)) {
+                    $this->posCursor = -1;
+                }
                 if ($this->posHistory > 1) {
                     $this->posHistory--;
                     $this->buffer = $this->history[$this->posHistory-1];
-                    $this->redraw();
                 } elseif ($this->posHistory > 0) {
                     $this->posHistory--;
                     $this->buffer = $this->stashedBuffer;
-                    $this->redraw();
                 }
+                if ($this->posCursor == -1) {
+                    $this->posCursor = strlen($this->buffer);
+                }
+                $this->redraw();
                 break;
             default:
                 fprintf(STDERR, "\n%s\n", substr($code,1));

lib/Shell.php

@@ -3,32 +3,91 @@
 namespace NoccyLabs\Shell;
 
 use NoccyLabs\Shell\LineRead;
+use NoccyLabs\TinyEvent\EventEmitterTrait;
+use NoccyLabs\TinyEvent\Event;
 
 class Shell
 {
-    const EV_PROMPT = "prompt";
-    const EV_COMMAND = "command";
+    use EventEmitterTrait;
 
+    const EVT_UPDATE_PROMPT     = "shell.prompt";   // called to update the prompt
+    const EVT_BEFORE_COMMAND    = "shell.command.before"; // before a command is executed
+    const EVT_AFTER_COMMAND     = "shell.command.after"; // after a command is executed
+    const EVT_BAD_COMMAND       = "shell.command.bad"; // no such command found
+    const EVT_CONTEXT_CHANGED   = "shell.context";  // a new context is activated
+    const EVT_SHELL_START       = "shell.start";    // the shell is about to start
+    const EVT_SHELL_STOP        = "shell.stop";     // the shell is about to exit
+    const EVT_SHELL_ABORT       = "shell.abort";    // the shell was aborted (ctrl-c)
+    const EVT_SHELL_ESCAPE      = "shell.escape";   // escape key pressed
+    const EVT_TASK_CREATED      = "task.created";   // a task was created
+    const EVT_TASK_DESTROYED    = "task.destryed";  // a task was removed or invalidated
+
+    /**
+     * @var LineRead The lineread instance
+     */
     protected $lineReader = null;
-
+    /**
+     * @var Context The current context
+     */
     protected $context = null;
-
+    /**
+     * @var Context[] The stack of parent contexts
+     */
     protected $contextStack = [];
-
-    protected $listeners = [];
-    
+    /**
+     * @var object[] Created timers
+     */ 
     protected $timers = [];
-
+    /**
+     * @var TaskInterface[] Created tasks
+     */
+    protected $tasks = [];
+    /**
+     * @var string The prompt string
+     */
     protected $prompt = ">";
+    /**
+     * @var Style The style applied to the prompt
+     */
+    protected $prompt_style = null;
+    /**
+     * @var Style The style applied to the input text
+     */
+    protected $input_style = null;
+    /**
+     * @var callable The callback to pass the input on to
+     */
+    protected $input_callback = null;
+    /**
+     * @var string Question prompt for getInput()
+     */
+    protected $input_prompt = null;
+    /**
+     * @var string The prompt before changing to $input_prompt
+     */
+    protected $input_last_prompt = null;
 
+    /**
+     * Constructor
+     *
+     */
     public function __construct()
     {
-        $this->configure();
+        $t = $this;
+        register_shutdown_function(function () use (&$t) {
+            if ($t) unset($t);
+        });
     }
 
-    protected function configure()
+    /**
+     * Destructor
+     *
+     */
+    public function __destruct()
     {
-
+        if ($this->lineReader) {
+            $this->lineReader = null;
+        }
     }
 
     /**
@@ -44,7 +103,7 @@ class Shell
         }
         $context->setShell($this);
         $this->context = $context;
-        $this->dispatchEvent("context.update", [ "context"=>$this->context ]);
+        $this->dispatchEvent(self::EVT_CONTEXT_CHANGED);
     }
 
     /**
@@ -60,7 +119,7 @@ class Shell
         } else {
             $this->context = null;
         }
-        $this->dispatchEvent("context.update", [ "context"=>$this->context ]);
+        $this->dispatchEvent(self::EVT_CONTEXT_CHANGED);
         return $previous;
     }
 
@@ -81,43 +140,19 @@ class Shell
         return join($separator,$stack);
     }
 
-    public function createContext()
+    /**
+     * Create a new empty context and push it on the stack.
+     *
+     * @param string $name The name of the context to create
+     * @return Context The created context
+     */
+    public function createContext($name)
     {
-        $context = new Context();
+        $context = new Context($name);
         $this->pushContext($context);
         return $context;
     }
 
-    /**
-     * Add a handler to be called when an event fires.
-     *
-     * @param string $event
-     * @param callable $handler
-     */ 
-    public function addListener($event, callable $handler)
-    {
-        if (!array_key_exists($event,$this->listeners)) {
-            $this->listeners[$event] = [];
-        }
-        $this->listeners[$event][] = $handler;
-    }
-
-    /**
-     * Invoke event handlers for event.
-     *
-     * @param string $event
-     * @param callable $handler
-     */
-    protected function dispatchEvent($event, array $data=[])
-    {
-        if (!array_key_exists($event,$this->listeners)) {
-            return;
-        }
-        foreach ($this->listeners[$event] as $handler) {
-            call_user_func($handler, (object)$data, $this);
-        }
-    }
-
     /**
      * Add a callback to be called at a regular interval during the update phase.
      * Adding timers with a low interval (less than 200 i.e. 0.2s) may have an
@@ -137,6 +172,7 @@ class Shell
             private $userdata;
             public function __construct($interval, callable $handler, array $userdata) {
                 $this->interval = $interval / 1000;
+                $this->next = microtime(true) + $this->interval;
                 $this->handler = $handler;
                 $this->userdata = $userdata;
             }
@@ -157,11 +193,49 @@ class Shell
      *
      * @param Timer $timer
      */
-    public function removeTimer(Timer $timer)
+    public function removeTimer($timer)
     {
-
+        $this->timers = array_filter($this->timers, function ($v) use ($timer) {
+            return ($v !== $timer);
+        });
     }
 
+    /**
+     * Add a task to be update():d in the main loop.
+     *
+     * @param TaskInterface $task The task to add
+     */
+    public function addTask(TaskInterface $task)
+    {
+        if ($this->dispatchEvent(self::EVT_TASK_CREATED, [
+            'task' => $task
+        ])->isPropagationStopped()) {
+            return;
+        }
+        $this->tasks[] = $task;
+    }
+
+    /**
+     * Remove a previously added task. This can also be done by the task returning
+     * false from its isValid() method.
+     *
+     * @param TaskInterface $task The task to remove
+     */
+    public function removeTask(TaskInterface $task)
+    {
+        $this->tasks = array_filter($this->tasks, function ($item) use ($task) {
+            return ($item != $task);
+        });
+        $this->dispatchEvent(self::EVT_TASK_DESTROYED, [
+            'task' => $task
+        ]);
+    }
+
+    /**
+     * Set the prompt text 
+     *
+     * @param string $text The text
+     */
     public function setPrompt($text)
     {
         $this->prompt = $text;
@@ -171,6 +245,34 @@ class Shell
         }
     }
 
+    /**
+     * Set the prompt style
+     *
+     * @param Style $style The style to apply to the prompt
+     */
+    public function setPromptStyle(Style $style)
+    {
+        $this->prompt_style = $style;
+
+        if ($this->lineReader) {
+            $this->lineReader->setPromptStyle($style);
+        }
+    }
+
+    /**
+     * Set the input style
+     *
+     * @param Style $style The style to apply to the text
+     */
+    public function setInputStyle(Style $style)
+    {
+        $this->input_style = $style;
+
+        if ($this->lineReader) {
+            $this->lineReader->setCommandStyle($style);
+        }
+    }
+
     /**
      * Find a command and return a closure.
      *
@@ -205,13 +307,25 @@ class Shell
      * Execute a command with arguments.
      *
      * @param string $command The command name to execute
-     * @param string $args Arguments
+     * @param string ...$args Arguments
      * @return mixed 
      * @throws Exception\BadCommandExcception
      */
     public function executeCommand($command, ...$args)
     {
+        if ($this->dispatchEvent(self::EVT_BEFORE_COMMAND, [
+            'command' => $command,
+            'args' => $args
+        ])->isPropagationStopped()) {
+            return true;
+        }
+
         if ($this->executeBuiltin($command, ...$args)) {
+            $this->dispatchEvent(self::EVT_AFTER_COMMAND, [
+                'command' => $command,
+                'args' => $args,
+                'type' => 'builtin'
+            ]);
             return;
         }
 
@@ -221,22 +335,55 @@ class Shell
             if ($ret instanceof Context) {
                 $this->pushContext($ret);
             }
+            $this->dispatchEvent(self::EVT_AFTER_COMMAND, [
+                'command' => $command,
+                'args' => $args,
+                'type' => 'command'
+            ]);
             return;
         }
+
+        // Call 'execute' on the current context
+        if ($this->context->execute($command, ...$args)) {
+            $this->dispatchEvent(self::EVT_AFTER_COMMAND, [
+                'command' => $command,
+                'args' => $args,
+                'type' => 'execute'
+            ]);
+            return;
+        }
+
+        // Fire the EVT_BAD_COMMAND event and return if the event propagation
+        // has been stopped.
+        $evt = $this->dispatchEvent(self::EVT_BAD_COMMAND, [
+            'command'=>$command,
+            'args'=>$args
+        ]);
+        if ($evt->isPropagationStopped()) {
+            return;
+        }
+
         // Throw error if the command could not be found
         throw new Exception\BadCommandException("Command {$command} not found");
     }
 
+    /**
+     * Execute a built-in command
+     *
+     * @param string $command Command name
+     * @param mixed ...$args Arguments
+     * @return bool True if the command was handled OK
+     */
     public function executeBuiltin($command, ...$args)
     {
         switch ($command) {
             case '.':
                 $type = basename(strtr(get_class($this->context), "\\", "/"));
-                printf("%s<%s>: %s\n", $type, $this->context->getName(), json_encode($this->context->getData()));
+                printf("%s<%s>: %s\n", $type, $this->context->getName(), $this->context->getContextInfo());
                 $level = 0;
                 foreach ($this->contextStack as $context) {
                     $type = basename(strtr(get_class($context), "\\", "/"));
-                    printf(" %s- %s<%s>\n", str_repeat("  ",$level++), $type, $context->getName());
+                    printf(" %s└─%s<%s>: %s\n", str_repeat("  ",$level++), $type, $context->getName(), $context->getContextInfo());
                 }
                 break;
             case '..':
@@ -260,19 +407,25 @@ class Shell
                     }
                 }
                 ksort($ghelp);
-                printf("Commands in current context:\n");
+                printf("\e[1mCommands:\e[0m\n");
                 foreach ($help as $command=>$info) {
-                    printf("  %-20s  %s\n", $command, $info);
+                    if (strpos($command," ")!==false) {
+                        list($command,$args) = explode(" ",$command,2);
+                    } else $args=null;
+                    $command = sprintf("\e[97m%s \e[90m%s\e[0m", $command,$args);
+                    printf("  %s - \e[3;36m%s\e[0m\n", $command, $info);
                 }
                 if (count($ghelp)) {
-                    printf("\nImported from parent contexts:\n");
-                    foreach ($ghelp as $command=>$info) {
-                        printf("  %-20s  %s\n", $command, $info);
-                    }
+                    printf("\n\e[0mCommands from parent contexts:\e[0m\n");
+                    if (strpos($command," ")!==false) {
+                        list($command,$args) = explode(" ",$command,2);
+                    } else $args=null;
+                    $command = sprintf("\e[97m%s \e[90m%s\e[0m", $command,$args);
+                    printf("  %s - \e[3;36m%s\e[0m\n", $command, $info);
                 }
                 printf("\nGlobal commands:\n");
-                printf("  %-20s  %s\n", "exit", "Leave the shell");
-                printf("  %-20s  %s\n", "..", "Discard the current context and go to parent");
+                printf("  \e[97m%s\e[0;36;3m - %s\e[0m\n", "exit", "Leave the shell");
+                printf("  \e[97m%s\e[0;36;3m - %s\e[0m\n", "..", "Discard the current context and go to parent");
                 break;
             case 'exit':
                 $this->stop();
@@ -299,31 +452,25 @@ class Shell
         } catch (Exception\ShellException $e) {
             echo "\e[31;91;1m{$e->getMessage()}\e[0m\n";
         }
-        /*
-        if (array_key_exists($commandName, $this->commands)) {
-            $command = $this->commands[$commandName];
-            if ($command instanceof Command) {
-                $command->run($buffer);
-            } else {
-                call_user_func_array($command,$buffer);
-            }
-            return;
-        }
-        $this->writeln("Bad command: ".$commandName);
-        */
     }
 
+    /**
+     * Start the shell
+     *
+     */
     public function run()
     {
+        try {
             $this->lineReader = new LineRead();
 
             $this->lineReader->setPromptText($this->prompt);
-        $this->lineReader->setPromptStyle(new Style(Style::BR_GREEN));
-        $this->lineReader->setCommandStyle(new Style(Style::GREEN));
+            $this->lineReader->setPromptStyle($this->prompt_style?:new Style(Style::BR_GREEN));
+            $this->lineReader->setCommandStyle($this->input_style?:new Style(Style::GREEN));
 
             $this->running = true;
 
-        $this->dispatchEvent("prompt", [ "context"=>$this->context ]);
+            $this->dispatchEvent(self::EVT_UPDATE_PROMPT);
+            $this->dispatchEvent(self::EVT_SHELL_START);
 
             while ($this->running) {
                 // Update the input stuff, sleep if nothing to do.
@@ -332,12 +479,12 @@ class Shell
                 }
                 // Escape is handy too...
                 if ($buffer == "\e") {
-                $this->dispatchEvent("shell.abort");
+                    $this->dispatchEvent(self::EVT_SHELL_ESCAPE);
                     continue;
                 }
                 // we get a ^C on ^C, so deal with the ^C.
                 if ($buffer == "\x03") {
-                $this->dispatchEvent("shell.stop");
+                    $this->dispatchEvent(self::EVT_SHELL_ABORT);
                     $this->stop();
                     continue;
                 }
@@ -347,6 +494,15 @@ class Shell
                 foreach ($this->timers as $timer) {
                     $timer->update();
                 }
+                foreach ($this->tasks as $taskidx=>$task) {
+                    $task->update();
+                    if (!$task->isValid()) {
+                        $this->dispatchEvent(self::EVT_TASK_DESTROYED, [
+                            'task' => $task
+                        ]);
+                        unset($this->tasks[$taskidx]);
+                    }
+                }
                 if ($buffer) {
                     $this->executeBuffer($buffer);
                 }
@@ -356,22 +512,73 @@ class Shell
                 if (trim($output)) {
                     $this->lineReader->erase();
                     echo rtrim($output)."\n";
+                    if ($this->running)
                         $this->lineReader->redraw();
                 }
 
                 if (!$this->context) {
                     $this->stop();
+                    break;
                 }
 
                 if ($buffer) {
-                $this->dispatchEvent("prompt", [ "context"=>$this->context ]);
+                    $this->dispatchEvent(self::EVT_UPDATE_PROMPT);
                 }
             }
 
+        } catch (\Exception $e) {
+            fprintf(STDERR, "\e[31;1mFatal: Unhandled exception\e[0m\n\n%s\n", $e);
+        }
+
+        $this->dispatchEvent(self::EVT_SHELL_STOP);
+
         $this->lineReader = null;
 
     }
+    /**
+     * Helper function to emit an event with shell instance and context included.
+     *
+     * @param string $type The event type
+     * @param array[] $data The userdata of the event
+     */
+    private function dispatchEvent($type, array $data=[])
+    {
+        $data['shell'] = $this;
+        $data['context'] = $this->context;
+        $event = new Event($type, $data);
+        $this->emitEvent($type, $event);
+        return $event;
+    }
 
+    public function getInput($prompt, callable $callback)
+    {
+        $this->addListener(Shell::EVT_UPDATE_PROMPT, [ $this, "onInputPrompt" ], $prompt);
+        $this->addListener(Shell::EVT_BEFORE_COMMAND, [ $this, "onInputHandler" ], $this->prompt, $callback);
+    }
+    
+    public function onInputPrompt(Event $e, $prompt)
+    {
+        $this->setPrompt($prompt);
+        $e->stopPropagation();
+        $this->removeListener(Shell::EVT_UPDATE_PROMPT, [ $this, "onInputPrompt" ], $prompt);
+    }
+    
+    public function onInputHandler(Event $e, $last_prompt, $callback)
+    {
+        // Restore the prompt
+        $this->setPrompt($last_prompt);
+        // Remove the listeners and compose the result string
+        $this->removeListener(Shell::EVT_BEFORE_COMMAND, [ $this, "onInputHandler" ], $last_prompt, $callback);
+        $input = trim($e->command." ".join(" ",$e->args));
+        $e->stopPropagation();
+        // Call the callback
+        call_user_func($callback, $input);
+    }
+
+    /**
+     * Stop the shell; calling this method will cause the main run() to return.
+     *
+     */
     public function stop()
     {
         $this->running = false;

lib/Style.php

@@ -11,16 +11,17 @@ class Style
     const GREEN         = 2;
     const YELLOW        = 3;
     const BLUE          = 4;
-    const CYAN          = 5;
-    const MAGENTA       = 6;
+    const MAGENTA       = 5;
+    const CYAN          = 6;
     const WHITE         = 7;
+
     const GRAY          = 8;
     const BR_RED        = 9;
     const BR_GREEN      = 10;
     const BR_YELLOW     = 11;
     const BR_BLUE       = 12;
-    const BR_CYAN       = 13;
-    const BR_MAGENTA    = 14;
+    const BR_MAGENTA    = 13;
+    const BR_CYAN       = 14;
     const BR_WHITE      = 15;
 
     const A_INTENSE     = 1;

lib/TaskInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace NoccyLabs\Shell;
+
+interface TaskInterface
+{
+    public function update();
+
+    public function isValid();
+}