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<h3><a href="../index.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Objects</a><ul>
<li><a class="reference internal" href="#how-to-create-your-own-object-types">How to create your own object types</a></li>
<li><a class="reference internal" href="#adding-common-functionality">Adding common functionality</a></li>
<li><a class="reference internal" href="#properties-and-functions-on-objects">Properties and functions on Objects</a></li>
<li><a class="reference internal" href="#subclasses-of-object">Subclasses of <code class="docutils literal notranslate"><span class="pre">Object</span></code></a><ul>
<li><a class="reference internal" href="#characters">Characters</a></li>
<li><a class="reference internal" href="#rooms">Rooms</a></li>
<li><a class="reference internal" href="#exits">Exits</a></li>
</ul>
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<section class="tex2jax_ignore mathjax_ignore" id="objects">
<h1>Objects<a class="headerlink" href="#objects" title="Permalink to this headline"></a></h1>
<p>All in-game objects in Evennia, be it characters, chairs, monsters, rooms or hand grenades are
represented by an Evennia <em>Object</em>. Objects form the core of Evennia and is probably what youll
spend most time working with. Objects are <a class="reference internal" href="Typeclasses.html"><span class="doc std std-doc">Typeclassed</span></a> entities.</p>
<p>An Evennia Object is, by definition, a Python class that includes
<a class="reference internal" href="../api/evennia.objects.objects.html#evennia.objects.objects.DefaultObject" title="evennia.objects.objects.DefaultObject"><span class="xref myst py py-class">evennia.objects.objects.DefaultObject</span></a> among its
parents. Evennia defines several subclasses of <code class="docutils literal notranslate"><span class="pre">DefaultObject</span></code>:</p>
<ul class="simple">
<li><p><a class="reference internal" href="../api/evennia.objects.objects.html#evennia.objects.objects.DefaultCharacter" title="evennia.objects.objects.DefaultCharacter"><span class="xref myst py py-class">evennia.objects.objects.DefaultCharacter</span></a> -
the normal in-game Character, controlled by a player.</p></li>
<li><p><a class="reference internal" href="../api/evennia.objects.objects.html#evennia.objects.objects.DefaultRoom" title="evennia.objects.objects.DefaultRoom"><span class="xref myst py py-class">evennia.objects.objects.DefaultRoom</span></a> - a location in the game world.</p></li>
<li><p><a class="reference internal" href="../api/evennia.objects.objects.html#evennia.objects.objects.DefaultExit" title="evennia.objects.objects.DefaultExit"><span class="xref myst py py-class">evennia.objects.objects.DefaultExit</span></a> - an entity that (usually) sits
in a room and represents a one-way connection to another location.</p></li>
</ul>
<p>You will usually not use the <code class="docutils literal notranslate"><span class="pre">Default*</span></code> parents themselves. In <code class="docutils literal notranslate"><span class="pre">mygame/typeclasses/</span></code> there are
convenient subclasses to use. They are empty, and thus identical to
the defaults. Tweaking them is one of the main ways to customize you game!</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">mygame.typeclasses.objects.Object</span></code> (inherits from <code class="docutils literal notranslate"><span class="pre">DefaultObject</span></code>)</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">mygame.typeclasses.characters.Character</span></code> (inherits from <code class="docutils literal notranslate"><span class="pre">DefaultCharacter</span></code>)</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">mygame.typeclasses.rooms.Room</span></code> (inherits from <code class="docutils literal notranslate"><span class="pre">DefaultRoom</span></code>)</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">mygame.typeclasses.exits.Exit</span></code> (inherits from <code class="docutils literal notranslate"><span class="pre">DefaultExit</span></code>)</p></li>
</ul>
<section id="how-to-create-your-own-object-types">
<h2>How to create your own object types<a class="headerlink" href="#how-to-create-your-own-object-types" title="Permalink to this headline"></a></h2>
<p>You can easily add your own in-game behavior by either modifying one of the typeclasses in
your game dir or by inheriting from them.</p>
<p>You can put your new typeclass directly in the relevant parent
module, or you could organize your code in some other way. Here we assume we make a new module
<code class="docutils literal notranslate"><span class="pre">mygame/typeclasses/flowers.py</span></code>:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span> <span class="c1"># mygame/typeclasses/flowers.py</span>
<span class="kn">from</span> <span class="nn">typeclasses.objects</span> <span class="kn">import</span> <span class="n">Object</span>
<span class="k">class</span> <span class="nc">Rose</span><span class="p">(</span><span class="n">Object</span><span class="p">):</span>
<span class="sd">&quot;&quot;&quot;</span>
<span class="sd"> This creates a simple rose object </span>
<span class="sd"> &quot;&quot;&quot;</span>
<span class="k">def</span> <span class="nf">at_object_creation</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="s2">&quot;this is called only once, when object is first created&quot;</span>
<span class="c1"># add a persistent attribute &#39;desc&#39; </span>
<span class="c1"># to object (silly example).</span>
<span class="bp">self</span><span class="o">.</span><span class="n">db</span><span class="o">.</span><span class="n">desc</span> <span class="o">=</span> <span class="s2">&quot;This is a pretty rose with thorns.&quot;</span>
</pre></div>
</div>
<p>Now you just need to point to the class <em>Rose</em> with the <code class="docutils literal notranslate"><span class="pre">create</span></code> command
to make a new rose:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span> @create/drop MyRose:flowers.Rose
</pre></div>
</div>
<p>What the <code class="docutils literal notranslate"><span class="pre">create</span></code> command actually <em>does</em> is to use the <a class="reference internal" href="../api/evennia.utils.create.html#evennia.utils.create.create_object" title="evennia.utils.create.create_object"><span class="xref myst py py-func">evennia.create_object</span></a>
function. You can do the same thing yourself in code:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span> <span class="kn">from</span> <span class="nn">evennia</span> <span class="kn">import</span> <span class="n">create_object</span>
<span class="n">new_rose</span> <span class="o">=</span> <span class="n">create_object</span><span class="p">(</span><span class="s2">&quot;typeclasses.flowers.Rose&quot;</span><span class="p">,</span> <span class="n">key</span><span class="o">=</span><span class="s2">&quot;MyRose&quot;</span><span class="p">)</span>
</pre></div>
</div>
<p>(The <code class="docutils literal notranslate"><span class="pre">create</span></code> command will auto-append the most likely path to your typeclass, if you enter the
call manually you have to give the full path to the class. The <code class="docutils literal notranslate"><span class="pre">create.create_object</span></code> function is
powerful and should be used for all coded object creating (so this is what you use when defining
your own building commands).</p>
<p>This particular Rose class doesnt really do much, all it does it make sure the attribute
<code class="docutils literal notranslate"><span class="pre">desc</span></code>(which is what the <code class="docutils literal notranslate"><span class="pre">look</span></code> command looks for) is pre-set, which is pretty pointless since you
will usually want to change this at build time (using the <code class="docutils literal notranslate"><span class="pre">desc</span></code> command or using the
<a class="reference internal" href="Prototypes.html"><span class="doc std std-doc">Spawner</span></a>).</p>
</section>
<section id="adding-common-functionality">
<h2>Adding common functionality<a class="headerlink" href="#adding-common-functionality" title="Permalink to this headline"></a></h2>
<p><code class="docutils literal notranslate"><span class="pre">Object</span></code>, <code class="docutils literal notranslate"><span class="pre">Character</span></code>, <code class="docutils literal notranslate"><span class="pre">Room</span></code> and <code class="docutils literal notranslate"><span class="pre">Exit</span></code> also inherit from <code class="docutils literal notranslate"><span class="pre">mygame.typeclasses.objects.ObjectParent</span></code>.
This is an empty mixin class. Optionally, you can modify this class if you want to easily add some <em>common</em> functionality to all
your Objects, Characters, Rooms and Exits at once. You can still customize each subclass separately (see the Python
docs on <a class="reference external" href="https://docs.python.org/3/tutorial/classes.html#multiple-inheritance">multiple inheritance</a> for details).</p>
<p>For example:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="c1"># in mygame/typeclasses/objects.py</span>
<span class="c1"># ... </span>
<span class="kn">from</span> <span class="nn">evennia.objects.objects</span> <span class="kn">import</span> <span class="n">DefaultObject</span>
<span class="k">class</span> <span class="nc">ObjectParent</span><span class="p">:</span>
<span class="k">def</span> <span class="nf">at_pre_get</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">getter</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="c1"># make all entities by default un-pickable</span>
<span class="k">return</span> <span class="kc">False</span>
<span class="k">class</span> <span class="nc">Object</span><span class="p">(</span><span class="n">ObjectParent</span><span class="p">,</span> <span class="n">DefaultObject</span><span class="p">):</span>
<span class="c1"># replaces at_pre_get with its own</span>
<span class="k">def</span> <span class="nf">at_pre_get</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">getter</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="k">return</span> <span class="kc">True</span>
<span class="c1"># each in their respective modules ...</span>
<span class="k">class</span> <span class="nc">Character</span><span class="p">(</span><span class="n">ObjectParent</span><span class="p">,</span> <span class="n">DefaultCharacter</span><span class="p">):</span>
<span class="c1"># will inherit at_pre_get from ObjectParent</span>
<span class="k">pass</span>
<span class="k">class</span> <span class="nc">Exit</span><span class="p">(</span><span class="n">ObjectParent</span><span class="p">,</span> <span class="n">DefaultExit</span><span class="p">):</span>
<span class="c1"># Overrides and uses the DefaultExit version of at_pre_get instead</span>
<span class="k">def</span> <span class="nf">at_pre_get</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">getter</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="k">return</span> <span class="n">DefaultExit</span><span class="o">.</span><span class="n">at_pre_get</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">getter</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
</pre></div>
</div>
</section>
<section id="properties-and-functions-on-objects">
<h2>Properties and functions on Objects<a class="headerlink" href="#properties-and-functions-on-objects" title="Permalink to this headline"></a></h2>
<p>Beyond the properties assigned to all <a class="reference internal" href="Typeclasses.html"><span class="doc std std-doc">typeclassed</span></a> objects (see that page for a list
of those), the Object also has the following custom properties:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">aliases</span></code> - a handler that allows you to add and remove aliases from this object. Use
<code class="docutils literal notranslate"><span class="pre">aliases.add()</span></code> to add a new alias and <code class="docutils literal notranslate"><span class="pre">aliases.remove()</span></code> to remove one.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">location</span></code> - a reference to the object currently containing this object.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">home</span></code> is a backup location. The main motivation is to have a safe place to move the object to if
its <code class="docutils literal notranslate"><span class="pre">location</span></code> is destroyed. All objects should usually have a home location for safety.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">destination</span></code> - this holds a reference to another object this object links to in some way. Its
main use is for <a class="reference internal" href="#exits"><span class="std std-doc">Exits</span></a>, its otherwise usually unset.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">nicks</span></code> - as opposed to aliases, a <a class="reference internal" href="Nicks.html"><span class="doc std std-doc">Nick</span></a> holds a convenient nickname replacement for a
real name, word or sequence, only valid for this object. This mainly makes sense if the Object is
used as a game character - it can then store briefer shorts, example so as to quickly reference game
commands or other characters. Use nicks.add(alias, realname) to add a new one.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">account</span></code> - this holds a reference to a connected <a class="reference internal" href="Accounts.html"><span class="doc std std-doc">Account</span></a> controlling this object (if
any). Note that this is set also if the controlling account is <em>not</em> currently online - to test if
an account is online, use the <code class="docutils literal notranslate"><span class="pre">has_account</span></code> property instead.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">sessions</span></code> - if <code class="docutils literal notranslate"><span class="pre">account</span></code> field is set <em>and the account is online</em>, this is a list of all active
sessions (server connections) to contact them through (it may be more than one if multiple
connections are allowed in settings).</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">has_account</span></code> - a shorthand for checking if an <em>online</em> account is currently connected to this
object.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">contents</span></code> - this returns a list referencing all objects inside this object (i,e. which has this
object set as their <code class="docutils literal notranslate"><span class="pre">location</span></code>).</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">exits</span></code> - this returns all objects inside this object that are <em>Exits</em>, that is, has the
<code class="docutils literal notranslate"><span class="pre">destination</span></code> property set.</p></li>
</ul>
<p>The last two properties are special:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">cmdset</span></code> - this is a handler that stores all <a class="reference internal" href="Command-Sets.html"><span class="doc std std-doc">command sets</span></a> defined on the
object (if any).</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">scripts</span></code> - this is a handler that manages <a class="reference internal" href="Scripts.html"><span class="doc std std-doc">Scripts</span></a> attached to the object (if any).</p></li>
</ul>
<p>The Object also has a host of useful utility functions. See the function headers in
<code class="docutils literal notranslate"><span class="pre">src/objects/objects.py</span></code> for their arguments and more details.</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">msg()</span></code> - this function is used to send messages from the server to an account connected to this
object.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">msg_contents()</span></code> - calls <code class="docutils literal notranslate"><span class="pre">msg</span></code> on all objects inside this object.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">search()</span></code> - this is a convenient shorthand to search for a specific object, at a given location
or globally. Its mainly useful when defining commands (in which case the object executing the
command is named <code class="docutils literal notranslate"><span class="pre">caller</span></code> and one can do <code class="docutils literal notranslate"><span class="pre">caller.search()</span></code> to find objects in the room to operate
on).</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">execute_cmd()</span></code> - Lets the object execute the given string as if it was given on the command line.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">move_to</span></code> - perform a full move of this object to a new location. This is the main move method
and will call all relevant hooks, do all checks etc.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">clear_exits()</span></code> - will delete all <a class="reference internal" href="#exits"><span class="std std-doc">Exits</span></a> to <em>and</em> from this object.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">clear_contents()</span></code> - this will not delete anything, but rather move all contents (except Exits) to
their designated <code class="docutils literal notranslate"><span class="pre">Home</span></code> locations.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">delete()</span></code> - deletes this object, first calling <code class="docutils literal notranslate"><span class="pre">clear_exits()</span></code> and
<code class="docutils literal notranslate"><span class="pre">clear_contents()</span></code>.</p></li>
</ul>
<p>The Object Typeclass defines many more <em>hook methods</em> beyond <code class="docutils literal notranslate"><span class="pre">at_object_creation</span></code>. Evennia calls
these hooks at various points. When implementing your custom objects, you will inherit from the
base parent and overload these hooks with your own custom code. See <code class="docutils literal notranslate"><span class="pre">evennia.objects.objects</span></code> for an
updated list of all the available hooks or the <a class="reference internal" href="../api/evennia.objects.objects.html#evennia.objects.objects.DefaultObject" title="evennia.objects.objects.DefaultObject"><span class="xref myst py py-class">API for DefaultObject here</span></a>.</p>
</section>
<section id="subclasses-of-object">
<h2>Subclasses of <code class="docutils literal notranslate"><span class="pre">Object</span></code><a class="headerlink" href="#subclasses-of-object" title="Permalink to this headline"></a></h2>
<p>There are three special subclasses of <em>Object</em> in default Evennia - <em>Characters</em>, <em>Rooms</em> and
<em>Exits</em>. The reason they are separated is because these particular object types are fundamental,
something you will always need and in some cases requires some extra attention in order to be
recognized by the game engine (there is nothing stopping you from redefining them though). In
practice they are all pretty similar to the base Object.</p>
<section id="characters">
<h3>Characters<a class="headerlink" href="#characters" title="Permalink to this headline"></a></h3>
<p>Characters are objects controlled by <a class="reference internal" href="Accounts.html"><span class="doc std std-doc">Accounts</span></a>. When a new Account
logs in to Evennia for the first time, a new <code class="docutils literal notranslate"><span class="pre">Character</span></code> object is created and
the Account object is assigned to the <code class="docutils literal notranslate"><span class="pre">account</span></code> attribute. A <code class="docutils literal notranslate"><span class="pre">Character</span></code> object
must have a <a class="reference internal" href="Command-Sets.html"><span class="doc std std-doc">Default Commandset</span></a> set on itself at
creation, or the account will not be able to issue any commands! If you just
inherit your own class from <code class="docutils literal notranslate"><span class="pre">evennia.DefaultCharacter</span></code> and make sure to use
<code class="docutils literal notranslate"><span class="pre">super()</span></code> to call the parent methods you should be fine. In
<code class="docutils literal notranslate"><span class="pre">mygame/typeclasses/characters.py</span></code> is an empty <code class="docutils literal notranslate"><span class="pre">Character</span></code> class ready for you
to modify.</p>
</section>
<section id="rooms">
<h3>Rooms<a class="headerlink" href="#rooms" title="Permalink to this headline"></a></h3>
<p><em>Rooms</em> are the root containers of all other objects. The only thing really separating a room from
any other object is that they have no <code class="docutils literal notranslate"><span class="pre">location</span></code> of their own and that default commands like <code class="docutils literal notranslate"><span class="pre">&#64;dig</span></code>
creates objects of this class - so if you want to expand your rooms with more functionality, just
inherit from <code class="docutils literal notranslate"><span class="pre">ev.DefaultRoom</span></code>. In <code class="docutils literal notranslate"><span class="pre">mygame/typeclasses/rooms.py</span></code> is an empty <code class="docutils literal notranslate"><span class="pre">Room</span></code> class ready for
you to modify.</p>
</section>
<section id="exits">
<h3>Exits<a class="headerlink" href="#exits" title="Permalink to this headline"></a></h3>
<p><em>Exits</em> are objects connecting other objects (usually <em>Rooms</em>) together. An object named <em>North</em> or
<em>in</em> might be an exit, as well as <em>door</em>, <em>portal</em> or <em>jump out the window</em>. An exit has two things
that separate them from other objects. Firstly, their <em>destination</em> property is set and points to a
valid object. This fact makes it easy and fast to locate exits in the database. Secondly, exits
define a special <a class="reference internal" href="Commands.html"><span class="doc std std-doc">Transit Command</span></a> on themselves when they are created. This command is
named the same as the exit object and will, when called, handle the practicalities of moving the
character to the Exitss <em>destination</em> - this allows you to just enter the name of the exit on its
own to move around, just as you would expect.</p>
<p>The exit functionality is all defined on the Exit typeclass, so you could in principle completely
change how exits work in your game (its not recommended though, unless you really know what you are
doing). Exits are <a class="reference internal" href="Locks.html"><span class="doc std std-doc">locked</span></a> using an access_type called <em>traverse</em> and also make use of a few
hook methods for giving feedback if the traversal fails. See <code class="docutils literal notranslate"><span class="pre">evennia.DefaultExit</span></code> for more info.
In <code class="docutils literal notranslate"><span class="pre">mygame/typeclasses/exits.py</span></code> there is an empty <code class="docutils literal notranslate"><span class="pre">Exit</span></code> class for you to modify.</p>
<p>The process of traversing an exit is as follows:</p>
<ol class="simple">
<li><p>The traversing <code class="docutils literal notranslate"><span class="pre">obj</span></code> sends a command that matches the Exit-command name on the Exit object. The
<a class="reference internal" href="Commands.html"><span class="doc std std-doc">cmdhandler</span></a> detects this and triggers the command defined on the Exit. Traversal always
involves the “source” (the current location) and the <code class="docutils literal notranslate"><span class="pre">destination</span></code> (this is stored on the Exit
object).</p></li>
<li><p>The Exit command checks the <code class="docutils literal notranslate"><span class="pre">traverse</span></code> lock on the Exit object</p></li>
<li><p>The Exit command triggers <code class="docutils literal notranslate"><span class="pre">at_traverse(obj,</span> <span class="pre">destination)</span></code> on the Exit object.</p></li>
<li><p>In <code class="docutils literal notranslate"><span class="pre">at_traverse</span></code>, <code class="docutils literal notranslate"><span class="pre">object.move_to(destination)</span></code> is triggered. This triggers the following hooks,
in order:</p>
<ol class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">obj.at_pre_move(destination)</span></code> - if this returns False, move is aborted.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">origin.at_pre_leave(obj,</span> <span class="pre">destination)</span></code></p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">obj.announce_move_from(destination)</span></code></p></li>
<li><p>Move is performed by changing <code class="docutils literal notranslate"><span class="pre">obj.location</span></code> from source location to <code class="docutils literal notranslate"><span class="pre">destination</span></code>.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">obj.announce_move_to(source)</span></code></p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">destination.at_object_receive(obj,</span> <span class="pre">source)</span></code></p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">obj.at_post_move(source)</span></code></p></li>
</ol>
</li>
<li><p>On the Exit object, <code class="docutils literal notranslate"><span class="pre">at_post_traverse(obj,</span> <span class="pre">source)</span></code> is triggered.</p></li>
</ol>
<p>If the move fails for whatever reason, the Exit will look for an Attribute <code class="docutils literal notranslate"><span class="pre">err_traverse</span></code> on itself
and display this as an error message. If this is not found, the Exit will instead call
<code class="docutils literal notranslate"><span class="pre">at_failed_traverse(obj)</span></code> on itself.</p>
</section>
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