Module: __JS__::Opal

Defined in:
opal/opal/corelib/runtime.js.rb

Overview

This module is just a placeholder for showing the documentation of the internal JavaScript runtime. The methods you'll find defined below are actually JavaScript functions attached to the Opal global object

Class Method Summary collapse

Class Method Details

._bridgeObject

Bridges from donator to a target.


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# File 'opal/opal/corelib/runtime.js.rb', line 215

def self._bridge(*)
<<-JAVASCRIPT
   function _bridge(target, donator) {
     var id, methods, method, i, bridged;
   
     if (typeof(target) === "function") {
       id      = donator.$__id__();
       methods = donator.$instance_methods();
   
       for (i = methods.length - 1; i >= 0; i--) {
         method = '$' + methods[i];
   
         bridge_method(target, donator, method, donator.$$proto[method]);
       }
   
       if (!bridges[id]) {
         bridges[id] = [];
       }
   
       bridges[id].push(target);
     }
     else {
       bridged = bridges[target.$__id__()];
   
       if (bridged) {
         for (i = bridged.length - 1; i >= 0; i--) {
           _bridge(bridged[i], donator);
         }
   
         bridges[donator.$__id__()] = bridged.slice();
       }
     }
   }
JAVASCRIPT
end

.boot_class_allocObject

Boot a base class (makes instances).


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# File 'opal/opal/corelib/runtime.js.rb', line 253

def self.boot_class_alloc(*)
<<-JAVASCRIPT
   function boot_class_alloc(id, constructor, superklass) {
     if (superklass) {
       var alloc_proxy = function() {};
       alloc_proxy.prototype  = superklass.$$proto || superklass.prototype;
       constructor.prototype = new alloc_proxy();
     }
   
     if (id) {
       constructor.displayName = id+'_alloc';
     }
   
     constructor.prototype.constructor = constructor;
   
     return constructor;
   }
JAVASCRIPT
end

.boot_class_objectObject

The class object itself (as in Class.new)

Parameters:

  • superklass ((Opal) Class)

    Another class object (as in Class.new)

  • alloc (constructor)

    The constructor that holds the prototype that will be used for instances of the newly constructed class.


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# File 'opal/opal/corelib/runtime.js.rb', line 12

def self.boot_class_object(*)
<<-JAVASCRIPT
   function boot_class_object(id, superklass, alloc) {
     // Grab the superclass prototype and use it to build an intermediary object
     // in the prototype chain.
     function Superclass_alloc_proxy() {};
     Superclass_alloc_proxy.prototype = superklass.constructor.prototype;
     function SingletonClass_alloc() {}
     SingletonClass_alloc.prototype = new Superclass_alloc_proxy();
   
     if (id) {
       SingletonClass_alloc.displayName = "SingletonClass_alloc("+id+")";
     }
   
     // The built class is the only instance of its singleton_class
     var klass = new SingletonClass_alloc();
   
     setup_module_or_class_object(klass, SingletonClass_alloc, superklass, alloc.prototype);
   
     // @property $$alloc This is the constructor of instances of the current
     //                   class. Its prototype will be used for method lookup
     klass.$$alloc = alloc;
   
     // @property $$proto.$$class Make available to instances a reference to the
     //                           class they belong to.
     klass.$$proto.$$class = klass;
   
     return klass;
   }
JAVASCRIPT
end

.boot_core_class_objectObject

Builds the class object for core classes:

  • make the class object have a singleton class
  • make the singleton class inherit from its parent singleton class

Parameters:

  • id (String)

    the name of the class

  • alloc (Function)

    the constructor for the core class instances

  • superclass (Class alloc)

    the constructor of the superclass


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# File 'opal/opal/corelib/runtime.js.rb', line 282

def self.boot_core_class_object(*)
<<-JAVASCRIPT
   function boot_core_class_object(id, alloc, superclass) {
     var superclass_constructor = function() {};
         superclass_constructor.prototype = superclass.prototype;
   
     var singleton_class = function() {};
         singleton_class.prototype = new superclass_constructor();
   
     singleton_class.displayName = "#<Class:"+id+">";
   
     // the singleton_class acts as the class object constructor
     var klass = new singleton_class();
   
     setup_module_or_class_object(klass, singleton_class, superclass, alloc.prototype);
   
     klass.$$alloc     = alloc;
     klass.$$name      = id;
     klass.displayName = id;
   
     // Give all instances a ref to their class
     alloc.prototype.$$class = klass;
   
     Opal[id] = klass;
     Opal.constants.push(id);
   
     return klass;
   }
JAVASCRIPT
end

.boot_module_objectObject

Internal function to create a new module instance. This simply sets up the prototype hierarchy and method tables.


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# File 'opal/opal/corelib/runtime.js.rb', line 107

def self.boot_module_object(*)
<<-JAVASCRIPT
   function boot_module_object() {
     var mtor = function() {};
     mtor.prototype = Module_alloc.prototype;
   
     function module_constructor() {}
     module_constructor.prototype = new mtor();
   
     var module = new module_constructor();
     var module_prototype = {};
   
     setup_module_or_class_object(module, module_constructor, Module, module_prototype);
   
     return module;
   }
JAVASCRIPT
end

.bridge_methodObject

Bridges a single method.


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# File 'opal/opal/corelib/runtime.js.rb', line 183

def self.bridge_method(*)
<<-JAVASCRIPT
   function bridge_method(target, from, name, body) {
     var ancestors, i, ancestor, length;
   
     ancestors = target.$$bridge.$ancestors();
   
     // order important here, we have to check for method presence in
     // ancestors from the bridged class to the last ancestor
     for (i = 0, length = ancestors.length; i < length; i++) {
       ancestor = ancestors[i];
   
       if ($hasOwn.call(ancestor.$$proto, name) &&
           ancestor.$$proto[name] &&
           !ancestor.$$proto[name].$$donated &&
           !ancestor.$$proto[name].$$stub &&
           ancestor !== from) {
         break;
       }
   
       if (ancestor === from) {
         target.prototype[name] = body
         break;
       }
     }
   
   }
JAVASCRIPT
end

.build_class_singleton_classRubyClass

Build the singleton class for an existing class.

NOTE: Actually in MRI a class' singleton class inherits from its superclass' singleton class which in turn inherits from Class.

Parameters:

  • klass (RubyClass)

Returns:

  • (RubyClass)

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# File 'opal/opal/corelib/runtime.js.rb', line 135

def self.build_class_singleton_class(*)
<<-JAVASCRIPT
   function build_class_singleton_class(klass) {
     var meta = new Opal.Class.$$alloc();
   
     meta.$$class = Opal.Class;
     meta.$$proto = klass.constructor.prototype;
   
     meta.$$is_singleton = true;
     meta.$$singleton_of = klass;
     meta.$$inc          = [];
     meta.$$scope        = klass.$$scope;
   
     return klass.$$meta = meta;
   }
JAVASCRIPT
end

.build_object_singleton_classRubyClass

Build the singleton class for a Ruby (non class) Object.

Parameters:

  • object (RubyObject)

Returns:

  • (RubyClass)

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# File 'opal/opal/corelib/runtime.js.rb', line 159

def self.build_object_singleton_class(*)
<<-JAVASCRIPT
   function build_object_singleton_class(object) {
     var orig_class = object.$$class,
         class_id   = "#<Class:#<" + orig_class.$$name + ":" + orig_class.$$id + ">>";
   
     var Singleton = function() {};
     var meta = Opal.boot_class(orig_class, Singleton);
     meta.$$name   = class_id;
   
     meta.$$proto  = object;
     meta.$$class  = orig_class.$$class;
     meta.$$scope  = orig_class.$$scope;
     meta.$$parent = orig_class;
     meta.$$is_singleton = true;
     meta.$$singleton_of = object;
   
     return object.$$meta = meta;
   }
JAVASCRIPT
end

Donate methods for a module.


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# File 'opal/opal/corelib/runtime.js.rb', line 334

def self.donate(*)
<<-JAVASCRIPT
   function donate(module, jsid) {
     var included_in = module.$$dep,
         body = module.$$proto[jsid],
         i, length, includee, dest, current,
         klass_includees, j, jj, current_owner_index, module_index;
   
     if (!included_in) {
       return;
     }
   
     for (i = 0, length = included_in.length; i < length; i++) {
       includee = included_in[i];
       dest = includee.$$proto;
       current = dest[jsid];
   
       if (dest.hasOwnProperty(jsid) && !current.$$donated && !current.$$stub) {
         // target class has already defined the same method name - do nothing
       }
       else if (dest.hasOwnProperty(jsid) && !current.$$stub) {
         // target class includes another module that has defined this method
         klass_includees = includee.$$inc;
   
         for (j = 0, jj = klass_includees.length; j < jj; j++) {
           if (klass_includees[j] === current.$$donated) {
             current_owner_index = j;
           }
           if (klass_includees[j] === module) {
             module_index = j;
           }
         }
   
         // only redefine method on class if the module was included AFTER
         // the module which defined the current method body. Also make sure
         // a module can overwrite a method it defined before
         if (current_owner_index <= module_index) {
           dest[jsid] = body;
           dest[jsid].$$donated = module;
         }
       }
       else {
         // neither a class, or module included by class, has defined method
         dest[jsid] = body;
         dest[jsid].$$donated = module;
       }
   
       if (includee.$$dep) {
         donate(includee, jsid);
       }
     }
   };
JAVASCRIPT
end

When a source module is included into the target module, we must also copy its constants to the target.


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# File 'opal/opal/corelib/runtime.js.rb', line 317

def self.donate_constants(*)
<<-JAVASCRIPT
   function donate_constants(source_mod, target_mod) {
     var source_constants = source_mod.$$scope.constants,
         target_scope     = target_mod.$$scope,
         target_constants = target_scope.constants;
   
     for (var i = 0, length = source_constants.length; i < length; i++) {
       target_constants.push(source_constants[i]);
       target_scope[source_constants[i]] = source_mod.$$scope[source_constants[i]];
     }
   };
JAVASCRIPT
end

.setup_module_or_class_objectObject

Adds common/required properties to a module or class object (as in Module.new / Class.new)

Parameters:

  • module

    The module or class that needs to be prepared

  • constructor

    The constructor of the module or class itself, usually it's already assigned by using new. Some ipothesis on why it's needed can be found below.

  • superklass

    The superclass of the class/module object, for modules is Module (of Module in JS context)

  • prototype

    The prototype on which the class/module methods will be stored.


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# File 'opal/opal/corelib/runtime.js.rb', line 60

def self.setup_module_or_class_object(*)
<<-JAVASCRIPT
   function setup_module_or_class_object(module, constructor, superklass, prototype) {
     // @property $$id Each class is assigned a unique `id` that helps
     //                comparation and implementation of `#object_id`
     module.$$id = Opal.uid();
   
     // @property $$proto This is the prototype on which methods will be defined
     module.$$proto = prototype;
   
     // @property constructor keeps a ref to the constructor, but apparently the
     //                       constructor is already set on:
     //
     //                          `var module = new constructor` is called.
     //
     //                       Maybe there are some browsers not abiding (IE6?)
     module.constructor = constructor;
   
     if (superklass === Module) {
       // @property $$is_module Clearly mark this as a module
       module.$$is_module = true;
       module.$$class     = Module;
     }
     else {
       // @property $$is_class Clearly mark this as a class
       module.$$is_class = true;
       module.$$class    = Class;
     }
   
     // @property $$super the superclass, doesn't get changed by module inclusions
     module.$$super = superklass;
   
     // @property $$parent direct parent class or module
     //                    starts with the superclass, after module inclusion is
     //                    the last included module
     module.$$parent = superklass;
   
     // @property $$inc included modules
     module.$$inc = [];
   }
JAVASCRIPT
end

.stub_forObject

Generate the method_missing stub for a given method name.

Parameters:

  • method_name (String)

    The js-name of the method to stub (e.g. "$foo")


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# File 'opal/opal/corelib/runtime.js.rb', line 394

def self.stub_for(*)
<<-JAVASCRIPT
   function stub_for(method_name) {
     function method_missing_stub() {
       // Copy any given block onto the method_missing dispatcher
       this.$method_missing.$$p = method_missing_stub.$$p;
   
       // Set block property to null ready for the next call (stop false-positives)
       method_missing_stub.$$p = null;
   
       // call method missing with correct args (remove '$' prefix on method name)
       return this.$method_missing.apply(this, [method_name.slice(1)].concat($slice.call(arguments)));
     }
   
     method_missing_stub.$$stub = true;
   
     return method_missing_stub;
   }
JAVASCRIPT
end