runtime.js
``
@note A few conventions for the documentation of this file:
- Always use "//" (in contrast with "/**/")
- The syntax used is Yardoc (yardoc.org), which is intended for Ruby (se below)
@param
and@return
types should be preceded byJS.
when referring to JavaScript constructors (e.g.JS.Function
) otherwise Ruby is assumed.nil
andnull
being unambiguous refer to the respective objects/values in Ruby and JavaScript- This is still WIP :) so please give feedback and suggestions on how to improve or for alternative solutions
The way the code is digested before going through Yardoc is a secret kept in the docs repo (https://github.com/opal/docs/tree/master).
BasicObject
The actual class for BasicObject
var BasicObject;
_Object
The actual Object class. The leading underscore is to avoid confusion with window.Object()
var _Object;
Module
The actual Module class
var Module;
Class
The actual Class class
var Class;
function: BasicObject_alloc()
Constructor for instances of BasicObject
function BasicObject_alloc(){}
function: Object_alloc()
Constructor for instances of Object
function Object_alloc(){}
function: Class_alloc()
Constructor for instances of Class
function Class_alloc(){}
function: Module_alloc()
Constructor for instances of Module
function Module_alloc(){}
function: NilClass_alloc()
Constructor for instances of NilClass (nil)
function NilClass_alloc(){}
Opal = this.Opal = {}
The Opal object that is exposed globally
var Opal = this.Opal = {};
bridges = {}
All bridged classes - keep track to donate methods from Object
var bridges = {};
TopScope = function(){}
TopScope is used for inheriting constants from the top scope
var TopScope = function(){};
TopScope.prototype = Opal
Opal just acts as the top scope
TopScope.prototype = Opal;
Opal.constructor = TopScope
To inherit scopes
Opal.constructor = TopScope;
Opal.constants = []
List top scope constants
Opal.constants = [];
Opal.global = this
This is a useful reference to global object inside ruby files
Opal.global = this;
Opal.config =
Configure runtime behavior with regards to require and unsupported fearures
Opal.config = {
$hasOwn = Opal.hasOwnProperty
Minify common function calls
var $hasOwn = Opal.hasOwnProperty;
nil_id = 4
Nil object id is always 4
var nil_id = 4;
unique_id = nil_id
Generates even sequential numbers greater than 4 (nil_id) to serve as unique ids for ruby objects
var unique_id = nil_id;
Opal.uid = function()
Return next unique id
Opal.uid = function() {
unique_id += 2;
return unique_id;
};
Opal.cvars = {}
Table holds all class variables
Opal.cvars = {};
Opal.gvars = {}
Globals table
Opal.gvars = {};
Opal.exit = function(status) { if (Opal.gvars.DEBUG) console.log('Exited with status '+status); }
Exit function, this should be replaced by platform specific implementation (See nodejs and phantom for examples)
Opal.exit = function(status) { if (Opal.gvars.DEBUG) console.log('Exited with status '+status); };
Opal.exceptions = []
keeps track of exceptions for $!
Opal.exceptions = [];
Opal.pop_exception = function()
@private
Pops an exception from the stack and updates $!
.
Opal.pop_exception = function() {
Opal.gvars["!"] = Opal.exceptions.pop() || nil;
}
``
Constants
Opal.get = function(name)
Get a constant on the given scope. Every class and module in Opal has a
scope used to store, and inherit, constants. For example, the top level
Object
in ruby has a scope accessible as Opal.Object.$$scope
.
To get the Array
class using this scope, you could use:
Opal.Object.$$scope.get("Array")
If a constant with the given name cannot be found, then a dispatch to the
class/module's #const_method
is called, which by default will raise an
error.
@param name [String] the name of the constant to lookup @return [Object]
Opal.get = function(name) {
var constant = this[name];
if (constant == null) {
return this.base.$const_get(name);
}
return constant;
};
Opal.create_scope = function(base_scope, klass, id)
Create a new constants scope for the given class with the given base. Constants are looked up through their parents, so the base scope will be the outer scope of the new klass.
@param base_scope [$$scope] the scope in which the new scope should be created @param klass [Class] @param id [String, null] the name of the newly created scope
Opal.create_scope = function(base_scope, klass, id) {
var const_alloc = function() {};
var const_scope = const_alloc.prototype = new base_scope.constructor();
klass.$$scope = const_scope;
klass.$$base_module = base_scope.base;
const_scope.base = klass;
const_scope.constructor = const_alloc;
const_scope.constants = [];
if (id) {
Opal.cdecl(base_scope, id, klass);
const_alloc.displayName = id+"_scope_alloc";
}
};
Opal.casgn = function(base_module, name, value)
Constant assignment, see also Opal.cdecl
@param base_module [Module, Class] the constant namespace @param name [String] the name of the constant @param value [Object] the value of the constant
@example Assigning a namespaced constant self::FOO = 'bar'
@example Assigning with Module#const_set Foo.const_set :BAR, 123
Opal.casgn = function(base_module, name, value) {
function update(klass, name) {
klass.$$name = name;
for (name in klass.$$scope) {
var value = klass.$$scope[name];
if (value.$$name === nil && (value.$$is_class || value.$$is_module)) {
update(value, name)
}
}
}
var scope = base_module.$$scope;
if (value.$$is_class || value.$$is_module) {
// Only checking _Object prevents setting a const on an anonymous class
// that has a superclass that's not Object
if (value.$$is_class || value.$$base_module === _Object) {
value.$$base_module = base_module;
}
if (value.$$name === nil && value.$$base_module.$$name !== nil) {
update(value, name);
}
}
scope.constants.push(name);
scope[name] = value;
// If we dynamically declare a constant in a module,
// we should populate all the classes that include this module
// with the same constant
if (base_module.$$is_module && base_module.$$dep) {
for (var i = 0; i < base_module.$$dep.length; i++) {
var dep = base_module.$$dep[i];
Opal.casgn(dep, name, value);
}
}
return value;
};
Opal.cdecl = function(base_scope, name, value)
Constant declaration
@example FOO = :bar
@param base_scope [$$scope] the current scope @param name [String] the name of the constant @param value [Object] the value of the constant
Opal.cdecl = function(base_scope, name, value) {
if ((value.$$is_class || value.$$is_module) && value.$$orig_scope == null) {
value.$$name = name;
value.$$orig_scope = base_scope;
// Here we should explicitly set a base module
// (a module where the constant was initially defined)
value.$$base_module = base_scope.base;
base_scope.constructor[name] = value;
}
base_scope.constants.push(name);
return base_scope[name] = value;
};
``
Modules & Classes
Opal.klass = function(base, superclass, name, constructor)
A class Foo; end
expression in ruby is compiled to call this runtime
method which either returns an existing class of the given name, or creates
a new class in the given base
scope.
If a constant with the given name exists, then we check to make sure that
it is a class and also that the superclasses match. If either of these
fail, then we raise a TypeError
. Note, superclass
may be null if one
was not specified in the ruby code.
We pass a constructor to this method of the form function ClassName() {}
simply so that classes show up with nicely formatted names inside debuggers
in the web browser (or node/sprockets).
The base
is the current self
value where the class is being created
from. We use this to get the scope for where the class should be created.
If base
is an object (not a class/module), we simple get its class and
use that as the base instead.
@param base [Object] where the class is being created @param superclass [Class,null] superclass of the new class (may be null) @param id [String] the name of the class to be created @param constructor [JS.Function] function to use as constructor
@return new [Class] or existing ruby class
Opal.klass = function(base, superclass, name, constructor) {
var klass, bridged, alloc;
// If base is an object, use its class
if (!base.$$is_class && !base.$$is_module) {
base = base.$$class;
}
// If the superclass is a function then we're bridging a native JS class
if (typeof(superclass) === 'function') {
bridged = superclass;
superclass = _Object;
}
// Try to find the class in the current scope
klass = base.$$scope[name];
// If the class exists in the scope, then we must use that
if (klass && klass.$$orig_scope === base.$$scope) {
// Make sure the existing constant is a class, or raise error
if (!klass.$$is_class) {
throw Opal.TypeError.$new(name + " is not a class");
}
// Make sure existing class has same superclass
if (superclass && klass.$$super !== superclass) {
throw Opal.TypeError.$new("superclass mismatch for class " + name);
}
return klass;
}
// Class doesnt exist, create a new one with given superclass...
// Not specifying a superclass means we can assume it to be Object
if (superclass == null) {
superclass = _Object;
}
// If bridged the JS class will also be the alloc function
alloc = bridged || Opal.boot_class_alloc(name, constructor, superclass);
// Create the class object (instance of Class)
klass = Opal.setup_class_object(name, alloc, superclass.$$name, superclass.constructor);
// @property $$super the superclass, doesn't get changed by module inclusions
klass.$$super = superclass;
// @property $$parent direct parent class
// starts with the superclass, after klass inclusion is
// the last included klass
klass.$$parent = superclass;
// Every class gets its own constant scope, inherited from current scope
Opal.create_scope(base.$$scope, klass, name);
// Name new class directly onto current scope (Opal.Foo.Baz = klass)
base[name] = klass;
if (bridged) {
Opal.bridge(klass, alloc);
}
else {
// Copy all parent constants to child, unless parent is Object
if (superclass !== _Object && superclass !== BasicObject) {
Opal.donate_constants(superclass, klass);
}
// Call .inherited() hook with new class on the superclass
if (superclass.$inherited) {
superclass.$inherited(klass);
}
}
return klass;
};
Opal.boot_class_alloc = function(name, constructor, superclass)
Boot a base class (makes instances).
@param name [String,null] the class name @param constructor [JS.Function] the class' instances constructor/alloc function @param superclass [Class,null] the superclass object @return [JS.Function] the consturctor holding the prototype for the class' instances
Opal.boot_class_alloc = function(name, constructor, superclass) {
if (superclass) {
var alloc_proxy = function() {};
alloc_proxy.prototype = superclass.$$proto || superclass.prototype;
constructor.prototype = new alloc_proxy();
}
if (name) {
constructor.displayName = name+'_alloc';
}
constructor.prototype.constructor = constructor;
return constructor;
};
Opal.setup_class_object = function(name, alloc, superclass_name, superclass_alloc)
Adds common/required properties to class object (as in Class.new
)
@param name [String,null] The name of the class
@param alloc [JS.Function] The constructor of the class' instances
@param superclass_name [String,null]
The name of the super class, this is
usefule to build the .displayName
of the singleton class
@param superclass_alloc [JS.Function] The constructor of the superclass from which the singleton_class is derived.
@return [Class]
Opal.setup_class_object = function(name, alloc, superclass_name, superclass_alloc) {
// Grab the superclass prototype and use it to build an intermediary object
// in the prototype chain.
var superclass_alloc_proxy = function() {};
superclass_alloc_proxy.prototype = superclass_alloc.prototype;
superclass_alloc_proxy.displayName = superclass_name;
var singleton_class_alloc = function() {}
singleton_class_alloc.prototype = new superclass_alloc_proxy();
// The built class is the only instance of its singleton_class
var klass = new singleton_class_alloc();
// @property $$alloc This is the constructor of instances of the current
// class. Its prototype will be used for method lookup
klass.$$alloc = alloc;
klass.$$name = name || nil;
// @property $$id Each class is assigned a unique `id` that helps
// comparation and implementation of `#object_id`
klass.$$id = Opal.uid();
// Set a displayName for the singleton_class
singleton_class_alloc.displayName = "#<Class:"+(name || ("#<Class:"+klass.$$id+">"))+">";
// @property $$proto This is the prototype on which methods will be defined
klass.$$proto = alloc.prototype;
// @property $$proto.$$class Make available to instances a reference to the
// class they belong to.
klass.$$proto.$$class = klass;
// @property constructor keeps a ref to the constructor, but apparently the
// constructor is already set on:
//
// `var klass = new constructor` is called.
//
// Maybe there are some browsers not abiding (IE6?)
klass.constructor = singleton_class_alloc;
// @property $$is_class Clearly mark this as a class
klass.$$is_class = true;
// @property $$class Classes are instances of the class Class
klass.$$class = Class;
// @property $$inc included modules
klass.$$inc = [];
return klass;
};
Opal.module = function(base, name)
Define new module (or return existing module). The given base
is basically
the current self
value the module
statement was defined in. If this is
a ruby module or class, then it is used, otherwise if the base is a ruby
object then that objects real ruby class is used (e.g. if the base is the
main object, then the top level Object
class is used as the base).
If a module of the given name is already defined in the base, then that instance is just returned.
If there is a class of the given name in the base, then an error is generated instead (cannot have a class and module of same name in same base).
Otherwise, a new module is created in the base with the given name, and that new instance is returned back (to be referenced at runtime).
@param base [Module, Class] class or module this definition is inside @param id [String] the name of the new (or existing) module
@return [Module]
Opal.module = function(base, name) {
var module;
if (!base.$$is_class && !base.$$is_module) {
base = base.$$class;
}
if ($hasOwn.call(base.$$scope, name)) {
module = base.$$scope[name];
if (!module.$$is_module && module !== _Object) {
throw Opal.TypeError.$new(name + " is not a module");
}
}
else {
module = Opal.module_allocate();
Opal.create_scope(base.$$scope, module, name);
}
return module;
};
Opal.module_initialize = function(module, block)
The implementation for Module#initialize @param module [Module] @param block [Proc,nil] @return nil
Opal.module_initialize = function(module, block) {
if (block !== nil) {
var block_self = block.$$s;
block.$$s = null;
block.call(module);
block.$$s = block_self;
}
return nil;
};
Opal.module_allocate = function()
Internal function to create a new module instance. This simply sets up the prototype hierarchy and method tables.
Opal.module_allocate = function() {
var mtor = function() {};
mtor.prototype = Module_alloc.prototype;
function module_constructor() {}
module_constructor.prototype = new mtor();
var module = new module_constructor();
var module_prototype = {};
var superclass = Module;
// @property $$id Each class is assigned a unique `id` that helps
// comparation and implementation of `#object_id`
module.$$id = Opal.uid();
// Set the display name of the singleton prototype holder
module_constructor.displayName = "#<Class:#<Module:"+module.$$id+">>"
// @property $$proto This is the prototype on which methods will be defined
module.$$proto = module_prototype;
// @property constructor
// keeps a ref to the constructor, but apparently the
// constructor is already set on:
//
// `var module = new constructor` is called.
//
// Maybe there are some browsers not abiding (IE6?)
module.constructor = module_constructor;
// @property $$is_module Clearly mark this as a module
module.$$is_module = true;
module.$$class = Module;
// @property $$super
// the superclass, doesn't get changed by module inclusions
module.$$super = superclass;
// @property $$parent
// direct parent class or module
// starts with the superclass, after module inclusion is
// the last included module
module.$$parent = superclass;
// @property $$inc included modules
module.$$inc = [];
// mark the object as a module
module.$$is_module = true;
// initialize dependency tracking
module.$$dep = [];
// initialize the name with nil
module.$$name = nil;
return module;
};
Opal.get_singleton_class = function(object)
Return the singleton class for the passed object.
If the given object alredy has a singleton class, then it will be stored on
the object as the $$meta
property. If this exists, then it is simply
returned back.
Otherwise, a new singleton object for the class or object is created, set on
the object at $$meta
for future use, and then returned.
@param object [Object] the ruby object @return [Class] the singleton class for object
Opal.get_singleton_class = function(object) {
if (object.$$meta) {
return object.$$meta;
}
if (object.$$is_class || object.$$is_module) {
return Opal.build_class_singleton_class(object);
}
return Opal.build_object_singleton_class(object);
};
Opal.build_class_singleton_class = function(object)
Build the singleton class for an existing class. Class object are built
with their singleton class already in the prototype chain and inheriting
from their superclass object (up to Class
itself).
NOTE: Actually in MRI a class' singleton class inherits from its superclass' singleton class which in turn inherits from Class.
@param klass [Class] @return [Class]
Opal.build_class_singleton_class = function(object) {
var alloc, superclass, klass;
if (object.$$meta) {
return object.$$meta;
}
// The constructor and prototype of the singleton_class instances is the
// current class constructor and prototype.
alloc = object.constructor;
// The singleton_class superclass is the singleton_class of its superclass;
// but BasicObject has no superclass (its `$$super` is null), thus we
// fallback on `Class`.
superclass = object === BasicObject ? Class : Opal.build_class_singleton_class(object.$$super);
klass = Opal.setup_class_object(null, alloc, superclass.$$name, superclass.constructor);
klass.$$super = superclass;
klass.$$parent = superclass;
// The singleton_class retains the same scope as the original class
Opal.create_scope(object.$$scope, klass);
klass.$$is_singleton = true;
klass.$$singleton_of = object;
return object.$$meta = klass;
};
Opal.build_object_singleton_class = function(object)
Build the singleton class for a Ruby (non class) Object.
@param object [Object] @return [Class]
Opal.build_object_singleton_class = function(object) {
var superclass = object.$$class,
name = "#<Class:#<" + superclass.$$name + ":" + superclass.$$id + ">>";
var alloc = Opal.boot_class_alloc(name, function(){}, superclass)
var klass = Opal.setup_class_object(name, alloc, superclass.$$name, superclass.constructor);
klass.$$super = superclass;
klass.$$parent = superclass;
klass.$$class = superclass.$$class;
klass.$$scope = superclass.$$scope;
klass.$$proto = object;
klass.$$is_singleton = true;
klass.$$singleton_of = object;
return object.$$meta = klass;
};
Opal.bridge_method = function(target, from, name, body)
Bridges a single method.
Opal.bridge_method = function(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].$$stub &&
ancestor !== from) {
break;
}
if (ancestor === from) {
target.prototype[name] = body
break;
}
}
};
Opal._bridge = function(target, donator)
Bridges from donator to a target.
Opal._bridge = function(target, donator) {
var id, methods, method, i, bridged;
if (typeof(target) === "function") {
id = donator.$__id__();
methods = donator.$instance_methods();
for (i = methods.length - 1; i >= 0; i--) {
method = '$' + methods[i];
Opal.bridge_method(target, donator, method, donator.$$proto[method]);
}
if (!bridges[id]) {
bridges[id] = [];
}
bridges[id].push(target);
}
else {
bridged = bridges[target.$__id__()];
if (bridged) {
for (i = bridged.length - 1; i >= 0; i--) {
Opal._bridge(bridged[i], donator);
}
bridges[donator.$__id__()] = bridged.slice();
}
}
};
Opal.append_features = function(module, klass)
The actual inclusion of a module into a class.
Class $$parent
and iclass
To handle super
calls, every class has a $$parent
. This parent is
used to resolve the next class for a super call. A normal class would
have this point to its superclass. However, if a class includes a module
then this would need to take into account the module. The module would
also have to then point its $$parent
to the actual superclass. We
cannot modify modules like this, because it might be included in more
then one class. To fix this, we actually insert an iclass
as the class'
$$parent
which can then point to the superclass. The iclass
acts as
a proxy to the actual module, so the super
chain can then search it for
the required method.
@param module [Module] the module to include @param klass [Class] the target class to include module into @return [null]
Opal.append_features = function(module, klass) {
var iclass, donator, prototype, methods, id, i;
// check if this module is already included in the class
for (i = klass.$$inc.length - 1; i >= 0; i--) {
if (klass.$$inc[i] === module) {
return;
}
}
klass.$$inc.push(module);
module.$$dep.push(klass);
Opal._bridge(klass, module);
// iclass
iclass = {
$$name: module.$$name,
$$proto: module.$$proto,
$$parent: klass.$$parent,
$$module: module,
$$iclass: true
};
klass.$$parent = iclass;
donator = module.$$proto;
prototype = klass.$$proto;
methods = module.$instance_methods();
for (i = methods.length - 1; i >= 0; i--) {
id = '$' + methods[i];
// if the target class already has a method of the same name defined
// and that method was NOT donated, then it must be a method defined
// by the class so we do not want to override it
if ( prototype.hasOwnProperty(id) &&
!prototype[id].$$donated &&
!prototype[id].$$stub) {
continue;
}
prototype[id] = donator[id];
prototype[id].$$donated = module;
}
Opal.donate_constants(module, klass);
};
Opal.stubs = {}
Table that holds all methods that have been defined on all objects It is used for defining method stubs for new coming native classes
Opal.stubs = {};
Opal.bridge = function(klass, constructor)
For performance, some core Ruby classes are toll-free bridged to their native JavaScript counterparts (e.g. a Ruby Array is a JavaScript Array).
This method is used to setup a native constructor (e.g. Array), to have its prototype act like a normal Ruby class. Firstly, a new Ruby class is created using the native constructor so that its prototype is set as the target for th new class. Note: all bridged classes are set to inherit from Object.
Example:
Opal.bridge(self, Function);
@param klass [Class] the Ruby class to bridge @param constructor [JS.Function] native JavaScript constructor to use @return [Class] returns the passed Ruby class
Opal.bridge = function(klass, constructor) {
if (constructor.$$bridge) {
throw Opal.ArgumentError.$new("already bridged");
}
Opal.stub_subscribers.push(constructor.prototype);
// Populate constructor with previously stored stubs
for (var method_name in Opal.stubs) {
if (!(method_name in constructor.prototype)) {
constructor.prototype[method_name] = Opal.stub_for(method_name);
}
}
constructor.prototype.$$class = klass;
constructor.$$bridge = klass;
var ancestors = klass.$ancestors();
// order important here, we have to bridge from the last ancestor to the
// bridged class
for (var i = ancestors.length - 1; i >= 0; i--) {
Opal._bridge(constructor, ancestors[i]);
}
for (var name in BasicObject_alloc.prototype) {
var method = BasicObject_alloc.prototype[method];
if (method && method.$$stub && !(name in constructor.prototype)) {
constructor.prototype[name] = method;
}
}
return klass;
};
Opal.donate_constants = function(source_mod, target_mod)
When a source module is included into the target module, we must also copy its constants to the target.
Opal.donate_constants = function(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.$$scope[source_constants[i]];
}
};
Opal.donate = function(module, jsid)
Donate methods for a module.
Opal.donate = function(module, jsid) {
var included_in = module.$$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) {
Opal.donate(includee, jsid);
}
}
};
Opal.ancestors = function(module_or_class)
The Array of ancestors for a given module/class
Opal.ancestors = function(module_or_class) {
var parent = module_or_class,
result = [],
modules;
while (parent) {
result.push(parent);
for (var i=0; i < parent.$$inc.length; i++) {
modules = Opal.ancestors(parent.$$inc[i]);
for(var j = 0; j < modules.length; j++) {
result.push(modules[j]);
}
}
// only the actual singleton class gets included in its ancestry
// after that, traverse the normal class hierarchy
if (parent.$$is_singleton && parent.$$singleton_of.$$is_module) {
parent = parent.$$singleton_of.$$super;
}
else {
parent = parent.$$is_class ? parent.$$super : null;
}
}
return result;
};
``
Method Missing
Opal.add_stubs = function(stubs)
Methods stubs are used to facilitate method_missing in opal. A stub is a
placeholder function which just calls method_missing
on the receiver.
If no method with the given name is actually defined on an object, then it
is obvious to say that the stub will be called instead, and then in turn
method_missing will be called.
When a file in ruby gets compiled to javascript, it includes a call to this function which adds stubs for every method name in the compiled file. It should then be safe to assume that method_missing will work for any method call detected.
Method stubs are added to the BasicObject prototype, which every other ruby object inherits, so all objects should handle method missing. A stub is only added if the given property name (method name) is not already defined.
Note: all ruby methods have a $
prefix in javascript, so all stubs will
have this prefix as well (to make this method more performant).
Opal.add_stubs(["$foo", "$bar", "$baz="]);
All stub functions will have a private $$stub
property set to true so
that other internal methods can detect if a method is just a stub or not.
Kernel#respond_to?
uses this property to detect a methods presence.
@param stubs [Array] an array of method stubs to add @return [undefined]
Opal.add_stubs = function(stubs) {
var subscriber, subscribers = Opal.stub_subscribers,
i, ilength = stubs.length,
j, jlength = subscribers.length,
method_name, stub;
for (i = 0; i < ilength; i++) {
method_name = stubs[i];
// Save method name to populate other subscribers with this stub
Opal.stubs[method_name] = true;
stub = Opal.stub_for(method_name);
for (j = 0; j < jlength; j++) {
subscriber = subscribers[j];
if (!(method_name in subscriber)) {
subscriber[method_name] = stub;
}
}
}
};
Opal.stub_subscribers = [BasicObject_alloc.prototype]
Keep a list of prototypes that want method_missing stubs to be added.
@default [Prototype List] BasicObject_alloc.prototype
Opal.stub_subscribers = [BasicObject_alloc.prototype];
Opal.add_stub_for = function(prototype, stub)
Add a method_missing stub function to the given prototype for the given name.
@param prototype [Prototype] the target prototype @param stub [String] stub name to add (e.g. "$foo") @return [undefined]
Opal.add_stub_for = function(prototype, stub) {
var method_missing_stub = Opal.stub_for(stub);
prototype[stub] = method_missing_stub;
};
Opal.stub_for = function(method_name)
Generate the method_missing stub for a given method name.
@param method_name [String] The js-name of the method to stub (e.g. "$foo") @return [undefined]
Opal.stub_for = function(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.$$p = null;
// call method missing with correct args (remove '$' prefix on method name)
var args_ary = new Array(arguments.length);
for(var i = 0, l = args_ary.length; i < l; i++) { args_ary[i] = arguments[i]; }
return this.$method_missing.apply(this, [method_name.slice(1)].concat(args_ary));
}
method_missing_stub.$$stub = true;
return method_missing_stub;
};
``
Methods
Opal.ac = function(actual, expected, object, meth)
Arity count error dispatcher for methods
@param actual [Fixnum] number of arguments given to method @param expected [Fixnum] expected number of arguments @param object [Object] owner of the method +meth+ @param meth [String] method name that got wrong number of arguments @raise [ArgumentError]
Opal.ac = function(actual, expected, object, meth) {
var inspect = '';
if (object.$$is_class || object.$$is_module) {
inspect += object.$$name + '.';
}
else {
inspect += object.$$class.$$name + '#';
}
inspect += meth;
throw Opal.ArgumentError.$new('[' + inspect + '] wrong number of arguments(' + actual + ' for ' + expected + ')');
};
Opal.block_ac = function(actual, expected, context)
Arity count error dispatcher for blocks
@param actual [Fixnum] number of arguments given to block @param expected [Fixnum] expected number of arguments @param context [Object] context of the block definition @raise [ArgumentError]
Opal.block_ac = function(actual, expected, context) {
var inspect = "`block in " + context + "'";
throw Opal.ArgumentError.$new(inspect + ': wrong number of arguments (' + actual + ' for ' + expected + ')');
}
Opal.find_super_dispatcher = function(obj, jsid, current_func, defcheck, defs)
Super dispatcher
Opal.find_super_dispatcher = function(obj, jsid, current_func, defcheck, defs) {
var dispatcher;
if (defs) {
if (obj.$$is_class || obj.$$is_module) {
dispatcher = defs.$$super;
}
else {
dispatcher = obj.$$class.$$proto;
}
}
else {
dispatcher = Opal.find_obj_super_dispatcher(obj, jsid, current_func);
}
dispatcher = dispatcher['$' + jsid];
if (!defcheck && dispatcher.$$stub && Opal.Kernel.$method_missing === obj.$method_missing) {
// method_missing hasn't been explicitly defined
throw Opal.NoMethodError.$new('super: no superclass method `'+jsid+"' for "+obj, jsid);
}
return dispatcher;
};
Opal.find_iter_super_dispatcher = function(obj, jsid, current_func, defcheck, implicit)
Iter dispatcher for super in a block
Opal.find_iter_super_dispatcher = function(obj, jsid, current_func, defcheck, implicit) {
var call_jsid = jsid;
if (!current_func) {
throw Opal.RuntimeError.$new("super called outside of method");
}
if (implicit && current_func.$$define_meth) {
throw Opal.RuntimeError.$new("implicit argument passing of super from method defined by define_method() is not supported. Specify all arguments explicitly");
}
if (current_func.$$def) {
call_jsid = current_func.$$jsid;
}
return Opal.find_super_dispatcher(obj, call_jsid, current_func, defcheck);
};
klass = Opal.find_owning_class(klass, current_func)
first we need to find the class/module current_func is located on
klass = Opal.find_owning_class(klass, current_func);
``
repeating for readability
break
this klass was the last one the module donated to case is also hit with multiple module includes
break;
break
module has donated to other classes but klass isn't one of those
break;
break
cases like stdlib Singleton::included
that use a singleton of a singleton
break;
break
no modules, pure class inheritance
break;
while (klass)
now we can find the super
while (klass) {
break
ok
break;
Opal.ret = function(val)
Used to return as an expression. Sometimes, we can't simply return from a javascript function as if we were a method, as the return is used as an expression, or even inside a block which must "return" to the outer method. This helper simply throws an error which is then caught by the method. This approach is expensive, so it is only used when absolutely needed.
Opal.ret = function(val) {
Opal.returner.$v = val;
throw Opal.returner;
};
Opal.brk = function(val, breaker)
Used to break out of a block.
Opal.brk = function(val, breaker) {
breaker.$v = val;
throw breaker;
};
Opal.new_brk = function()
Builds a new unique breaker, this is to avoid multiple nested breaks to get in the way of each other.
Opal.new_brk = function() {
return new Error('unexpected break');
};
Opal.yield1 = function(block, arg)
handles yield calls for 1 yielded arg
Opal.yield1 = function(block, arg) {
if (typeof(block) !== "function") {
throw Opal.LocalJumpError.$new("no block given");
}
var has_mlhs = block.$$has_top_level_mlhs_arg,
has_trailing_comma = block.$$has_trailing_comma_in_args;
if (block.length > 1 || ((has_mlhs || has_trailing_comma) && block.length === 1)) {
arg = Opal.to_ary(arg);
}
if ((block.length > 1 || (has_trailing_comma && block.length === 1)) && arg.$$is_array) {
return block.apply(null, arg);
}
else {
return block(arg);
}
};
Opal.yieldX = function(block, args)
handles yield for > 1 yielded arg
Opal.yieldX = function(block, args) {
if (typeof(block) !== "function") {
throw Opal.LocalJumpError.$new("no block given");
}
if (block.length > 1 && args.length === 1) {
if (args[0].$$is_array) {
return block.apply(null, args[0]);
}
}
if (!args.$$is_array) {
var args_ary = new Array(args.length);
for(var i = 0, l = args_ary.length; i < l; i++) { args_ary[i] = args[i]; }
return block.apply(null, args_ary);
}
return block.apply(null, args);
};
Opal.rescue = function(exception, candidates)
Finds the corresponding exception match in candidates. Each candidate can be a value, or an array of values. Returns null if not found.
Opal.rescue = function(exception, candidates) {
for (var i = 0; i < candidates.length; i++) {
var candidate = candidates[i];
if (candidate.$$is_array) {
var result = Opal.rescue(exception, candidate);
if (result) {
return result;
}
}
else if (candidate['$==='](exception)) {
return candidate;
}
}
return null;
};
Opal.to_hash = function(value)
Helpers for extracting kwsplats Used for: { **h }
Opal.to_hash = function(value) {
if (value.$$is_hash) {
return value;
}
else if (value['$respond_to?']('to_hash', true)) {
var hash = value.$to_hash();
if (hash.$$is_hash) {
return hash;
}
else {
throw Opal.TypeError.$new("Can't convert " + value.$$class +
" to Hash (" + value.$$class + "#to_hash gives " + hash.$$class + ")");
}
}
else {
throw Opal.TypeError.$new("no implicit conversion of " + value.$$class + " into Hash");
}
};
``
Helpers for implementing multiple assignment Our code for extracting the values and assigning them only works if the return value is a JS array. So if we get an Array subclass, extract the wrapped JS array from it
Opal.to_ary = function(value)
Used for: a, b = something (no splat)
Opal.to_ary = function(value) {
if (value.$$is_array) {
return value;
}
else if (value['$respond_to?']('to_ary', true)) {
var ary = value.$to_ary();
if (ary === nil) {
return [value];
}
else if (ary.$$is_array) {
return ary;
}
else {
throw Opal.TypeError.$new("Can't convert " + value.$$class +
" to Array (" + value.$$class + "#to_ary gives " + ary.$$class + ")");
}
}
else {
return [value];
}
};
Opal.to_a = function(value)
Used for: a, b = *something (with splat)
Opal.to_a = function(value) {
if (value.$$is_array) {
// A splatted array must be copied
return value.slice();
}
else if (value['$respond_to?']('to_a', true)) {
var ary = value.$to_a();
if (ary === nil) {
return [value];
}
else if (ary.$$is_array) {
return ary;
}
else {
throw Opal.TypeError.$new("Can't convert " + value.$$class +
" to Array (" + value.$$class + "#to_a gives " + ary.$$class + ")");
}
}
else {
return [value];
}
};
Opal.extract_kwargs = function(parameters)
Used for extracting keyword arguments from arguments passed to JS function. If provided +arguments+ list doesn't have a Hash as a last item, returns a blank Hash.
@param parameters [Array] @return [Hash]
Opal.extract_kwargs = function(parameters) {
var kwargs = parameters[parameters.length - 1];
if (kwargs != null && kwargs['$respond_to?']('to_hash', true)) {
Array.prototype.splice.call(parameters, parameters.length - 1, 1);
return kwargs.$to_hash();
}
else {
return Opal.hash2([], {});
}
}
Opal.kwrestargs = function(given_args, used_args)
Used to get a list of rest keyword arguments. Method takes the given keyword args, i.e. the hash literal passed to the method containing all keyword arguemnts passed to method, as well as the used args which are the names of required and optional arguments defined. This method then just returns all key/value pairs which have not been used, in a new hash literal.
@param given_args [Hash] all kwargs given to method
@param used_args [Object
Opal.kwrestargs = function(given_args, used_args) {
var keys = [],
map = {},
key = null,
given_map = given_args.$$smap;
for (key in given_map) {
if (!used_args[key]) {
keys.push(key);
map[key] = given_map[key];
}
}
return Opal.hash2(keys, map);
};
Opal.send = function(recv, mid)
Call a ruby method on a ruby object with some arguments:
@example var my_array = [1, 2, 3, 4] Opal.send(my_array, 'length') # => 4 Opal.send(my_array, 'reverse!') # => [4, 3, 2, 1]
A missing method will be forwarded to the object via method_missing.
The result of either call with be returned.
@param recv [Object] the ruby object @param mid [String] ruby method to call @return [Object] forwards the return value of the method (or of method_missing)
Opal.send = function(recv, mid) {
var args_ary = new Array(Math.max(arguments.length - 2, 0));
for(var i = 0, l = args_ary.length; i < l; i++) { args_ary[i] = arguments[i + 2]; }
var func = recv['$' + mid];
if (func) {
return func.apply(recv, args_ary);
}
return recv.$method_missing.apply(recv, [mid].concat(args_ary));
};
Opal.defn = function(obj, jsid, body)
Used to define methods on an object. This is a helper method, used by the
compiled source to define methods on special case objects when the compiler
can not determine the destination object, or the object is a Module
instance. This can get called by Module#define_method
as well.
Modules
Any method defined on a module will come through this runtime helper.
The method is added to the module body, and the owner of the method is
set to be the module itself. This is used later when choosing which
method should show on a class if more than 1 included modules define
the same method. Finally, if the module is in module_function
mode,
then the method is also defined onto the module itself.
Classes
This helper will only be called for classes when a method is being
defined indirectly; either through Module#define_method
, or by a
literal def
method inside an instance_eval
or class_eval
body. In
either case, the method is simply added to the class' prototype. A special
exception exists for BasicObject
and Object
. These two classes are
special because they are used in toll-free bridged classes. In each of
these two cases, extra work is required to define the methods on toll-free
bridged class' prototypes as well.
Objects
If a simple ruby object is the object, then the method is simply just
defined on the object as a singleton method. This would be the case when
a method is defined inside an instance_eval
block.
@param obj [Object, Class] the actual obj to define method for @param jsid [String] the JavaScript friendly method name (e.g. '$foo') @param body [JS.Function] the literal JavaScript function used as method @return [null]
Opal.defn = function(obj, jsid, body) {
obj.$$proto[jsid] = body;
// for super dispatcher, etc.
body.$$owner = obj;
if (obj.$$is_module) {
Opal.donate(obj, jsid);
if (obj.$$module_function) {
Opal.defs(obj, jsid, body);
}
}
if (obj.$__id__ && !obj.$__id__.$$stub) {
var bridged = bridges[obj.$__id__()];
if (bridged) {
for (var i = bridged.length - 1; i >= 0; i--) {
Opal.bridge_method(bridged[i], obj, jsid, body);
}
}
}
var singleton_of = obj.$$singleton_of;
if (obj.$method_added && !obj.$method_added.$$stub && !singleton_of) {
obj.$method_added(jsid.substr(1));
}
else if (singleton_of && singleton_of.$singleton_method_added && !singleton_of.$singleton_method_added.$$stub) {
singleton_of.$singleton_method_added(jsid.substr(1));
}
return nil;
};
Opal.defs = function(obj, jsid, body)
Define a singleton method on the given object.
Opal.defs = function(obj, jsid, body) {
Opal.defn(Opal.get_singleton_class(obj), jsid, body)
};
if (!obj.$$eval && (obj.$$is_class || obj.$$is_module))
if instance_eval is invoked on a module/class, it sets inst_eval_mod
if (!obj.$$eval && (obj.$$is_class || obj.$$is_module)) {
Opal.rdef = function(obj, jsid)
Called from #remove_method.
Opal.rdef = function(obj, jsid) {
// TODO: remove from bridges as well
if (!$hasOwn.call(obj.$$proto, jsid)) {
throw Opal.NameError.$new("method '" + jsid.substr(1) + "' not defined in " + obj.$name());
}
delete obj.$$proto[jsid];
if (obj.$$is_singleton) {
if (obj.$$proto.$singleton_method_removed && !obj.$$proto.$singleton_method_removed.$$stub) {
obj.$$proto.$singleton_method_removed(jsid.substr(1));
}
}
else {
if (obj.$method_removed && !obj.$method_removed.$$stub) {
obj.$method_removed(jsid.substr(1));
}
}
};
Opal.udef = function(obj, jsid)
Called from #undef_method.
Opal.udef = function(obj, jsid) {
if (!obj.$$proto[jsid] || obj.$$proto[jsid].$$stub) {
throw Opal.NameError.$new("method '" + jsid.substr(1) + "' not defined in " + obj.$name());
}
Opal.add_stub_for(obj.$$proto, jsid);
if (obj.$$is_singleton) {
if (obj.$$proto.$singleton_method_undefined && !obj.$$proto.$singleton_method_undefined.$$stub) {
obj.$$proto.$singleton_method_undefined(jsid.substr(1));
}
}
else {
if (obj.$method_undefined && !obj.$method_undefined.$$stub) {
obj.$method_undefined(jsid.substr(1));
}
}
};
if (obj.$$eval)
instance_eval is being run on a class/module, so that need to alias class methods
if (obj.$$eval) {
``
Hashes
Opal.hash2 = function(keys, smap)
hash2 is a faster creator for hashes that just use symbols and strings as keys. The map and keys array can be constructed at compile time, so they are just added here by the constructor function
Opal.hash2 = function(keys, smap) {
var hash = new Opal.Hash.$$alloc();
hash.$$smap = smap;
hash.$$map = {};
hash.$$keys = keys;
return hash;
};
Opal.range = function(first, last, exc)
Create a new range instance with first and last values, and whether the range excludes the last value.
Opal.range = function(first, last, exc) {
var range = new Opal.Range.$$alloc();
range.begin = first;
range.end = last;
range.exclude = exc;
return range;
};
name === "constructor" ||
properties
name === "constructor" ||
name === "hasOwnProperty" ||
methods
name === "hasOwnProperty" ||
``
Require system
``
Initialization
Opal.boot_class_alloc('BasicObject', BasicObject_alloc)
Constructors for instances of core objects
Opal.boot_class_alloc('BasicObject', BasicObject_alloc);
Opal.BasicObject = BasicObject = Opal.setup_class_object('BasicObject', BasicObject_alloc, 'Class', Class_alloc)
Constructors for classes of core objects
Opal.BasicObject = BasicObject = Opal.setup_class_object('BasicObject', BasicObject_alloc, 'Class', Class_alloc);
BasicObject.$$class = Class
Fix booted classes to use their metaclass
BasicObject.$$class = Class;
BasicObject.$$super = null
Fix superclasses of booted classes
BasicObject.$$super = null;
_Object.$$proto.toString = function()
Forward .toString() to #to_s
_Object.$$proto.toString = function() {
return this.$to_s();
};
_Object.$$proto.$require = Opal.require
Make Kernel#require immediately available as it's needed to require all the other corelib files.
_Object.$$proto.$require = Opal.require;
Opal.top = new _Object.$$alloc()
Instantiate the top object
Opal.top = new _Object.$$alloc();
Opal.klass(_Object, _Object, 'NilClass', NilClass_alloc)
Nil
Opal.klass(_Object, _Object, 'NilClass', NilClass_alloc);