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994 Commits (82a02c0081b6ffd8c3bd1c65ac098ae4be1c21f6)

Author SHA1 Message Date
Mike Gerwitz 82a02c0081 [copyright] Copyright assignment to the FSF
Thanks to Donald Robertson III for his help and guidance during this
process.
2014-04-09 19:05:07 -04:00
Mike Gerwitz 9c70904c39
Private method wrapping eliminated
This has wonderful consequences; see branch commits for more information.
2014-03-20 23:55:32 -04:00
Mike Gerwitz 74b4525f00
Added details of private method wrapping exemption to manual 2014-03-20 23:55:16 -04:00
Mike Gerwitz c835641dcb Private methods are no longer wrapped
This is an exciting performance optimization that seems to have eluded me
for a surprisingly long time, given that the realization was quite random.
ease.js accomplishes much of its work through a method wrapper---each and
every method definition (well, until now) was wrapped in a closure that
performed a number of steps, depending on the type of wrapper involved:

  1. All wrappers perform a context lookup, binding to the instance's private
     member object of the class that defined that particular method. (See
     "Implementation Details" in the manual for more information.)
  2. This context is restored upon returning from the call: if a method
     returns `this', it is instead converted back to the context in which
     the method was invoked, which prevents the private member object from
     leaking out of a public interface.
  3. In the event of an override, this.__super is set up (and torn down).

There are other details (e.g. the method wrapper used for method proxies),
but for the sake of this particular commit, those are the only ones that
really matter. There are a couple of important details to notice:

  - Private members are only ever accessible from within the context of the
    private member object, which is always the context when executing a
    method.
  - Private methods cannot be overridden, as they cannot be inherited.

Consequently:

  1. We do not need to perform a context lookup: we are already in the proper
     context.
  2. We do not need to restore the context, as we never needed to change it
     to begin with.
  3. this.__super is never applicable.

Method wrappers are therefore never necessary for private methods; they have
therefore been removed.

This has some interesting performance implications. While in most cases the
overhead of method wrapping is not a bottleneck, it can have a strong impact
in the event of frequent method calls or heavily recursive algorithms. There
was one particular problem that ease.js suffered from, which is mentioned in
the manual: recursive calls to methods in ease.js were not recommended
because it

  (a) made two function calls for each method call, effectively halving the
      remaining call stack size, and
  (b) tail call optimization could not be performed, because recursion
      invoked the wrapper, *not* the function that was wrapped.

By removing the method wrapper on private methods, we solve both of these
problems; now, heavily recursive algorithms need only use private methods
(which could always be exposed through a protected or public API) when
recursing to entirely avoid any performance penalty by using ease.js.

Running the test cases on my system (your results may vary) before and after
the patch, we have:

  BEFORE:
  0.170s (x1000 = 0.0001700000s each): Declare 1000 anonymous classes with
    private members
  0.021s (x500000 = 0.0000000420s each): Invoke private methods internally

  AFTER:
  0.151s (x1000 = 0.0001510000s each): Declare 1000 anonymous classes with
    private members
  0.004s (x500000 = 0.0000000080s each): Invoke private methods internally

This is all the more motivation to use private members, which enforces
encapsulation; keep in mind that, because use of private members is the
ideal in well-encapsulated and well-factored code, ease.js has been designed
to perform best under those circumstances.
2014-03-20 23:43:24 -04:00
Mike Gerwitz f9e8390a55
Updated homepage and git repo URLs 2014-03-20 23:42:53 -04:00
Mike Gerwitz b413343e42
Version bump: 0.2.1-dev 2014-03-20 23:41:14 -04:00
Mike Gerwitz 2ebff67b36
Package rename in configure.ac (remove dot) 2014-03-16 01:02:12 -04:00
Mike Gerwitz 38ab859a4c
Version bump to 0.2.0
From 0.2.0-dev
2014-03-16 00:11:47 -04:00
Mike Gerwitz 2665518e01
Added README.traits to distribution 2014-03-16 00:10:11 -04:00
Mike Gerwitz 3a625ccf28
Merge branch 'authors' 2014-03-16 00:06:36 -04:00
Mike Gerwitz 3f28a6ae19 AUTHORS file will now contain and sort by commit count 2014-03-16 00:06:17 -04:00
Mike Gerwitz 97f42a275c Added .mailmap
Join personal and GNU e-mail identities
2014-03-16 00:03:02 -04:00
Mike Gerwitz 10d653825a
Corrected version string generation with empty suffix 2014-03-15 23:57:02 -04:00
Mike Gerwitz 744696b1a7
[copyright] Copyright update 2014-03-15 23:56:47 -04:00
Mike Gerwitz ac1a0368cf
Preliminary support for traits as mixins
This has turned out to be a very large addition to the project---indeed,
with this release, its comprehensiveness remains elusive, but this is a huge
step in the right direction.

Traits allow for powerful methods of code reuse by defining components that
can be ``mixed into'' classes, almost as if the code were copied and pasted
directly into the class definition. Mixins, as they are so called, carry
with them the type of the trait, just as implementing an interface carries
with it the type of the interface; this means that they integrate into
ease.js' type system such that, given some trait T that mixes into class C
and an instance of C, it will be true that Class.isA( T, inst ).

The trait implementation for GNU ease.js is motivated heavily by Scala's
implementation of mixins using traits. Notable features include:

  1. Traits may be mixed in either prior to or following a class definition;
     this allows coupling traits tightly with a class or allowing them to be
     used in a decorator-style manner prior to instantiation.

  2. By mixing in a trait prior to the class definition, the class may
     override methods of the trait:

       Class( 'Foo' ).use( T ).extend( { /*...*/ } )

     If a trait is mixed in after a class definition, then the trait may
     instead override the functionality of a class:

       Class( 'Foo', { /*...*/ } ).use( T )

  3. Traits are stackable: By using the `abstract override' keyword
     combination, a trait can override the concrete definition of its
     parent, provided that the abstract definition is implemented by the
     trait (e.g. by implementing a common interface). This allows overrides
     to be mixed in any order. For example, consider some class Buffer that
     defines an `add' method, accepting a string. Now consider two traits
     Dup and Upper:

       Buffer.use( Dup ).use( Upper )().add( "foo" )

     This would result in the string "FooFoo" being added to the buffer.
     On the other hand:

       Buffer.use( Reverse ).use( Dup )().add( "foo" )

     would add the string "Foofoo".

  4. A trait may maintain its own private state and API completely disjoint
     from the class that it is mixed into---a class has access only to
     public and protected members of a trait and vice versa. This further
     allows a class and trait to pass messages between one-another without
     having their communications exposed via a public API. A trait may even
     communicate with with other traits mixed into the same class (or its
     parents/children), given the proper overrides.

Traits provide a powerful system of code reuse that solves the multiple
inheritance problems of languages like C++, without introducing the burden
and code duplication concerns of Java's interfaces (note that GNU ease.js
does support interfaces, but not multiple inheritance). However, traits also
run the risk of encouraging overly rich APIs and complicated inheritance
trees that produce a maintenance nightmare: it is important to keep concerns
separated, creating classes (and traits) that do one thing and do it well.
Users should understand the implications of mixing in traits prior to the
class definition, and should understand how decorating an API using mixins
after a class definition tightly couples the trait with all objects derived
from the generated class (as opposed to the flexibility provided by the
composition-based decorator pattern). These issues will be detailed in the
manual once the trait implementation is complete.

The trait implementation is still under development; outstanding tasks are
detailed in `README.traits`. In the meantime, note that the implementation
*is* stable and can be used in the production environment. While
documentation is not yet available in the manual, comprehensive examples and
rationale may be found in the trait test cases.

Happy hacking!
2014-03-15 23:50:21 -04:00
Mike Gerwitz 00a4ff6786 README.traits containing remaining TODOs 2014-03-15 22:19:07 -04:00
Mike Gerwitz 0713a9f3d0 Deleted unnecessary trait abstract method in favor of auto-abstract flag
This method was added before this flag existed.
2014-03-15 21:16:27 -04:00
Mike Gerwitz cc43f4b339 Prohibiting trait getters/setters 2014-03-15 21:16:27 -04:00
Mike Gerwitz bfadd9fce9 Added missing trait docblocks 2014-03-15 21:16:27 -04:00
Mike Gerwitz eab4dbfe4d Throwing exception on trait static member
These will be supported in future versions; this is not something that I
want to rush, nor is it something I want to hold up the first GNU release;
it is likely to be a much lesser-used feature.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 316a7dd703 Refactored Traits to use propParse hooks 2014-03-15 21:16:27 -04:00
Mike Gerwitz 3d47443046 Refactored ClassBuilder.buildMembers (dynamic prop parse context)
The parser methods are now split into their own functions. This has a number
of benefits: The most immediate is the commit that will follow. The second
benefit is that the function is no longer a closure---all context
information is passed into it, and so it can be optimized by the JavaScript
engine accordingly.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 7d27bc7969 Exposing Trait module
Oh boy oh boy oh boy!
2014-03-15 21:16:27 -04:00
Mike Gerwitz c5b6562d34 Mention of "Traits as mixins" in README.md and manual
No documentation yet; this is planned for the 0.2.1 release to prevent
further delays of the first GNU release.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 255a60e425 Implemented and abstract with mixins properly handled
Classes will now properly be recognized as concrete or abstract when mixing
in any number of traits, optionally in conjunction with interfaces.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 696b8d05a6 Class definition mixin now requires explicit extend
See the rather verbose docblocks in this diff for more information.
Additional rationale will be contained in the commits that follow.
2014-03-15 21:16:27 -04:00
Mike Gerwitz a7e381a31e Mixing method invocation performance tests
As expected, mixin method invocation is dramatically slower than
conventional class method definitions. However, it is a bit slower than I
had anticipated; future releases will definately need to take a look at
improving performance, which should happen anyway, since the trait
implementation takes the easy way out in a number of instances.

Let's get an initial release first.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 433dd4fb7a Trait definition and mixin performance test cases
Does not yet include many more detailed tests, such as method invocation
times, which will be of particular interest. While definitions are indeed
interesting, they often occur when a program is loading---when the user is
expecting to wait. Not so for method invocations.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 55e993a74d Non-private properties now expressly prohibited in trait dfns
:O What?! See Trait/PropertyTest for more information on why this is the
case, at least for now.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 3005cda543 Support for stacked mixins
The concept of stacked traits already existed in previous commits, but until
now, mixins could not be stacked without some ugly errors. This also allows
mixins to be stacked atop of themselves, duplicating their effect. This
would naturally have limited use, but it's there.

This differs slightly from Scala. For example, consider this ease.js mixin:

  C.use( T ).use( T )()

This is perfectly valid---it has the effect of stacking T twice. In reality,
ease.js is doing this:

  - C' = C.use( T );
  - new C'.use( T );

That is, it each call to `use' creates another class with T mixed in.

Scala, on the other hand, complains in this situation:

  new C with T with T

will produce an error stating that "trait T is inherited twice". You can
work around this, however, by doing this:

  class Ca extends T
  new Ca with T

In fact, this is precisely what ease.js is doing, as mentioned above; the
"use.use" syntax is merely shorthand for this:

  new C.use( T ).extend( {} ).use( T )

Just keep that in mind.
2014-03-15 21:16:27 -04:00
Mike Gerwitz dd7b062474 Base class now has __cid assigned to 0 2014-03-15 21:16:27 -04:00
Mike Gerwitz 311496fbe4 Virtual mixin need not be weak
This is a relic from the initial implementation, before the abstract/concrete
separation.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 88713987e2 Mixin use method calls can now be chained
Syntatic sugar; could have previously extended explicitly and then mixed in.
2014-03-15 21:16:27 -04:00
Mike Gerwitz 8480d8f92c Added support for abstract overrides 2014-03-15 21:16:27 -04:00
Mike Gerwitz 14bd552361 Trait can now implement interfaces
Note the incomplete test case: the next commit will introduce the ability
for mixins to override methods that may have already been defined.
2014-03-15 21:16:27 -04:00
Mike Gerwitz c8023cb382 Trait method return value implementation correction and testing 2014-03-15 21:16:27 -04:00
Mike Gerwitz 6473cf35ae Began Scala-influenced linearization implementation
More information on this implementation and the rationale behind it will
appear in the manual. See future commits.

(Note the TODOs; return values aren't quite right here, but that will be
handled in the next commit.)
2014-03-15 21:16:27 -04:00
Mike Gerwitz 75e1470582 Class.use now creates its own class 2014-03-15 21:16:27 -04:00
Mike Gerwitz 8d81373ef8 Began named trait implementation
Does not yet support staging object like classes
2014-03-15 21:16:27 -04:00
Mike Gerwitz 26bd6b88dd Named classes now support mixins 2014-03-15 21:16:27 -04:00
Mike Gerwitz 455d3a5815 Added immediate partial class invocation support after mixin 2014-03-15 21:16:27 -04:00
Mike Gerwitz 897a4afab4 Added support for mixing in traits using use method on a base class 2014-03-15 21:16:27 -04:00
Mike Gerwitz 999c10c3bf Subtype mixin support 2014-03-15 21:16:27 -04:00
Mike Gerwitz 451ec48a5c Objects are now considered types of class's mixed in traits
This is a consequence of ease.js' careful trait implementation that ensures
that any mixed in trait retains its API in the same manner that interfaces
and supertypes do.
2014-03-15 21:16:27 -04:00
Mike Gerwitz ee46fc2182 Began testing class subtyping with mixins 2014-03-15 21:16:27 -04:00
Mike Gerwitz 513bd1a733 Added test case for visibility escalation internally
For completeness, since this is how I originally observed the issue fixed in
the previous commit.
2014-03-15 21:16:26 -04:00
Mike Gerwitz bcada87240 [bug fix] Corrected bug with implicit visibility escalation
See test case comments for details. This wasted way too much of my time.
2014-03-15 21:16:26 -04:00
Mike Gerwitz 5047d895c0 Moved closure out of getMemberVisibility
This was defining a function on every call for no particular reason other
than being lazy, it seems.

Performance poopoo.
2014-03-15 21:16:26 -04:00
Mike Gerwitz 66cab74cc1 Initial trait virtual member proxy implementation
This has some flaws that should be addressed, but those will be detailed in
later commits; this works for now.
2014-03-15 21:16:26 -04:00
Mike Gerwitz 3c7cd0e57a Added virtual members to class metadata
There does not seem to be tests for any of the metadata at present; they are
implicitly tested through various implementations that make use of them.
This will also be the case here ("will"---in coming commits), but needs to
change.

The upcoming reflection implementation would be an excellent time to do so.
2014-03-15 21:16:26 -04:00