129 lines
6.1 KiB
Plaintext
129 lines
6.1 KiB
Plaintext
%p
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In short, class methods are working. Plus is some meta stuff that and gotchas that
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i will explain below. Also i was at presenting rubyx at the first international
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conference, and there are a couple of misc improvements.
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%h2 Classes are Singleton objects
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%p
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Class methods came up when parsing Parfait. To create objects we usually use new, a
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class method. After briefly contemplating to hack that and use the global space
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object, i decided to at least check it out. And since it wasn't so bad, i continued.
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%p
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At some point i thought class methods would be very simple, as they are just methods on
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another object. After all the way we write code in classes is just a way to define methods
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on a group of objects. And defining class methods "just" changes which objects we
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define the methods on. And for the most part, this view is true. The only main difference
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is that class objects are singletons.
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%h2 Singletons means singleton classes
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%p
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Since we want to define methods on the single object, (and we are not programming
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javascript) we need a class like object that allows us to define these methods and
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manages them. There are several ways to do this, and i opted for a rather explicit
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one for now.
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%p
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So i created a class called MetaClass, that is more or less like a Class. It does
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currently not derive, just implements the same protocol. In the compiler it can
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be used as a replacement for a class object, and that is exactly what we do.
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A metaclass instance is created for every class instance and there is a one to one
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relation with the class object.
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%p
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Ruby does this in a more general way, and that off course means that at some point
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rubyx will have to move there too. In ruby every object has a singleton (meta) class.
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This must be implemented with lasy creation, otherwise it seems very wasteful.
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In Ruby the Metaclass is just a class, which means it has a metaclass, and
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at the moment i have other problems than keeping my brain from melting by thinking
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in circles like that.
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%h2 Compiling class methods
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%p
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Actual compilation now becomes very simple. Before we were passing the class in
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when compiling a method. Now we have methods and class methods, and depending on
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which kind it is, we use a different object. The class object for method, and the classes
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metaclass object for class methods.
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%p
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Sort of surprisingly, none of the code further down had to be changed. But there are
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no tests yet for all the possible features, so there may be surprises. Also interpreting
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a class method call worked straight away, no changes needed there.
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%p
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Class instance variables also have no tests, and so i don't know if they work or how
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much work that would be. I sort of hope not much, but there clearly is an issue with
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the types changing that will have to be addressed.
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%h2 Change, specifically changing types
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%p
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As Types never change, we always create new instances. This works for normal objects, as
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we can just use the new type for new objects. Also while compiling a binary (ie not on
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the fly yet), we can just use the latest type for all existing objects of a class
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when we create the binary.
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%p
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For singletons this hack does not work. Especially when adding class instance variables,
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the actual type of the existing class object changes. This means we have to change
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the type reference in the class object. This in turn means the new type has to be
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binary compatible with the old, which basically means it can't grow beyond the
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allocated size.
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%p
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This has been on the horizon for objects since the whole type idea was implemented.
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Just the horizon was always far away, and now i have to see how much of this can
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be done easily, how much later. We'll see, tests will tell.
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%h2 Misc other
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%p
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Other things have happened that are maybe worth mentioning.
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%h3 Ruby integer upgrade
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%p
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Since i started before 2.4 there were still uses of Fixnum. In 2.4 Integer and Fixnum
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were united and later versions created a whole ton of warning. So i had stuck with 2.3
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until now.
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%p
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Now all Fixnums are gone and i have upgraded to use 2.6.
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%h3 Object creation
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%p
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When doing the Factories i hardcoded some page sizes. Hardcoding always bites you, as
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they should teach everyone in kindergarten, and so it did. It massively increased
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the test times, as for every Parfait boot (almost every test) several pages worth
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of objects were created.
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%p
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I have now made the page size configurable and for good measure am passing some
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config into the compiler. The compiler then passes a parfait key down, a mechanism
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that could easily be extended to other subsystems.
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%p
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The result was that test times have more than halved. Which means my new machine
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(the one i am just choosing) does not have to be quite as expensive :-)
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%h3 Command Line Interface
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%p
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Since i am hoping that people will start playing with ruby-x at some point i thought
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to make that easier. This has been out there for a while as well, but since the set
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of features was so small it just didn't get done before.
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%p
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So now we have a thor based cli in the bin directory. Not that it does so terribly much
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yet, but at least you can invoke it, get some help, and compile a ruby to binary.
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Platforms are not supported (as we only have arm) and those Parfait options neither.
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But a start.
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%h3 Rubyconf talk
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.container
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%p.full_width
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=image_tag "rubyconf.jpg"
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%p
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Last but not least, i had the
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=ext_link "first talk" , "https://twitter.com/_swanand/status/1087279289672785920"
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at a conference. At the RubyConf in India, Goa
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to be specific. Many people were really interested, and Sherif and the organisers we very
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friendly. Off course we had a nice holiday too. No video yet, but i put the slides up on
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the homepage.
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%h2 Work continues
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%p
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When starting two big projects at work last year i didn't have so much time, and there
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were months when i had no juice to code. Now i am on part time (physical) work again
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and am back chipping away at it.
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%p
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I am still looking for people to join and will increase the effort a bit now that
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at least a reasonable subset is working.
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%p
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Welcome!
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