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whenever Rubymotion returns a symbol of the def-expr, async and await like c# will be possible
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| module AsyncAwait | |
| class Task < NSOperation | |
| def self.new(&block) | |
| alloc.initWithBlock(block) | |
| end | |
| def initWithBlock(block) | |
| init.tap do | |
| @status = :ready | |
| @action = block | |
| @executing = false | |
| @finished = false | |
| end | |
| end | |
| attr_reader :status, :result, :exception | |
| def isConcurrent; true; end | |
| def isExecuting; @executing; end | |
| def isFinished; @finished; end | |
| def start | |
| @status = :executing | |
| # Always check for cancellation before launching the task. | |
| if self.cancelled? | |
| # Must move the operation to the finished state if it is canceled. | |
| self.willChangeValueForKey('isFinished') | |
| @finished = true | |
| self.didChangeValueForKey('isFinished') | |
| return | |
| end | |
| # If the operation is not canceled, begin executing the task. | |
| @executing = true | |
| super | |
| end | |
| def main | |
| @result = @action.call | |
| rescue Exception => exception | |
| @exception = exception | |
| ensure | |
| completeOperation | |
| end | |
| def inspect | |
| NSString.stringWithString description.gsub(':', self.finished? ? " [#{@result.class}]:" : " @status=#@status:") | |
| end | |
| alias to_s inspect | |
| private | |
| def completeOperation | |
| @status = :finished | |
| self.willChangeValueForKey('isFinished') | |
| self.willChangeValueForKey('isExecuting') | |
| @executing = false | |
| @finished = true | |
| self.didChangeValueForKey('isFinished') | |
| self.didChangeValueForKey('isExecuting') | |
| end | |
| end | |
| ### methods | |
| def __queue__ | |
| @@__queue__ ||= NSOperationQueue.new.tap do |queue| | |
| queue.name = "async.await.queue.#{object_id}" | |
| queue.maxConcurrentOperationCount = NSOperationQueueDefaultMaxConcurrentOperationCount | |
| end | |
| end | |
| # this will create a new method with 'async_' Prefix | |
| def async(method_name) | |
| original = instance_method(method_name) | |
| wrapper("async_#{method_name}".to_sym, original) | |
| end | |
| # this will override your method | |
| def async!(method_name) | |
| original = instance_method(method_name) | |
| wrapper(method_name.to_sym, original) | |
| end | |
| private | |
| def wrapper(method_name, original) | |
| define_method(method_name) do |*args, &block| | |
| task = Task.new do | |
| result = original.bind(self).call(*args, &block) | |
| #yield(result) | |
| end | |
| self.class.__queue__.addOperation(task) | |
| task | |
| end | |
| end | |
| def self.included(receiver) | |
| receiver.extend self | |
| end | |
| end | |
| module Kernel | |
| def await!(task) | |
| return nil unless task.is_a?(AsyncAwait::Task) | |
| task.waitUntilFinished | |
| task.instance_variable_get(:@result) | |
| end | |
| end |
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| class HTTPClient | |
| include AsyncAwait | |
| def get_string(url) | |
| nsurl = NSURL.URLWithString(url) | |
| sleep 2.0 | |
| content = NSString.stringWithContentsOfURL(nsurl, encoding:NSASCIIStringEncoding) | |
| end | |
| async(:get_string) | |
| # unfortunatelly rubymotion doesn't support yet 'value of def-expr' which return a symbol when | |
| # defining a method. What would be possible?! well, this.... | |
| async def getURL(url) | |
| nsurl = NSURL.URLWithString(url) | |
| sleep 2.0 | |
| content = NSString.stringWithContentsOfURL(nsurl, encoding:NSASCIIStringEncoding) | |
| end | |
| end | |
| client = HTTPClient.new | |
| task = client.async_get_string('http://msdn.microsoft.com') | |
| puts "lets do something else! #{task}" # => lets do something else <Task @status=executing: 0x7fa361f95c30> | |
| response = await! task | |
| puts response # =><!DOCTYPE html>\n\n\n\n\n<html dir=\"ltr\" lang=\"en\"... |
@mattgreen, I remember we talked about this in Brussels, with callcc we would only call the awaited with the current continuation? is it right?
btw: nice to see you here, are you taking sabbatical time?
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Well done. Now we just need callcc to work to fully replicate async/await. :)
In the past, I've experimented with using setjmp/longjmp to restore the stack pointer (in lieu of
waitUntilFinished), but without the ability to interact with the 'GC' it isn't useful at all.