1 files changed, 32 insertions(+), 19 deletions(-)

M lib/em_promise.rb

@@ 8,28 8,51 @@ class EMPromise < Promise
 	class Trampoline
 		attr_accessor :ready
 
-		def initialize
+		class SubmittedBlock
+			def initialize(blk)
+				@blk = blk
+			end
+
+			def call(*args, **kwargs, &blk)
+				@blk.call(*args, **kwargs, &blk)
+			end
+		end
+
+		def initialize(&initial_blk)
 			@ready = true
 			@fiber = Fiber.new do |blk|
 				Thread.current[:_em_promise_trampoline] = self
-				loop do
-					self.ready = false
-					result = blk.call
-					self.ready = true
-					blk = Fiber.yield result
-				end
+				self.ready = false
+				Trampoline.yield(blk.call)
 			end
+			@fiber.resume(&initial_blk) if initial_blk
 		end
 
 		def submit(&blk)
 			EM.next_tick do
 				if ready
-					@fiber.resume(blk)
+					@fiber.resume(SubmittedBlock.new(blk))
 				else
 					submit(&blk)
 				end
 			end
 		end
+
+		def self.yield(arg=nil)
+			tramp = Thread.current[:_em_promise_trampoline]
+			raise "Trampoline already ready?" if tramp&.ready
+
+			loop do
+				tramp&.ready = true
+				blk = Fiber.yield arg
+				tramp&.ready = false
+				if blk.is_a?(SubmittedBlock)
+					arg = blk.call
+				else
+					return arg
+				end
+			end
+		end
 	end
 
 	# Make sure that self.class.new inherits the trampoline


@@ 73,17 96,7 @@ class EMPromise < Promise
 		self.then(resume, resume)
 
 		# We might be in a trampoline, so keep that going
-		tramp = Thread.current[:_em_promise_trampoline]
-		raise "Trampoline already ready?" if tramp&.ready
-
-		result = nil
-		loop do
-			tramp&.ready = true
-			blk = Fiber.yield result
-			tramp&.ready = false
-			result = blk&.call
-			break unless blk
-		end
+		Trampoline.yield
 	end
 
 	def self.reject(e)