rubyx/lib/vool/send_statement.rb
Torsten Rüger f87526f86f Renaming Vool exppressions rightly
Class, Method and Lambda (was block) are expressions.
Just making things clearer, especially for the blocks (ahem, lambdas) is matters.
wip
2019-08-19 11:33:12 +03:00

104 lines
3.8 KiB
Ruby

module Vool
# Sending in a dynamic language is off course not as simple as just calling.
# The function that needs to be called depends after all on the receiver,
# and no guarantees can be made on what that is.
#
# It helps to know that usually (>99%) the class of the receiver does not change.
# Our stategy then is to cache the functions and only dynamically determine it in
# case of a miss (the 1%, and first invocation)
#
# As cache key we must use the type of the object (which is the first word of _every_ object)
# as that is constant, and function implementations depend on the type (not class)
class SendStatement < CallStatement
attr_reader :block
def block
return nil if arguments.empty?
bl = arguments.last
bl.is_a?(BlockStatement) ? bl : nil
end
def add_block( block )
@arguments << block
end
def each(&block)
super
self.block.each(&block) if self.block
end
# lazy init this, to keep the dependency (which goes to parfait and booting) at bay
def dynamic_call
@dynamic ||= Mom::DynamicCall.new()
end
# A Send breaks down to 2 steps:
# - Setting up the next message, with receiver, arguments, and (importantly) return address
# - a CachedCall , or a SimpleCall, depending on wether the receiver type can be determined
def to_mom( compiler )
@receiver = SelfExpression.new(compiler.receiver_type) if @receiver.is_a?(SelfExpression)
if(@receiver.ct_type)
method = @receiver.ct_type.resolve_method(self.name)
return simple_call(compiler, method) if method
end
cached_call(compiler)
end
def message_setup(compiler,called_method)
setup = Mom::MessageSetup.new( called_method )
mom_receive = @receiver.to_slot(compiler)
arg_target = [:message , :next_message , :arguments]
args = []
@arguments.each_with_index do |arg , index| # +1 because of type
args << Mom::SlotLoad.new(self, arg_target + [index + 1] , arg.to_slot(compiler))
end
setup << Mom::ArgumentTransfer.new(self, mom_receive , args )
end
def simple_call(compiler, called_method)
message_setup(compiler,called_method) << Mom::SimpleCall.new(called_method)
end
# this breaks cleanly into two parts:
# - check the cached type and if neccessary update
# - call the cached method
def cached_call(compiler)
cache_check(compiler) << call_cached_method(compiler)
end
# check that current type is the cached type
# if not, change and find method for the type (simple_call to resolve_method)
# conceptually easy in ruby, but we have to compile that "easy" ruby
def cache_check(compiler)
ok = Mom::Label.new(self,"cache_ok_#{self.object_id}")
check = build_condition(ok, compiler) # if cached_type != current_type
check << Mom::SlotLoad.new(self,[dynamic_call.cache_entry, :cached_type] , receiver_type_definition(compiler))
check << Mom::ResolveMethod.new(self, @name , dynamic_call.cache_entry )
check << ok
end
# to call the method (that we know now to be in the cache), we move the method
# to reg1, do the setup (very similar to static) and call
def call_cached_method(compiler)
message_setup(compiler,dynamic_call.cache_entry) << dynamic_call
end
def to_s(depth = 0)
sen = "#{receiver}.#{name}(#{@arguments.collect{|a| a.to_s}.join(', ')})"
at_depth(depth , sen)
end
private
def receiver_type_definition(compiler)
defi = @receiver.to_slot(compiler)
defi.slots << :type
defi
end
def build_condition(ok_label, compiler)
cached_type = Mom::SlotDefinition.new(dynamic_call.cache_entry , [:cached_type])
current_type = receiver_type_definition(compiler)
Mom::NotSameCheck.new(cached_type , current_type, ok_label)
end
end
end