rubyx/lib/vool/statements/send_statement.rb
2017-09-06 12:51:24 +03:00

71 lines
2.4 KiB
Ruby

module Vool
class SendStatement < Statement
attr_reader :name , :receiver , :arguments
def initialize(name , receiver , arguments )
@name , @receiver , @arguments = name , receiver , arguments
@arguments ||= []
end
def collect(arr)
@receiver.collect(arr)
@arguments.each do |arg|
arg.collect(arr)
end
super
end
# 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)
#
# 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 weather the receiver type can be determined
#
# FIXME: we now presume direct (assignable) values for the arguments and receiver.
# in a not so distant future, temporary variables will have to be created
# and complex statements hoisted to assign to them. pps: same as in conditions
def to_mom( method )
Mom::Statements.new( message_setup + call_instruction )
end
def message_setup
pops = [Mom::SlotConstant.new([:message , :next_message , :receiver] , @receiver) ]
@arguments.each_with_index do |arg , index|
arg_target = [:message , :next_message , :arguments]
pops << Mom::SlotConstant.new( arg_target + [index] , arg)
end
pops
end
def call_instruction
if(@receiver.ct_type)
simple_call
else
cached_call
end
end
def simple_call
type = @receiver.ct_type
method = type.resolve_method(@name)
raise "No method #{@name} for #{type}" unless method
[Mom::SimpleCall.new( method) ]
end
def cached_call
raise "Not implemented"
[Mom::SlotConstant.new([:message , :next_message , :receiver] , @receiver) ]
end
end
end