rubyx/lib/vool/yield_statement.rb
Torsten Ruger 1d2ec8e8ac abstract CallStatement base class, just like in ruby
to_mom differs much more than the to_vool in ruby,
but data and base functionality still warrent unification
also we can check for CallStatement now
2018-07-30 14:45:37 +03:00

64 lines
2.9 KiB
Ruby

module Vool
# A Yield is a lot like a Send, which is why they share the base class CallStatement
# That means it has a receiver (self), arguments and an (implicitly assigned) name
#
# On the ruby side, normalisation works pretty much the same too.
#
# On the way down to Mom, small differences become abvious, as the block that is
# yielded to is an argument. Whereas in a send it is either statically known
# or resolved and cached. Here it is dynamic, but sort of known dynamic.
# All we do before calling it is check that it is the right type.
class YieldStatement < CallStatement
# A Yield breaks down to 2 steps:
# - Setting up the next message, with receiver, arguments, and (importantly) return address
# - a SimpleCall,
def to_mom( compiler )
@parfait_block = @block.to_mom(compiler) if @block
@receiver = SelfExpression.new(compiler.receiver_type) if @receiver.is_a?(SelfExpression)
yield_call(compiler)
end
# this breaks into two parts:
# - check the calling method and break to a (not implemented) dynamic version
# - call the block, that is the last argument of the method
def yield_call(compiler)
method_check(compiler) << yield_arg_block(compiler)
end
# check that the calling method is the method that the block was created in.
# In that case variable resolution is reasy and we can prceed to yield
# Note: the else case is not implemented (ie passing lambdas around)
# this needs run-time variable resolution, which is just not done.
# we brace ourselves with the check, and exit (later raise) if . . .
def method_check(compiler)
ok_label = Mom::Label.new("method_ok_#{self.object_id}")
compile_method = Mom::SlotDefinition.new( compiler.get_method , [])
runtime_method = Mom::SlotDefinition.new( :message , [ :method] )
check = Mom::NotSameCheck.new(compile_method , runtime_method, ok_label)
# TODO? Maybe create mom instructions for this
#builder = compiler.code_builder("yield")
#Risc::Builtin::Object.exit_sequence(builder)
#check << builder.built
check << ok_label
end
# to call the block (that we know now to be the last arg),
# we do a message setup, arg transfer and the a arg_yield (which is similar to dynamic_call)
def yield_arg_block(compiler)
arg_index = compiler.get_method.arguments_type.get_length - 1
setup = Mom::MessageSetup.new( arg_index )
mom_receive = @receiver.slot_definition(compiler)
arg_target = [:message , :next_message , :arguments]
args = []
@arguments.each_with_index do |arg , index| # +1 because of type
args << Mom::SlotLoad.new( arg_target + [index + 1] , arg.slot_definition(compiler))
end
setup << Mom::ArgumentTransfer.new( mom_receive , args )
setup << Mom::BlockYield.new( arg_index )
end
end
end