rubyx/lib/ast/basic_expressions.rb
2014-09-14 18:14:57 +03:00

101 lines
3.2 KiB
Ruby

# collection of the simple ones, int and strings and such
module Ast
# Constant expressions can by definition be evaluated at compile time.
# But that does not solve their storage, ie they need to be accessible at runtime from _somewhere_
# So we view ConstantExpressions like functions that return the value of the constant.
# In other words, their storage is the return slot as it would be for a method
# The current approach moves the constant into a varaible before using it
# But in the future (in the one that holds great things) we optimize those unneccesay moves away
class IntegerExpression < Expression
# attr_reader :value
def compile method , message
to = Virtual::NewReturn.new(Virtual::Integer)
method.add_code Virtual::Set.new( to , Virtual::IntegerConstant.new(value))
to
end
end
class TrueExpression
def compile method , message
to = Virtual::Return.new(Virtual::Reference)
method.add_code Virtual::Set.new( to , Virtual::TrueConstant.new )
to
end
end
class FalseExpression
def compile method , message
to = Virtual::Return.new(Virtual::Reference)
method.add_code Virtual::Set.new( to , Virtual::FalseConstant.new )
to
end
end
class NilExpression
def compile method , message
to = Virtual::Return.new(Virtual::Reference)
method.add_code Virtual::Set.new( to , Virtual::NilConstant.new )
to
end
end
class NameExpression < Expression
# attr_reader :name
# compiling name needs to check if it's a variable and if so resolve it
# otherwise it's a method without args and a send is ussued.
# this makes the namespace static, ie when eval and co are implemented method needs recompilation
def compile method , message
return Virtual::Self.new( Virtual::Mystery ) if name == :self
if method.has_var(name)
message.compile_get(method , name )
else
raise "Unimplemented #{self}"
message.compile_send( method , name , Virtual::Self.new( Virtual::Mystery ) )
end
end
end
class ModuleName < NameExpression
def compile method , message
to = Virtual::Return.new(Virtual::Reference)
clazz = ::Virtual::BootSpace.space.get_or_create_class name
raise "uups #{clazz}.#{name}" unless clazz
method.add_code Virtual::Set.new( to , clazz )
to
end
end
class StringExpression < Expression
# attr_reader :string
def compile method , message
to = Virtual::Return.new(Virtual::Reference)
value = Virtual::StringConstant.new(string)
Virtual::BootSpace.space.add_object value
method.add_code Virtual::Set.new( to , value )
to
end
end
class AssignmentExpression < Expression
#attr_reader :left, :right
def compile method , message
raise "must assign to NameExpression , not #{left}" unless left.instance_of? NameExpression
r = right.compile(method,message)
raise "oh noo, nil from where #{right.inspect}" unless r
message.compile_set( method , left.name , r )
end
end
class VariableExpression < NameExpression
def compile method , message
method.add_code Virtual::InstanceGet.new(name)
Virtual::NewReturn.new( Virtual::Mystery )
end
end
end