[MLton-user] withtype and and disparity

[Raymond Racine]

structure ReteTypes =
struct

datatype rete_node = 
	 EmptyNode |
	 BetaNode of {parent: rete_node, children: rete_node list ref} |
	 JoinNode of {parent: rete_node, children: rete_node list ref,
alphaMemory: alpha_node} |
	 ProductionNode of {parent: rete_node, alphaNetwork: alpha_network}
withtype alpha_node = {successors: rete_node list ref}
and  alpha_network = {an: alpha_node}
end


The above code snip compiles in SML/NJ, does not in MLton.  

I don't know if there is bug or this is ambiguous area of the spec open
to implementation interpretation.  But I would like to be able to
compile it or its equivalent in MLTon.

Thanks in advance.

Regards,

Ray