Hi, I have tried qualified imports, synonyms and newtypes but still I could not implement the merging task (previously posted). This is probably because I have little knowledge of Haskell *or* the task is not really suited to Haskell (more of a specification task than a programming task). My main questions are; Can the merging task be achieved using the Haskell module system? I also posted a question on how this task could be done using type classes. I would ask the same question with respect to type classes. Regards, Pat pat browne wrote:
Hi, I want to establish the strengths and weakness of the Haskell module system for the ontology merging task (I know it was not designed for this!). I wish to make a new module (MERGEDONTOLOGY) from three input modules one of which is common to the other two. The desired merge should contain the following data types: Woman FinancialBank HumanBeing RiverBank Which are all identifiable without any qualifying module names.
Below is the detailed requirement and my first attempt at this task in Haskell. I would be grateful for any information on how to merge these modules giving a set of unique unqualified types (i.e. without reference to their originating modules).
Regards, Pat
======================== Informal Specification ========================
The diagram and text below explain the requirement
MERGEDONTOLOGY { Woman, RiverBank, FinancialBank, HumanBeing} /\ /\ / \ / \ / \ / \ / \ / \
ONTOLOGY1 ONTOLOGY2 {Woman, Bank, Person} {Woman, Bank, Human} /\ /\ \ / \ / \ / \ / \ / \ / \ / {Woman , Person} COMMMON
This example includes both synonyms and homonyms. 1)The Woman sort (or data type) should be the same in all modules, there is only one Woman sort and it is named as such in each module. Hence there should be only one MERGEDONTOLOGY.Woman.
2)There is only one sort MERGEDONTOLOGY.HumanBeing, but there are 3 synonyms for it called ONTOLOGY2.Human, ONTOLOGY1.Person, and COMMON.Person. The last sentence considers ONTOLOGY1.Person and COMMON.Person as synonyms; they have different qualifiers but the intention is that they represnt the same thing. Hence should be mapped to same MERGEDONTOLOGY.HumanBeing. To do this (in Maude) COMMON.Person was renamed to ONTOLOGY2.Human which in turn was renamed to MERGEDONTOLOGY.HumanBeing.
3)The homonyms are ONTOLOGY1.Bank and ONTOLOGY2.Bank should become distinct sorts MERGEDONTOLOGY.RiverBank and MERGEDONTOLOGY.FinancialBank in the final ontology at the top of the diagram.
================================================ My first attemt at merging using Haskell modules ================================================= module COMMON where data Woman = WomanC data Person = PersonC
module ONTOLOGY1 where import COMMON data Bank = BankC
module ONTOLOGY2 where import COMMON data Bank = BankC
module MERGEDONTOLOGY where import ONTOLOGY1 import ONTOLOGY2
If I use qualified names all the constructors are interpreted correctly MERGEDONTOLOGY> :t COMMON.WomanC COMMON.WomanC :: COMMON.Woman MERGEDONTOLOGY> :t COMMON.PersonC COMMON.PersonC :: COMMON.Person MERGEDONTOLOGY> :t ONTOLOGY2.BankC ONTOLOGY2.BankC :: ONTOLOGY2.Bank MERGEDONTOLOGY> :t ONTOLOGY1.BankC ONTOLOGY1.BankC :: ONTOLOGY1.Bank MERGEDONTOLOGY> :t COMMON.Woman
However, I wish that these types and constructors be fully defined in the context of the MERGEDONTOLOGY. I have tried type synonyms and newtypes. type RiverBank = ONTOLOGY1.Bank type FinancialBank = ONTOLOGY2.Bank newtype RiverBank = BankC Int I have not explored import modes or qualified imports.