LegalRuleML

XML-based language for writing legal rules in machine-readable format.

A legal document written in LegalRuleML isn’t runnable by itself; just like an XML document isn’t a program but rather data.

Once you know roughly the type of thing LegalRuleML is, you can read Athan et al. (2015) LegalRuleML: Design Principles and Foundations. Before that, read the sample contract.

Sample contract

From Lam et al (2016).

r1: Goods marked as “Special Order” are subject to a 5% surcharge.

Rule 1 translates to LegalRuleML as follows.

Overview

<lrml:PrescriptiveStatement key="r1">
  <ruleml:Rule key=":ruletemplate1">
    [[[METADATA]]]
    <ACTUAL RULE CONTENT>
  </ruleml:Rule>
</lrml:PrescriptiveStatement>

It’s a prescriptive statement that has key r1, and it has a Rule in it. Inside the Rule, there is first some metadata and then the actual rule content.

Metadata

    <lrml:hasStrength>
      <lrml:DefeasibleStrength
         key="str1"
         iri="http://example.org/legalruleml/ontology#defeasible1"/>
    </lrml:hasStrength>

This rule has metadata about the rule strength: whether or not it can be overriden1. This rule can be, hence its strength is Defeasible. To make this not just meaningless characters on the contract writer’s computer, the property DefeasibleStrength refers to a shared resource by an IRI.

(These IRI links may point to an element in an Ontology#, but LegalRuleML is not an ontology language, and LegalRuleML documents are not ontologies.)

Rule content

Premise

    <ruleml:if>
      <ruleml:Atom key=":atom2">
        <ruleml:Rel iri=":specialOrder"/>
        <ruleml:Ind>X</ruleml:Ind>
      </ruleml:Atom>
    </ruleml:if>

It starts with a premise, constructed as an if-clause2. The syntax of LegalRuleML is clear enough: [[[if]]]statement[[[/if]]].

Inside the atom there are two things:

  • Relation: <ruleml:Rel iri=":specialOrder"/>
  • Individual: <ruleml:Ind>X</ruleml:Ind>.

Rel describes/refers to whatever the relation is, and Ind binds some individual X that we can refer to in the conclusion (then-clause). Two or more Atoms can be combined with And, Or.

Conclusion

    <ruleml:then>
      <lrml:Obligation>
        <ruleml:Atom key=":atom3">
          <ruleml:Rel iri=":surcharge"/>
          <ruleml:Ind>X</ruleml:Ind>
        </ruleml:Atom>
      </lrml:Obligation>
    </ruleml:then>

The conclusion completes the rule with an Obligation:

  • If an [[[Ind]]]X[[[/Ind]]] is marked as special order, (premise)
  • then that [[[Ind]]]X[[[/Ind]]] is subject to surcharge. (conclusion)

In addition to Obligation, there are other types of deontic operators, such as permissions, prohibitions, rights.

Comparison to other languages and tools

LegalRuleML is not for documenting laws, and it’s not for writing code, it’s for documenting legal rule expressions that may be implemented in code elsewhere.

Contrast with

  • Akoma Ntoso#, which is for documenting laws
  • ??? which is for writing code
  • TODO: other langs/tools and how it differs (eventually move to another page)

  1. By e.g. rule 2, which says “Premium customers are exempt from special order surcharge.”

    ↩︎

  2. Just like original does implicitly: “goods marked as special order” is syntactic sugar for “if good is marked as special order”.

    ↩︎
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