GDL2 Object Model

Representation of a discrete guideline, which defines archetype bindings, rules and descriptive meta-data.

Identification of this guideline. Syntax is a string of format:

For example: calculate_bmi.v1.

The version of the GDL the guide is written in, in a string of format:

i.e. a 2- or 3-number form of version, e.g. "1.0", "2.0", etc.

The normative meaning of the guideline as whole. Expressed as a gt-code.

The main definition part of the guide. It consists of archetype bindings and rule definitions.

Terminology definitions of the guideline containing definitions and translations (if applicable) for every gt-code.

The definition of the guideline includes:

List of archetype/template bindings, which define specific elements to be used by rules in this guideline.

Pre-conditions to be met before the guideline can be selected for execution. Pre-conditions constitute the definition of the guideline 'entry point', i.e. the match to a patient type to which the guideline may apply.

Map of rules indexed by local gt codes.

Actions that will always be performed, whenever the when conditions are evaluated, regardless of the result.

One or more output termplates that define how to represent output reporting structure.

Variables used internally to a GDL guideline, i.e. not bound to external data entities. These are generated during parsing of expressions and used to track interim state.

A single rule defined in a guideline, of the logical form

when conditions then actions.

Conditions are assertions based on input and/or environment variables (e.g.time, date etc). Actions take the form of assignments to output variables.

The gt-code of this rule.

List of assertions that when evaluated to True cause the rule to be fired. The when assertions may only mention 'input' type variables.

List of actions if the rule is fired. Each action is in the form of an assignment to an 'output' type variable.

Indicates the evaluation order of Rules within a Guideline. Rules with a higher priority value are executed first.

A list of bindings of nodes for a data-set' - i.e. from the archetype (and optionally template) specified by archetype_id and template_id respectively, to guideline variables, each specified by an element binding.

The identifier of the data-set model (i.e. archetype or other) from which the list of elements is selected.

The ID of an optional template to be used for selecting elements.

Map of variable binding indexed by identifying gt-code of the variable.

Predicates (constraints) that need to be satisfied before rule execution can occur. Generally speaking, predicates are constraints on variable values, and can only mention gt-codes of variables.

Marker to indicate whether variable is an input or output variable in the data-set. The value can either be:

The binding between a specific node in an archetype and a variable in the guide.

The gt-code of this element.

The path within archetype to reach this element.

Definition of structure for reporting guideline execution results.

The gt-code of this output template.

Name of this template.

Identifier of a model that defines the structure of the object.

The identifier of a template based on the model identified by model_id defining the attached object.

Detailed output report structure as an object that may be defined by a published model.

Abstract parent of all valued elements that may be used as a term in an expression. Concrete descendant types are generated by a GDL2 parser when processing a GDL2 text.

The function type() returns a value for the type of any concrete element, which may have been inferred and stored during parsing (Constants and Variables), or may be looked up (library of function calls).

Type name of the item. Comparisons should be done case-insensitive.

Abstract model of an operator-based expression.

The operator type of this expression.

Concrete model of a unary operator in the rule.

The operand.

Concrete model of a binary operator in the rule.

Left operand.

Right operand.

Enumeration of operator types.

Addition ('+') operation.

Subtraction ('-') operation.

Multiplication ('*') operation.

Division ('/') operation.

Exponent ('^') operation.

Logical and ('&&') operation.

Logical or ('||') operation.

Logical negation ('!') operation.

Relational equality ('==') operation.

Relational inequality ('!=') operation.

Relational less-than ('<') operation.

Relational greater-than ('>') operation.

Relational less-than-or-equal ('<=') operation.

Relational greater-than-or-equal ('>=') operation.

Subsumption operator ('is_a').

Negated subsumption operator ('!is_a').

Universal quantifier operator ('∀').

Concrete expression in the form of a function.

Function arguments.

The specific function.

Enumeration of function types.

Returns the absolute value of a double value.

Returns the smallest double value that is greater than or equal to the argument and is equal to a mathematical integer.

Returns Euler’s number e raised to the power of a double value.

Returns the largest double value that is less than or equal to the argument and is equal to a mathematical integer.

Returns the natural logarithm (base e) of a double value.

Returns the base 10 logarithm of a double value.

Returns the natural logarithm of the sum of the argument and 1.

Returns the closest long to the argument, with ties rounding to positive infinity.

Returns the correctly rounded positive square root of a double value.

Returns the trigonometric sine of an angle.

Returns the trigonometric cosine of an angle.

Maximum value of N elements.

Minimum value of N elements.

Count of instances of an element.

Total sum of N element values.

Terminal expression element representing a constant; subtypes define constants of specific types.

Symbolic name of constant.

Value of constant, redefined to specific types in descendants.

Constant of type String.

Value of constant, redefined to specific types in descendants.

Constant of type Integer.

Value of constant, redefined to specific types in descendants.

Value of constant, redefined to specific types in descendants.

Constant of type Date/time.

Value of constant, redefined to specific types in descendants.

Constant of type Code phrase.

Value of constant, redefined to specific types in descendants.

Constant of type Coded text.

Value of constant, redefined to specific types in descendants.

Constant of type Ordinal.

Value of constant, redefined to specific types in descendants.

Constant of type Quantity.

Value of constant, redefined to specific types in descendants.

Terminal expression element representing a named variable with a definition provided by the code attribute, containing a gt-code.

Variable symbolic name.

Internal gt-code defining the meaning of this variable.

Abstract concept of a statement, which is a self-standing procedural element.

A statement assigning an expression result to a variable.

Variable that is the target of the assignment.

Expression that is the source of the assignment.

A statement of the logical form assert(cond) that asserts the truth of a Boolean expression, which if not true, generates an exception at runtime.

Expression that is the subject of the assertion.

Inv_expression_type: expression.type().is_case_insensitive_equal('Boolean')

Local terminology of an archetype. This class defines the semantics of the terminology of an archetype.

Indicates whether this terminology is differential with respect to a specialisation parent, or complete.

Original language of the terminology, as set at creation or parsing time; must be a code in the ISO 639-1 2 character language code-set.

Term code defining the meaning of the artefact as a whole, and always used as the at-code on the root node of the archetype. Must be defined in the term_definitions property.

Directory of term definitions as a two-level table. The outer hash keys are language codes, e.g. "en", "de", while the inner hash keys are term codes, e.g. "gt17".

Directory of bindings to external terminology codes and value sets, as a two-level table. The outer hash keys are terminology ids, e.g. "SNOMED_CT", and the inner hash keys are constraint codes, e.g. "at4", "ac13" or paths. The indexed DV_URI objects represent references to externally defined resources, either terms, ontology concepts, or terminology subsets / ref-sets.

Specialisation depth of this artefact. Unspecialised artefacts have depth 0, with each additional level of specialisation adding 1 to the specialisation_depth.

True if language a_lang is present in archetype terminology.

True if there are bindings to terminology a_terminology_id present. True if terminology `a_terminology' is present in archetype ontology.

True if code a_code defined in this terminology.

Term definition for a code, in a specified language.

Binding of constraint corresponding to a_code in target external terminology a_terminology_id, as a string, which is usually a formal query expression.

List of terminologies to which term or constraint bindings exist in this terminology, computed from bindings.

List of languages in which terms in this terminology are available.

Original_language_validity: code_set (Code_set_id_languages).has_concept_id (original_language)

concept_code_validity: id_codes.has (concept_code)

Term_bindings_validity: bindings /= void implies not bindings.is_empty

Parent_archetype_valid: parent_archetype.terminology = Current

Representation of any coded entity (term or constraint) in the artefact terminology.

Code of this term.

Short term text, typically for display.

Full description text.

Hash of keys and corresponding values for other items in a term, e.g. provenance. Hash of keys ("text", "description" etc) and corresponding values.

One binding between a local gt-code and one or more external bindings

List of external codes, typically parsed in either URI form or openEHR standard form namespace '::' code.

Local gt-code to which external terms are bound.