Documentation
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Overview ¶
Package expression provides functionality to process SNOMED CT expressions Expressions are usually multiple SNOMED CT concepts combined together, much like a sentence is made up of words.
SNOMED CT contains single concepts that actually represent expressions; these are usually historic or exist for ease of use. In order to appropriately determine equivalence, a range of functions are required to normalise any arbitrary concept or expression into a normalised form.
The ANTLR parser was generated from the original ABNF source file using http://www.robertpinchbeck.com/abnf_to_antlr/Default.aspx and running java -jar ~/Downloads/antlr-4.7.2-complete.jar -Dlanguage=Go -package ecl -o ecl ECL.g4 java -jar ~/Downloads/antlr-4.7.2-complete.jar -Dlanguage=Go -package cg -o cg CG.g4 The compositional grammar (CG) is from https://confluence.ihtsdotools.org/display/DOCSCG/5.1+Normative+Specification The expression constraint grammar (ECL) is from https://confluence.ihtsdotools.org/pages/viewpage.action?pageId=28739405
Index ¶
- func ApplyConstraint(svc *terminology.Svc, exp *snomed.Expression, s string) (bool, error)
- func CreateSimpleExpression(concept *snomed.Concept) *snomed.Expression
- func Equal(e1 *snomed.Expression, e2 *snomed.Expression) bool
- func Normalize(svc *terminology.Svc, e *snomed.Expression) (*snomed.Expression, error)
- func NormalizeConcept(svc *terminology.Svc, c *snomed.Concept) (*snomed.Expression, error)
- func Parse(s string) (*snomed.Expression, error)
- func Render(exp *snomed.Expression) string
- type Normalizer
- type ParseError
- type Renderer
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func ApplyConstraint ¶
func ApplyConstraint(svc *terminology.Svc, exp *snomed.Expression, s string) (bool, error)
ApplyConstraint applies an expression in the "Expression Constraint Language" (ECL) to the specified (CG) expression
func CreateSimpleExpression ¶
func CreateSimpleExpression(concept *snomed.Concept) *snomed.Expression
CreateSimpleExpression creates an expression from a single concept
func Equal ¶
func Equal(e1 *snomed.Expression, e2 *snomed.Expression) bool
Equal determines whether two expressions are exactly equal
func Normalize ¶
func Normalize(svc *terminology.Svc, e *snomed.Expression) (*snomed.Expression, error)
Normalize expands an expression into a normal-form, which makes it more readily computable. This essentially simplifies all terms as much as possible taking any complex compound single-form SNOMED codes and building the equivalent expression. Such an expression can then be used to determine equivalence or analytics. See https://confluence.ihtsdotools.org/display/DOCTSG/12.3.3+Building+Long+and+Short+Normal+Forms and https://confluence.ihtsdotools.org/display/DOCTSG/12.4+Transforming+Expressions+to+Normal+Forms
func NormalizeConcept ¶
func NormalizeConcept(svc *terminology.Svc, c *snomed.Concept) (*snomed.Expression, error)
NormalizeConcept turns a single concept into its primitive components
func Render ¶
func Render(exp *snomed.Expression) string
Render is a simple helper to render the specified expression using a default renderer.
Types ¶
type Normalizer ¶
type Normalizer struct {
// contains filtered or unexported fields
}
Normalizer handles normalization of SNOMED CT expressions in which we expand an expression into a normal-form, making it more readily computable. This essentially simplifies all terms as much as possible taking any complex compound single-form SNOMED codes and building the equivalent expression. Such an expression can then be used to determine equivalence or analytics. See https://confluence.ihtsdotools.org/display/DOCTSG/12.3.3+Building+Long+and+Short+Normal+Forms and https://confluence.ihtsdotools.org/display/DOCTSG/12.4+Transforming+Expressions+to+Normal+Forms
Any SNOMED CT expression can be transformed to its normal form by replacing each reference to a fully defined concept with a nested expression representing the definition of that concept. Transformation rules then resolve redundancies, which may arise from expanding fully defined concepts, by removing less specific attribute values.
The steps are: 1. Separate Information Model Context - https://confluence.ihtsdotools.org/display/DOCTSG/12.4.1+Separate+Information+Model+Context 2. Normalising the expression - https://confluence.ihtsdotools.org/display/DOCTSG/12.4.2+Normalize+Expression 3.
func NewNormalizer ¶
func NewNormalizer(svc *terminology.Svc) *Normalizer
NewNormalizer creates a new normalizer for the given expression
func (*Normalizer) Normalize ¶
func (n *Normalizer) Normalize(e *snomed.Expression) (*snomed.Expression, error)
Normalize normalizes the specified expression
type ParseError ¶
ParseError returns information about a parsing error
func (*ParseError) Error ¶
func (pe *ParseError) Error() string
type Renderer ¶
type Renderer struct {
// contains filtered or unexported fields
}
Renderer renders a SNOMED CT expression as text such that it can be roundtripped back to an expression via parsing. This means that generated text meets the syntax in the compositional grammar.
func NewCanonicalRenderer ¶
func NewCanonicalRenderer() *Renderer
NewCanonicalRenderer returns a renderer that formats expressions canonically. This adopts the rules outlined here: https://confluence.ihtsdotools.org/display/DOCTSG/12.4.29+Canonical+Representation
func NewDefaultRenderer ¶
func NewDefaultRenderer() *Renderer
NewDefaultRenderer returns a renderer with the default formatting options
func NewUpdatingRenderer ¶
func NewUpdatingRenderer(svc *terminology.Svc, tags []language.Tag) *Renderer
NewUpdatingRenderer returns a renderer that updates terms according to the preferred synonyms
Source Files
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