5.1 Brief Syntax (Normative)

The following ABNF definition specifies the Brief Syntax of the SNOMED CT Expression Constraint Language.

expressionConstraint = ws ( refinedExpressionConstraint / compoundExpressionConstraint / dottedExpressionConstraint / subExpressionConstraint ) ws

refinedExpressionConstraint = simpleExpressionConstraint ws ":" ws eclRefinement

compoundExpressionConstraint = conjunctionExpressionConstraint / disjunctionExpressionConstraint / exclusionExpressionConstraint

conjunctionExpressionConstraint = subExpressionConstraint 1*(ws conjunction ws subExpressionConstraint)

disjunctionExpressionConstraint = subExpressionConstraint 1*(ws disjunction ws subExpressionConstraint)

exclusionExpressionConstraint = subExpressionConstraint ws exclusion ws subExpressionConstraint

dottedExpressionConstraint = subExpressionConstraint 1*(ws dot ws [attributeOperator ws] eclAttributeName)

subExpressionConstraint = [constraintOperator ws] [memberOf ws] (eclFocusConcept / "(" ws expressionConstraint ws ")")

simpleExpressionConstraint = [constraintOperator ws] [memberOf ws] eclFocusConcept

eclFocusConcept = conceptReference / wildCard

dot = "."

memberOf = "^"

conceptReference = conceptId [ws "|" ws term ws "|"]

conceptId = sctId

term = 1*nonwsNonPipe *( 1*SP 1*nonwsNonPipe )

wildCard = "*"

constraintOperator = childOf / descendantOrSelfOf / descendantOf / parentOf / ancestorOrSelfOf / ancestorOf

descendantOf = "<"

descendantOrSelfOf = "<<"

childOf = "<!"

ancestorOf = ">"

ancestorOrSelfOf = ">>"

parentOf = ">!"

conjunction = (("a"/"A") ("n"/"N") ("d"/"D") mws) / ","

disjunction = ("o"/"O") ("r"/"R") mws

exclusion = ("m"/"M") ("i"/"I") ("n"/"N") ("u"/"U") ("s"/"S") mws

eclRefinement = subRefinement ws [conjunctionRefinementSet / disjunctionRefinementSet]

conjunctionRefinementSet = 1*(ws conjunction ws subRefinement)

disjunctionRefinementSet = 1*(ws disjunction ws subRefinement)

subRefinement = eclAttributeSet / eclAttributeGroup / "(" ws eclRefinement ws ")"

eclAttributeSet = subAttributeSet ws [conjunctionAttributeSet / disjunctionAttributeSet]

conjunctionAttributeSet = 1*(ws conjunction ws subAttributeSet)

disjunctionAttributeSet = 1*(ws disjunction ws subAttributeSet)

subAttributeSet = eclAttribute / "(" ws eclAttributeSet ws ")"

eclAttributeGroup = ["[" cardinality "]" ws] "{" ws eclAttributeSet ws "}"

eclAttribute = ["[" cardinality "]" ws] [reverseFlag ws] [attributeOperator ws] eclAttributeName ws (expressionComparisonOperator ws subExpressionConstraint / numericComparisonOperator ws "#" numericValue / stringComparisonOperator ws QM stringValue QM)

cardinality = minValue to maxValue

minValue = nonNegativeIntegerValue

to = ".."

maxValue = nonNegativeIntegerValue / many

many = "*"

reverseFlag = "R"

attributeOperator = descendantOrSelfOf / descendantOf

eclAttributeName = conceptReference / wildCard

expressionComparisonOperator = "=" / "!="

numericComparisonOperator = "=" / "!=" / "<=" / "<" / ">=" / ">"

stringComparisonOperator = "=" / "!="

numericValue = ["-"/"+"] (decimalValue / integerValue)

stringValue = 1*(anyNonEscapedChar / escapedChar)

integerValue =  digitNonZero *digit / zero

decimalValue = integerValue "." 1*digit

nonNegativeIntegerValue = (digitNonZero *digit ) / zero

sctId = digitNonZero 5*17( digit )

ws = *( SP / HTAB / CR / LF / comment ) ; optional white space

mws = 1*( SP / HTAB / CR / LF / comment ) ; mandatory white space

comment = "/*" *(nonStarChar / starWithNonFSlash) "*/"

nonStarChar = SP / HTAB / CR / LF / %x21-29 / %x2B-7E /UTF8-2 / UTF8-3 / UTF8-4

starWithNonFSlash = %x2A nonFSlash

nonFSlash = SP / HTAB / CR / LF / %x21-2E / %x30-7E /UTF8-2 / UTF8-3 / UTF8-4

SP = %x20 ; space

HTAB = %x09 ; tab

CR = %x0D ; carriage return

LF = %x0A ; line feed

QM = %x22 ; quotation mark

BS = %x5C ; back slash

digit = %x30-39

zero = %x30

digitNonZero = %x31-39

nonwsNonPipe = %x21-7B / %x7D-7E / UTF8-2 / UTF8-3 / UTF8-4

anyNonEscapedChar = SP / HTAB / CR / LF / %x20-21 / %x23-5B / %x5D-7E / UTF8-2 / UTF8-3 / UTF8-4

escapedChar = BS QM / BS BS

UTF8-2 = %xC2-DF UTF8-tail

UTF8-3 = %xE0 %xA0-BF UTF8-tail / %xE1-EC 2( UTF8-tail ) / %xED %x80-9F UTF8-tail / %xEE-EF 2( UTF8-tail )

UTF8-4 = %xF0 %x90-BF 2( UTF8-tail ) / %xF1-F3 3( UTF8-tail ) / %xF4 %x80-8F 2( UTF8-tail )

UTF8-tail = %x80-BF