Hermes: A Tutorial and Reference Manual - Researcher - IBM
Hermes: A Tutorial and Reference Manual - Researcher - IBM
Hermes: A Tutorial and Reference Manual - Researcher - IBM
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10211.4.ScalarOperations eration.Youcancopynominals<strong>and</strong>testthemforequality.Youcannot uesareequaliftheyarecopiesofthesamegeneratedvalue,otherwisethey areunequal.Anominaltypedenitioncreatesanewnominaldomain. performorderedcomparisonsorconversionstointegers.Twonominalval-<br />
anamedliteralwitheachvalue,e.g.'blue'.Thenamedliteralsofasingle enumerationtypedenitionmustbedistinct.Thisnamedliteralcanbe merationtypedenitiondenesanewenumerationdomain,<strong>and</strong>associates Example:::=nominal TransactionId:nominal; Anenumerationdomainconsistsofanitenumberofvalues.Anenu-<br />
type{construction<br />
usedinexpressionstogeneratethevalueitnames.Enumerationvaluesof course,thevalue'blue'inoneenumerationdomainhasnothingtodo withthevalue'blue'inadierentenumerationdomain,sinceonlyvalues thesametypeareequaliftheyareequaltothesamenamedliteral.Of ofthesametypecanbecompared. type{construction<br />
thekeywordorderedappearsinthedenition.Unorderedenumerations ::=[ordered]enumeration(<br />
supportcomparisonsonlyforequality<strong>and</strong>inequality,justlikenominals. Enumerationsareeitherorderedorunordered,dependingonwhether ::=variantofenumeration{type( )<br />
[case{declaration[,case{declaration]...] [named{literal[,named{literal]...]<br />
Orderedenumerationsalsosupporttheorderedcomparisons,=.Theyalsocanbeconvertedtointegers.Therstenumerationliteral Thefollowingaresomeexamples.<br />
theother\false".Abooleantypedenitionassociatesthetrue<strong>and</strong>false valueswithdistinctnamedliterals. thatcontainsallthecharactersoftheASCIIcharactersetinsortedorder. Aboole<strong>and</strong>omainconsistsoftwovalues,onerepresenting\true"<strong>and</strong> option:enumeration('present','absent'); color:enumeration('red','blue','yellow','green'); ThereisapredenedorderedenumerationtypecalledPredefined!Character quality:orderedenumeration('poor','fair','good','excellent'); type{construction ::=boolean(boolean{association)
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