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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valueofthetable,ifany,isdiscarded. Theoperationnewcreatesaninitializedbutemptytable.Theprevious literalisanorderedtableofenumerationorbooleanvalues.Eachcharacter StringLiteral Astringliteralisaself-deningcharacterstringvalue.Thetypeofastring 11.<strong>Hermes</strong>Operations109<br />
Concatenate denedasorderedtableofBit. stringofatypewhichincludesvaluesnamed'0'<strong>and</strong>'1'|e.g.atype theenumerationorbooleantype. inthestringliteralmustcorrespondtoasingle-characternamedliteralof Soif"0011010"isusedasastringliteral,itsresolvedtypemustbea<br />
Thisoperationconcatenatestwoorderedtablestoproducearesultcontainingacopyoftheelementsoftheleftoper<strong>and</strong>followedbyacopyofthe<br />
Selector elementsoftherightoper<strong>and</strong>.Theelementsmustbecopyable. concat::=term<br />
selector::=base{variableintable{variable ::=concatjterm<br />
simplyabbreviationsforlongselectors. threesyntacticformspermittedbythesyntax.Therstformiscalled Theselectorisasyntacticconstructusedinseveraloperations.Thereare alongselector,theothersmappingselectors.Themappingselectorsare ::=table{variable[[expression[,expression]...]]<br />
where(selector{expression)<br />
inaselectoriscalledanelementdeclaration.Itdenesanewvariablename Thevariablename(tablevariable)isthenameofatable.Thebasevariable<br />
Thisvariablenameisvisiblewithinthewhereexpression.Theexpression iscalledtheselectorexpression.Itevaluatestoaresultwhichisinferred calledtheelementvariable,whosetypeistheelementtypeofthattable. table.Theelementvariableissetequaltoaconstantcopyoftheelement. Theelementsforwhichtheselectorexpressionaretruearesaidtobe tobeoftypepredefined!boolean. selected. selectors.Ifthemappinglistisempty,thenallelementsareselected|itis Atexecutiontime,theselectorisevaluatedonceforeachelementinthe Amappingselectorisashorth<strong>and</strong>representingsomecommonusesof
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