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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ationtable[expr].Wehaveencounteredthisabbreviationintheprogram positioninthetableisexpr."Thisformofselectorworksexactlylikearray indexing.Itissocommonthat<strong>Hermes</strong>allowsyoutousetheabbrevi-<br />
where(positionofelement=expr)means\selecttheelementwhose BoundedBuffer.ThestatementremovecmdfromLine[0]isashorth<strong>and</strong> 422.6.TokenizerProcedure<br />
\removetherstcharacterfromLine<strong>and</strong>storeitincmd." theelementbeingtestedbytheselector.Forexample,elementintable<br />
aspartofanotheroperator:e.g.remove,every,extract,position: forremovecmdfromCinLinewhere(positionofC=0),<strong>and</strong>itmeans Aselectorcanappeareitherbyitselfasanexpression,oritcanappear Aselectorallbyitselfinanexpressionreturnsacopyoftheselected thentheearliestoneischosenifthetableisordered,<strong>and</strong>anarbitrary oneischosenifthetableisunordered.ANotFoundexceptionisraised ifthereisnoselectedelement.Example:Line[0]evaluatestotherst characterofLine,ifLineisnon-empty,otherwiseitraisesaNotFound thenamethe-element.Ifthereismorethanoneselectedelement, exception.ItcanalsobewrittenCinLinewhere(positionofC =0). element.Youcanlookthisoperationupinthereferencemanualunder<br />
Theeveryofoperationgeneratesanewtableconsistingofevery Theremovestatementremovesasingleelement.Ifnoelementis selected,therstselectedelementischosenifthetableisordered, selected,aNotFoundexceptionisraised.Ifmorethanoneelementis otherwiseanarbitrarychoiceismade.<br />
Theextractstatementissimilartoeveryof,exceptthatitremoves wherethisoperationwasusedtoselectthosecharactersbefore<strong>and</strong> computesubsetsorsubstrings.(ReferbacktotheprogramCompound, elementswillhavethesamerelativeorder.Thisoperationisusedto selectedelement.Iftheoriginaltablewasordered,thetableofselected afterthe'/'.<br />
ble,<strong>and</strong>thepositionofoperatordiscussedabove,whichisappliedwithin Notethedierencebetweenpositionofselector,whichsearchesata-<br />
Thepositionofoperationwithaselector(e.g.positionofCin aNotFoundexceptionisgenerated. Linewhere(C=':'))returnsthepositionoftherstselectedelementwithintheorderedtable.Ifnoelementinthetableisselected,<br />
theelements. theselectedelementsfromitssourceoper<strong>and</strong>,ratherthancopying<br />
=':').ThisexpressionsearchesfortherstcoloninLineafterposition P,<strong>and</strong>returnsthepositionofthatcolon. aselectorpredicate.Thefollowingexpressionusesbothkindsofposition ofoperators:positionofCinLinewhere(positionofC>P<strong>and</strong>C
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