; TeX output 1998.01.17:2004y?RDtGGcmr17The7tGGcmss17delaqrrayq:package!", cmsy10XQ cmr12DarvidCarlislepScarlisle@cs.man.ac.uk&37 1994/03/14:ōRNff cmbx121jLExamplesRK`y cmr10The=additionto cmmi10aCbc_dџ^qύaSimilarlyifanenvironmentequivqalentto- cmcsc10PlainTU>'ExX's\casescouldbGede nedRby:R\begin{array}\{{lL}.UU...8f(x)=^dG0=ÐifUUx=0Gsin8(x)=x=ÐotherwiseqύRHereBL2issuppGosedtodenoteacolumnofleftalignedL-Rtext.\ItmaybGede nedRvia:Q\newcolumntype{L}{>{$}l<{$}},:as?discussedinarray.sty.NotethatasRthedelimitersmustalwaysbGeusedinpairs,the`.'mustbGeusedtodenotea`nullRdelimiter'.aThisfeatureisespGeciallyusefulifthe[t]or[b]argumentsarealsoused.RInthesecasestheresultisnotequivqalenttosurroundingtheenvironmentbyR\left...\right,UUascanbGeseenfromthefollowingexample:-m0 m@\n1\n2\n3\o1 \oAZ0 @d123ZƇ1 ƇA0 @ޱIJ1ޱ2ޱ3ū1 AqDznotR:0:B:B:B:Bfi:@#N;1#N;2#N;3R-N<1-NmacrotestsforanoptionaldelimiterbGeforetheleftbraceofthemainpream-Rble7,argument.gIfthereisnodelimiter,=5\@arrayleftand\@arrayrightaremadeRano-ops,and\@arrayiscalledwiththepGositionalargument.cFOtherwisecallR\@del@array.Us4\\def\@@array[#1]{\@ifnextchar\bgroup Us5f{\let\@arrayleft\relax\let\@arrayright\relax\@array[#1]}%Us6f{\@del@array[#1]}}L\@del@arrayRW*eUUnowknowthatwehaveanarray(ortabular)withdelimiters.Us7\\def\@del@array[#1]#2#3#4{%RThefollowinglineiscompletelyredundantbutitdoGescatcherrorsinvolvingde- RlimitersbGeforetheprocessingofthealignmentbegins.%AcommonerrorislikelyRtoحbGeomitingthe`.'ina\cases-typeconstruction.Thiscausesthe rsttokenRof)nthealignmenttobGegobbled,26possiblycausinglotsofspuriouserrorsbeforetheRcauses|oftheerror,{themissingdelimiter,isdiscovereds|as\@arrayrightputstheRalignmentUUandthedelimiterstogether.Us8f\setbox\z@\hbox{$\left#2\right#4$}%RInҥthecaseofa`c'argumentwedonotneedtorebGoxthealignment,sowecanRde neUU\@arrayleftand\@arrayrightjusttoinsertthedelimiters.Us9f\if#1c\def\@arrayleft{\left#2}\def\@arrayright{\right#4}%ROtherwisewe(should)havea[t]or[b]argument,so rstwestorethealignment,RwithoutUUdelimitersinbGox0.R10f\else\def\@arrayleft{\setbox\z@}%RThenUUafterthealignmentis nished:R11f\def\@arrayright{%RCalculatetheamountthebGoxneedstobGelowered(thiswillbGenegativeinthe Rcaseh[of[b]).AhVlittlebitofarithmeticcf.theTU>'ExXBoGok,mAppendixh[G,rule8.W*eRcalculateKtheamountthisway*,M ratherthanjusttakingthedi erencebGetweentheRdepthofbGox0andthedepthoftheboxde nedbelow,̑asthedepthofthatbox2 y?Rmay?bGea ectedbythedelimitersif\delimitershortfallor\delimiterfactor RhaveUUnon-standardvqalues.R12tJ\dimen@=\dp\z@ R13tJ\advance\dimen@-\ht\z@R14tJ\divide\dimen@by\tw@R15tJ\advance\dimen@by\fontdimen22\textfont\tw@RNowUUlowerthealignmentandthedelimitersintoplace.R16tJ\lower\dimen@\hbox{$\left#2\vcenter{\unvbox\z@}\right#4$}}%REndUUthe\if#1cR17f\fiRNowUUthatwehavede ned\@arrayleftand\@arrayright,call\@array.R18f\@array[#1]{#3}}R19\h!5" cmmi9=pack9age#g i6R&N cmbx122.1pnewarray.styuTRAllthefeaturesoftheoldnewarraystyleoptionhavebGeenmergedintothearray RorUUdelarrayoptions.3;y&N cmbx12#ow cmss9" cmsy9!5" cmmi9ߤN cmtt9- cmcsc10 cmmi10K`y cmr10ٓRcmr7u cmex10