Contents of ABBREV

Abbreviations are possible only when `abbrev' mode is enabled. It can be toggled on and off on a buffer by buffer basis using the `abbrev_mode' command. If it is on, the word `abbrev' will appear on the status line.

Each buffer can have its own abbreviation table or use the ``Global'' abbreviation table. If a table has not been defined for a given buffer, the ``Global'' table will be used. Typically, abbreviation tables are mode dependent and are usually assigned to the buffer when a mode is selected.

An abbreviation table consists of abbreviations as well as a definition of characters that are allowed to appear in an abbreviation. By default, the characters that comprise a word are used. However, this is not always what is desired. For example, one might like to use abbreviations like `' for `

'inTeXmode.Forthistohappen, the`´charactershouldbeincludedinthedefinitionofaword.Theexamplesbelowshouldshedmorelightonthisconcept.

UsingAbbreviations = = = = = = = = = = = = = = = = = = =

Onceabbreviationshavebeenloadedintotheeditor(themechanismisexplainedbelow), theycanbeusedonlyifabbrevmodeisturnedon.Thismodecanbeturnedonoroffbypressing`ESCX'andentering`abbrev_mode'attheprompt.Itcanalsobeturnedoninamodehook.

Afterenteringanabbreviationintothebuffer, theabbreviationwillbeexpandedifthenextcharacterinsertedintothebufferimmediatelyafterthepositionoftheabbreviationisNOTamemberofthesetofcharactersthatisallowedinanabbreviation.ThentheeditorscansbackwardacrossthetextuntilitfindsacharacterthatisNOTpartofthesetofspecialcharacters.Finallyitattemptstoexpandtheresultingabbreviation.

Forexample, consideranabbreviationforTeXmodeandassumethat, whentheabbreviationtablewascreated, thecharacters`,́`a - z',`A - Z', and`0 - 9'werespecifiedasthespecialsetofcharactersthatmaybeusedinanabbreviation.Thismeansthat` $\displaystyle \be{^\prime}$ isavalidabbreviationbut`@be'isnotsince`@'isnotpartoftheaboveset.Supposethat` $\displaystyle \be{^\prime}$ istheabbreviationfor`

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'and` $\displaystyle \be{^\prime}$ isenteredonalineas

Thisisanequation. $\displaystyle \be$

Atthispointnothinghappens.However, ifaSPACEisinserted, theeditorwillrealizethatthespaceisnotpartofthespecialabbreviationcharactersetandscanbackuntilanothercharacterNOTinthesetisfound.Inthiscase, itwillfinda`.'.Fromthisinformation, itlooksup` $\displaystyle \be{^\prime}$ inthetable, finds`

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'andexpandsthelinetolooklike :

Thisisanequation.

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However, ifthelinehadlookedlike :

Thisisanequation $\displaystyle \be$

theexpansionwouldhavefailedbecausetheeditorwouldhavescannedbacktothespacecharacterbetween`an'and`equation'andtriedtoexpand`equation $\displaystyle \be{^\prime}$ .

Althoughthissoundscomplex, itistrivialinpractice.

TheAbbreviationFile = = = = = = = = = = = = = = = = = = = = = =

AnabbreviationfileissimplyafilethatcontainstheapproriteS - Langfunctioncallstocreateabbreviationtablesandassignabbreviationstothetables.ItisloadedlikeanyotherS - Langfile, via`evalfile'.Simplyturningabbreviationsonvia`abbrev_mode'issufficienttocauseJEDtoloadthefile.

Thevariable`Abbrev_File'maybeusedtospecifythenameoftheabbreviationfile.Ifthisvariableisundefined, thefilenamedefaultsto`abbrevs.sl'onnon - Unixsystemsand`.abbrevs.sl'onUnix.ItisassumedtoresideintheHOMEdirectory.Tospecifyadifferentname, e.g.,`/usr/lib/jed /abbrev.sl', put

variableAbbrev_File = "/usr/lib/jed /abbrev.sl";

intheJEDstartupfile.

HereisasimplefilethatissufficienttocreateaglobalabbreviationtableandalocaltableforTeXmode :

create_abbrev_table("Global","");define_abbrev("Global","adn","and");define_abbrev("Global","amy","amy.tch.harvard.edu");

create_abbrev_table("TeX","
A - Za - z0 - 9");define_abbrev("TeX","
be","
beginequation");define_abbrev("TeX","
ee","
endequation");

Notethat`create_abbrev_table'takes2parameters.Thefirstparameterissimplythenameofthetabletobecreatedandthesecondparameterrepresentsthelistofcharactersthatareallowedtobeinanabbreviation.Ifthesecondparameteristheemptystring, JED'sworddefinitionwillbeused.AlsonotethatthebackslashcharactermustbetypedtwiceforS - Langtointerpretitproperlyasabackslashcharacter.

The`define_abbrev'functiontakes3parameters : thenameofthetable, theabbreviation, andtheexpansionfortheabbreviation.

Thereisreallynothingspecialaboutanabbreviationfile.ThecodethatappearsinitcanalsoappearintheJEDstartupfile.

Usuallytheabbreviationmodeisenabledinahook.Forexample, toenableabbreviationsforTeXmode, useamodehookoftheform :

definetex_mode_hook()set_abbrev_mode(1);

Thisway, whenTeXmodeisenabled, theabbreviationfilewillbeautomaticallyloadedifnotalreadyloadedandabbrevmodewillbeturnedon.

CreatingAbbreviations = = = = = = = = = = = = = = = = = = = = = =

Therearetwowaystocreateabbreviations :

1.Simplycreateanabbreviationfilebyhand.2.Usethe`define_abbreviation'functioncall.

Herethelattermethodisexplained.

The`define_abbreviation'functionusestheabbreviationtableassociatedwiththecurrentbuffer.Ifthereisnoneexplicitlyassociatedwiththebuffer, theGlobaltablewillbeused.Ifthetabledoesnotexist, itwillbecreated.Thisfunctionwillpromptforanabbreviation.Itmayormaynotpromptforanexpansion.Ifaregionisdefinedwhen`define_abbreviation'iscalled, theregionwillbetakenastheexpansion.Thisisusefuliftheexpansionconsistsofofmorethanoneword.Ifaregionisnotdefined, theexpansionwillconsistofthepreviouswordasdefinedbythetable.Onlyifthatfailswilltheuserbepromptedforanexpansion, e.g., thiscouldhappenifthePointisatthebeginningofaline.

Notethatsimplyusing`define_abbreviation'byitselfdoesnotsavetheabbreviationforfutureuse.Tosavetheabbreviationstotheabbreviationfile, usethefunction`save_abbrevs'.Thatis, press`ESCX'andenter`save_abbrevs'attheprompt.Theeditorwillthenpromptforafilename.SimplyhittingRETURNatthepromptmeansthatthe`Abbrev_File'definitionwillbeused.Enteradifferentfilenametosavethemelsewhere.Notethatenteringanewfilenamewillnotchangethevalueof`Abbrev_File'.Also, thisfunctionsavesALLcurrentlydefinedabbreviationtables.

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