The Screen Control Language (SCl) in Version 6 SAS/Ar: and SAS/FSp Software Chris Bailey, Yao Chen SAS Institute Inc., Cary, NC

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1 The Sceen Contol Language (SCl) in Vesion 6 SAS/A: and SAS/FSp Softwae Chis Bailey, Yao Chen SAS Institute Inc., Cay, NC Abstact Explanations and examples povide the basis of this tutoial that explains the new sceen contol language available in Vesion 6 SAS! AF and SASjFSP softwae. The sceen contol language povides the ability to develop inteactive applications. The functions available in the Sel povide the basis fo developing convesational systems fo end uses. Examples will be used to demonstate how the language woks. Diffeences in Sel usage in SAS/FSP applications and SAS/AF applications will also be demonstated though examples. Similaities and diffeences between the SAS Data Step and the sceen contol language will also be emphasized. Contents 1. Requiement analysis 2. Design 3. Compaison vs Data Step Language 4. Pogamming Constucts and featues 5. Pogamming Concepts 6. SAS Data Set Inteface 7. Examples 8. Futue Requiements Analysis Fo SAS/FSP softwae, one item of moe functionality equested on the SASWARE ballot is coss-field validation in PROC FSEO IT. We win show you how this is done with vesion 6 and povide examples. In addition to PROC FSEDIT, we will achieve the same functionality with vesion 6 SAS/AF, now integated with the sceen contol language (SCL), eliminating the estictions of the Vesion 5 symbolic language(## and ###). We will also cove estictions of the data step and how much of this is cicumvented in vesion 6. tn addition to functionality vesion 5 lacked, vesion 6 also had a few of its own poblems: namely unning on a much smalle and much slowe machine. Thee must be good keystoke esponse duing execution. The Execution State (unning compiled code, moe on this late) must be potable to all machines (not even an issue in vesion 5) Design The design algoithm used to achieve the speed and size necessay to un well as well as incopoation of much moe extended and extendable functionality: Rst, PROC FSEDIT and AF wok like the pogammable data step, whee each time the use changes the sceen, this is a new tansaction ecod to be pocessed, and contol is given to the use to pocess the data. Second, the manne in which the use pocesses the data is though the pogamming language SCL Thid, the use's SCl statements ae handled in two diffeent phases: 1. The compile phase duing PRCe BUILD o PRCe FSEDIT sceen modifica tion, 2. the execution phase duing AF (which was PROC DIS PLAY in vesion 5) and data set editing in vesion 6. This diffeentiation of compile-time and execution-time enables AF and PROC FSEDIT to move much of the pocessing to set-up o compile-time so execution just pefoms tasks equested with as little ovehead as possible. Making execution time come at any numbe of abitay points late entails saving and poting com~ piled code which is done in vesion 6. Compaison vs Data Step In compaison to the data step, a tansaction ecod is the sceen afte the use stikes an attention key, whee in the data step a tansaction ecod is the next line of input fom a file o the next obsevation fom a setfo anothe data set. Vaiables ae impiicn itly etained in SCl, whee they ae not etained unless explicitly equested in the data step. Moe timing contol is given to the SCl pogamme though eseved labels, which ae stated at pedefined times. labels that contol the Sel monito timing, and thei paallel in the Data Step: sel FSEINIT: INIT: MAIN: TERM: FSETERM: Data Step Data Step stated Any obsevation stated Cuent obsevation modified Finish the cuent obsevation Data step finished The syntax is the same as the data step, using constucts and featues like declaation statements, assignment statements, conditional statements, and do-end blocks. Pogamming constucts and featues 1. Conditional statement 2. Reseved labels 3. SUBMIT 4. Field modification statements/functions 5. Window functions a.af b.fsp c. Display fomat infomation d. Selection list window e. PREVIEW window 6. Data Set Functions (see Data Set Inteface below) 7. File functions 8. Fomat functions a.input b.put 1155

2 9. Maco functions a.symget b. SYMPUT 10. Extended tables 11. Command line 12. LEAVE and CONTINUE fom DO block 13. CONTROL statement to altenate monito timing By default, contol is given to the pogam wheneve a sceen data modification occus that does not cause an eo state. Howeve, we, as the sceen builde, can get contol moe fequently; like evey time an 'attention' key is pessed by equesting SCL to dive ou MAIN: labels moe fequently. 14. Run-Time binding. With the delayed execution o savings of compiled code, thee is no compile-time binding to data sets, and many of the functions have un-time vaiable aguments; such as put, input. and open. 15. "'ays a. Opeatos (=, IN) b. Function that accept of lists (mino, maxo) c. Binding with functions like SET, Pogamming Concepts Pogam Unit OS Veification Maintainability Infomation hiding Recusion In Vesion 6, pogam sceens, and even FSEOIT sessions can be teated as a suboutine. Though the CALL DISPLAY and CALL FSEDIT statements in SCL, we can banch to these objects, each of which have thei own pogam code, and wait fo them to etun afte setting up any global infomation we depended on them fo. Fom AF pogam sceen enty 'one.pogam' we can CALL DISPLAY('lwo.pogam'); and 'one.pogam' teats this in the same fashion an abso function takes, just sequential execution of the pogam. We can use data sets to veify the sceens. we can now bind the cuent sceen to any numbe of data sets in any fashion by doing ou own data set manipulation within the pogam souce. The list objects o lists of values that data enteed is veified against can now come fom a data set, and be moe dynamic. the data set seach can be a linea o binay seach depending on how the LOCATE function is invoked. Now the sceen can much moe easily be boken up into smalle simple units with fewe 'duties' each. This beakup means the sceens ae easie fo the end-use to undestand, and should be much easie fo the builde to maintain. Each sceen can display as much infomation as necessay to the use but only popagate items pevious and successive sceens need. Since each Sel pogam is an independent eentant enty object, it can call anything, even anothe instance of itself via the Call DISPLAY and Call FSEDIT functions. DynamiC SAS Data Set Inteface OPEN/CLOSE VB! InfolDS Info Obs Fetch/Update Vax Get/Put SET LOCATE Examples that follow 1. Value validation 2. Coss field validation We can make the pogams un based on setup that comes fom the sceen, In Vesion 5, INPUT and VARLISTfield attibutes ae an example of checking one field that is based on anothe. Now we can take this much futhe by using any logic on any field and having any pogammable elationship on any othe. The actual data set that the sceen needs does not have to be known at compile time. Simply leave a vaiable name and whateve that value is will be used as one of the data sets to be used. We can easily quey any infomation need. ed about the data set o its vaiables though the handle etuned fom open. We can fetch, update, append obsevations though explicit pogam conta\. When we have an obsevation, we If we ae using the data set fo etieval, we fetch the obsevation and then quey the vaiables of inteest Afte we decide on a data set, we can bind the data set vaiables to the pogam vai. abies so an obsevation fetch o update will use the values of the pogam vaiables. This is Run-Time binding of a sceen to a data set If we want to do list validation lookup, we can do this on any of the data sets we have opened, against any vaiable in them, in ei the linea o binay fashion by specifying paametes to LOCATE. Some pogams cuently using SCL Futue 1. Vesion 6.03 menu system 2. Vesion 6,04 futue diections system 3. Full sceen confidence inteval 4. Full sceen poject management 1. Inteface with Data Step functions 2. Inteface between the sceens - Paamete passing to eplace symgetjsymput 3. Debugging ability - Souce Language Debugge 4. Sevices window 5. Optional dopping of command and message line 6. A? to display selection lists 7. Submit fom AF to go to appopiate window and etun 8. Appointment calenda 9. Calculato 1156

3 10. Single selection choice goups 11. Switches 12. Multiple selection choice goups 13. New functions fo: Examples Cuso positioning Selection Blocks Data Set modification and definition Flat file handling SAS Option quey and set Use pogammable selection lists Moe default builtin selection lists Examples using SCl ae on following pages. Pogamming Hints, Debugging EMS is highly ecommended; without it, AF can go away in ode to satisfy memoy needs of the pocedue. tf you need you pogam sceen to continue execution instead of etuning fo inteactive i/o afte a submit, use submit continue. Conclusion With the stuctue and powe of the language, we can make ou sceens do nealy anything pogammable and still have good esponse time at the teminal. Acknowledgements The authos wish to thank Deva Kuma fo his guidance in developing SCl, and Bud Whitmeye and Bian Schellenbege fo thei aid in typesetting the pape. 8ase SAS, SAS/Af, and SAS/FSJ> ae egisteed tademaks of SAS Institute Inc., Cay, NC. 1157

4 The Sceen Contol Language (SCl) in Vesion 6 SASjAF and SASjFSp Softwae Example 1 Value validation fom a list Poblem Given a finite list of of known size and known values, validate the use's enty against the list. Solution Put the values into a pogam aay, and seach the aay evey time the use modifies the value. The pogam calls the link label indxlkup, which is expected to etun the index in the aay of the element that equals value fom the sceen. The link label ptesult sets the value of the message line to indicate whethe o not the value is valid based on the index. Sceen Command = = = > '456' is illegal, Please eente. Pogam Model Please Ente Data Value: 456 aay goodvals(20) ( 1298, 2598, 3465, 4565, 5465, 6787,7523,8234,9734, 10732, 11231, 12634, 13762, 14324, 15634, 16347,17324,18492,19988,20117 ); aay petty[o:i) $ 25 ( 'ok', 'illegal, Please eente.'); init: main: link indxlkup; link ptesult; tem: ptesult: note the tick of using the odinal value of the 'index -= 0' compaison as the aay index 'f _ msg_ == putn(value,'bests.') II' is ' /1 petty{index -= 0]; Method 1. Staight linea seach of the aay. Values do not have to be soted. do j = 1 to dim(goodvals); if goodvalsu] = value then index = j; Method 2. Binay seach of the aay. Values must be soted. hi = dim(goodvals); 10 -= 1; mt = 1; do while(lo < = hi); mi = int«lo + hi) f 2 ); if value < goodvals[ mil then hi=mi-l; else ifvatue -= goodvals[mi] then index = mi; else lo=mi+1; Method 3. - Best Solution Use the IN opeato. index = value in goodvals; Altenate Solution An altenate solution that equies no pogamming in the AF o FSEDIT enty is to use SAS Fomats and Infomats. f' sets the vaiable INDEX to indicate location of matching value, fill in fom any of fouowing methods. 'f 1158

5 The Sceen Contol Language (SCl) in Vesion 6 SASjA= and SASjFSp Softwae Example 2 Value validation fom a SAS Data Set Poblem We need to validate use's enty against a list of values that may only be known immediately pio to execution of the sceen, and can change between invocations. The values ae not of known dimension and value at compile-time. Solution Maintain the values in a SAS Data Set, which we can update at any time. We apply much of the same technique to validating against the SAS Data Set that we used fo an aay. The sceen is the same as the pevious example. Pogam Model init: get a handle on the data set we ae to seach against fo the compaison values *j dsid = open('valud.ata'); if dsid = 0 then _ msg_ = 'Unable to open the data set'; vnun = vanum(dsid,'somevnan'): if vnun = 0 then _nsg_ = 'Vaiable not in data set'; main: link indxlkup; link ptesult; tem: /' cleanup, fee memoy, elease the data set *j call close( dsid); ptesult: _ msg_ = putn(value, 'bests.') II ' is' II pettylindex = 01; sets the vaiable INDEX to indicate location of matching value, fill in fom any of following methods. *j Method 1. Staight linea seach of the data set. Values do not have to be soted. do i = 1 to nobs( dsid); if fetchobs( dsid,i) = 0 then if getvan(dsid,vnum) = value then index = i; Method 2. Binay seach of the data set. Values must be soted. hi = nobs( dsid); 10 = 1; mi = 1; do white(lo < = hi); mi = int«lo + hi)j2); iffetchobs(dsid,mi) "'= 0 then _ msg_ = 'Unable to etieve obsevation'; stop; dsval = getvan(dsid,vnum); if value < dsval then hi = mi-l; else if value = dsval then index = oi; else lo=mi+l; Method 3 ~ Best Solution with unsoted data. Use the builtin function LOCATE. index = locaten(dsid,vnum,value)j Method 4 ~ Best Solution with soted data. Use the builtin function LOCATE. index = locaten(dsid,vnum,value,'ascending'); 1159

6 The Sceen Contol language (SCll in Vesion 6 SAS/A~ and SAS/FSp Softwae Example 3 Coss Field Validation Poblem Coss field Validation The laboatoy of XYZ hospital need a Lab Repot System fo thei data enty staff. The equiements of this lab Repot Sys. tem ae: Solution All invalid data and inconsistent data must be detected as soon as that data is enteed (inteactive). Handle two kinds of inconsistency eos: 1. A 'Rea eo. Fo example, a male patientwith a lab epot 'pegnant. I In this case, the end-use should eente the coect input data. 2. A 'Suspicious' eo. Fo example, an infant with a lab epot 'athitis.' In this case, the system should equest the end-use eithe to veify o to eente the data. Wite an SCL pogam behind an FSEDIT sceen that pefoms the validation whee each new epot is a new obsevation in the data set. Fo the fist kind of inconsistency eo, We use the SCL statements ERRORON and ERROROFF to flag the eo. Fo the second kind of inconsistency eo, we pop-up a veification field. We use the SCL statements PROTECT and UNPRD TECT. It will appea as if the question field is ceated as soon as it is needed. Sceen Command = = = > * x:z Hospital Lab Repot System * Patient Infomation: Name:&NAME Sex: &SEX_ P{Je: &AGE_ Diagnosis: &RESULT main: msg = 'Data is accepted'; dununy = _blank_; link: tunoff; if veify A = 'Y' then link checkit; else veify = _blank_; tem: tunoff: eooff all ; dummy ~ blank; potect veify; - etunj checkit: select (esult); when('pegnant') jo * a eal inconsistent eo OJ if sex = 'M' then eoon sex esult; cuso sex; _ msg_ = 'Eo: inconsistent values enteed'; suspicious inconsistent eos as defmed by the pogamme OJ when('diape ash') if age > 10 then link suspae; when('athitis') jf age < 15 then link suspae; othewise; Pogam &DUMMY init: _ msg_ = 'Please ente you data'; veify = blank; dummy ~ bladk; potect veify; - &VERIFY suspae: _ msg_ = 'Waning: Suspicious data. ' II 'It is extemely ae fo a ' II age II 'old peson to have' II esult II '. Veify o eente; eoon age esult; cuso veify; unpotect veify; dummy = 'Veify the inconsistent data (Y /N)'; 1160