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SCL for Base SAS ProgrammersSCL for Base SAS Programmers

Why and How

Jerry Le Breton

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AgendaAgenda

This is NOT a tutorial on SCL

What isSCL?

Why you oughtto know

How to mix BaseSAS and SCL

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SCL FeaturesSCL Features

Supports on-line applications

Object oriented language

- forcode re-use in class libraries

Extra coding features and functions

Dynamic arrays

SCLLists

Otherextra functionality

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SCL Invades the Data StepSCL Invades the Data Step

In 6.12 theSCLI/O functions were included in BaseSAS

Data Step:data _null_;

set logs end=theend;

if fileextn='txt' then

txt + 1;if theend then put txt=;

But

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SCL Invades the Data Step (2)SCL Invades the Data Step (2)

EquivalentSCLcode:dsid=open(logs');

call set(dsid);do while (fetch(dsid)=0);

if fileextn='txt' then

txt + 1;end;

rc = close(dsid);

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SCL Invades the Data Step (3)SCL Invades the Data Step (3)

The previousSCL will run in an SCL program or

a Data Step

Faster as real SCL becausecompiled before

execution

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SCL ArraysSCL Arrays

SCLsupports,standard,static arrays

Fixed size array a(10) $20;

Fixed type character or numeric

Imagine: hiearchical data on a tape

Rec. type 1: Person details

Rec. type 2:Allowance details (0 to many)

Need to perform array processing on allowances

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SCL Arrays (2)SCL Arrays (2) Data allow1;

Infile ...Input ...

Allw_type $4.Allw_start ddmmyy8.Allw_end ddmmyy8. ;

array types(10) _temporary_ $4;

array starts(10) _temporary_ ;array ends(10) _temporary_ ;if thendo;allw_no + 1;types{allw_no} = allw_type;

starts{allw_no} = allw_start;ends{allw_no} = allw_end;

end;elsedo;... extra array processing ...

end;

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SCL Arrays (3)SCL Arrays (3)

Static arrays are fixed

SCLsupports dynamic arrays

Special functions define dynamic arrays:Declare char arrayname(*);

Arrayname = makearray(10);rc = redim(arrayname, 20);

Extra array functionsthat only exist in SCL,e.g: asort - for array sorting copyarray comparearray

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SCL Arrays (4)SCL Arrays (4)

EquivalentSCL:declare char types(*);declare num starts(*);declare num ends(*);...types = makearray(1);starts = makearray(1);ends = makearray(1);...fid = fopen(...);do while (fread(fid) = 0);

...if thendo;rc = redim(types, dim(types) + 1);types{dim(types} = allw_type;...

end;

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SCL ListsSCL Lists

SCLLists are really dynamic

elements added (& deleted) without redim

elementscan be differenttypes

elementscan besub-lists

elementscan have names

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SCL Lists (2)SCL Lists (2)

ListN am e (C )F red S m ith

D O B (N )2098

A l l o w a n c e (L)123

A l l o wa n c e (L)125

Type (C)

NS

Start (C)

14566End (C)

14602

Type (C)

D

Start (C)

14710End (C)

14790

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SCL Lists (3)SCL Lists (3)

SCLusing lists:fid = fopen(...);do while (fread(fid) = 0);...if then

personList = makelist();

...if thendo;allwDetail = makelist();rc = insertc(allwDetail, allw_type, -1, 'TYPE');rc = insertn(allwDetail, allw_start, -1, 'START');

rc = insertn(allwDetail, allw_end, -1, 'END');

rc = insertl(personList, allwDetail,-1,"Allowance");...

end;

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SCL Lists (4)SCL Lists (4)

SCLLists havespecial functions

Search, reverse, rotateelements

Listscan besaved asSLISTcatalogentries

Alternative data structureto SAS data sets- for

the rightshaped data.

Notsuitable for large amounts of data - SCL lists

are held in memory.

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Base SAS & SCL DifferencesBase SAS & SCL Differences

SCLLENGTH function returns 0 for a null string (instead of1)

SCLSELECT can'tcope with multiple values e.g.SELECT (ITEM);WHEN ('A', 'B') ... /* Not allowed */

IN operator

array list{3} $10 ('cat','bird','dog');i='dog' in ('cat','bird','dog');

/* i=3 in SCL i=1 in Data Step */j='dog' in list; /* Only in SCL */

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Using SCL withBase SASUsing SCL withBase SAS

PROCDISPLAYto run an SCL program

e.g. proc display c=sasuser.profile.test.scl

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Using Base SAS with SCLUsing Base SAS with SCL

Within SCLcode, BaseSAS isexecuted in a SUBMIT

block

E.G.init:

dataset = sashelp.prdsales;SUBMIT continue;

proc print data=&dataset;run;

ENDSUBMIT;return;

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SummarySummary

So why bother with SCL?

Extra features:

Dynamic arraysSCLListsOther functions

Greater flexibility

Can be faster because already compiled ( Job Security?! )