/* mkvarlist.sas Daniel Brockman Make list of var names in a data set. */ 
/* --------------------------------------------------------- */
%macro mkvarlist(inp) ;

/* 
* %mkvarlist returns, in global variable greturn,
* a list of the names of the variables in input data set &inp .
* Example: 
* %global greturn ;
* %mkvarlist(mylib.mydataset) ;
* %let vlist = &greturn ;
*/

/* make names of temporary data sets */
/* This ijk stuff extracts the 1st 4 chars of the libname */
%let k = %scan(&inp,1) ;
%let i = %length(&k) ;
%let j = %eval(&i-3) ;
%if ( &i < 1 ) %then %let k = ;
%else %if ( &i > 4 ) %then %let k = %substr(&k,&j,4) ;
%else %let k = %substr(&k,1,&i) ;
/* This ijk stuff extracts the last 4 chars of the dataset name */
%let L = %scan(&inp,2) ;
%let i = %length(&L) ;
%let j = %eval(&i-3) ;
%if ( &i < 1 ) %then %let L = ;
%else %if ( &i > 4 ) %then %let L = %substr(&L,&j,4) ;
%else %let L = %substr(&L,1,&i) ;

%let c3po = &k.&L._c3p ;   /* temporary data set for proc contents output */

;

/* put the names of the input set variables in data set &c3po ; */
proc contents data=&inp 
               noprint 
               varnum 
              out=&c3po ;
run;

/* extract names of variables into macro var mkvlist */
data _NULL_ ;
  set &c3po;
  length ob2kinob $ 8192;   /* I hope this is long enough */
  retain ob2kinob;
  if (_N_=1) then ob2kinob=trim(name);
    else ob2kinob= trim(ob2kinob) || ' ' || trim(name) ;
  call symput('mkvlist',trim(ob2kinob));
run;

/* assume the value of the list of variables */
%let greturn = &mkvlist. ;;  /* this works */
/* * &mkvlist. ;;   this doesn' t work */
%mend mkvarlist;

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;