/*<pre><b>
/ Program   : optlength.sas
/ Version   : 1.0
/ Author    : Roland Rashleigh-Berry
/ Date      : 04-May-2011
/ Purpose   : To create a length statement for character variables that take up
/             less length than that allotted to the variable.
/ SubMacros : %nvarsc
/ Notes     : The length statement will get written out to a global macro
/             variable. Only those character variables whose longest length is
/             less than the allotted length will be output. 
/ Usage     : optlength(dset)
/             data dset;
/               &_optlength_;
/               set dset;
/             run;
/ 
/===============================================================================
/ PARAMETERS:
/-------name------- -------------------------description------------------------
/ dsin              (pos) Input dataset
/ globvar=_optlength_ Name of global macro variable.
/===============================================================================
/ AMENDMENT HISTORY:
/ init --date-- mod-id ----------------------description------------------------
/ rrb  29Mar07         Put out "macro called" message plus header tidy
/ rrb  04May11         Code tidy
/===============================================================================
/ This is public domain software. No guarantee as to suitability or accuracy is
/ given or implied. User uses this code entirely at their own risk.
/=============================================================================*/

%put MACRO CALLED: optlength v1.0;

%macro optlength(dsin,globvar=_optlength_);

  %local nvarsc;
  %global &globvar;
  %let &globvar=;

  %let nvarsc=%nvarsc(%scan(&dsin,1,%str(%()));
  %if not &nvarsc %then %goto exit;

  data _null_;
    set &dsin end=last;
    array _char {*} _character_;
    length _str $ 32767;
    array _length {&nvarsc} 8 _temporary_ (&nvarsc*1);
    do _i=1 to dim(_char);
      if length(_char(_i))>_length(_i) then _length(_i)=length(_char(_i));
    end;
    if last then do;
      _str='length';
      do _i=1 to dim(_char);
        if _length(_i)<vlength(_char(_i)) then _str=trim(_str)||' '||trim(vname(_char(_i)))||
        ' $ '||compress(put(_length(_i),5.));
      end;
      if _str NE 'length' then call symput("&globvar",trim(_str));
    end;
  run;

  %exit:

%mend optlength;