IF THEN ELSE MACRO IN SAS

Question

I have to create EVENT1-EVENT20 but am doing mannualy adding one by one, Its painfull to add all the events and code looks ugly, Is there any way to do simply, like adding macro?

DATA Z3_ALL91;
SET Z3_ALL8;

EVENT1=INPUT('.',$CHAR10.);
EVENT2=INPUT('.',$CHAR10.);
EVENT3=INPUT('.',$CHAR10.);
EVENT4=INPUT('.',$CHAR10.);

IF RE1='HO'  THEN EVENT1=ERP1;
IF RE1='RE'  THEN EVENT1='REP';
IF RE1='HSS' THEN EVENT1=ERP1;

IF RE2='HO' THEN EVENT2=ERP2; ELSE
IF RE2='RE' THEN EVENT2='REP';ELSE
IF (RE2='HSS' AND ROH1^="") THEN EVENT2=CATX("_",ERP2,ROH1);ELSE EVENT2=ERP2;

IF RE3='HO' THEN EVENT3=ERP3; ELSE
IF RE3='RE' THEN EVENT3='REP';ELSE
IF (RE3='HSS' AND ROH2>ROH1) THEN EVENT3=CATX("_",ERP3,ROH2);ELSE
IF (RE3='HSS' AND ROH1^=".") THEN EVENT3=CATX("_",ERP3,ROH1);ELSE EVENT3=ERP3;

IF RE4='HO' THEN EVENT4=ERP4; ELSE
IF RE4='RE' THEN EVENT4='REP';ELSE
IF (RE4='HSS' AND ROH3>ROH2) THEN EVENT4=CATX("_",ERP4,ROH3);ELSE
IF (RE4='HSS' AND ROH2>ROH1) THEN EVENT4=CATX("_",ERP4,ROH2);ELSE 
IF (RE4='HSS' AND ROH1^=".") THEN EVENT4=CATX("_",ERP4,ROH1);ELSE EVENT4=ERP4;

RUN;

Answer 1

Here's my attempt at it...

%MACRO EVENTS(N) ;
  %IF &N = 1 %THEN %DO ;
    if RE&N = 'HO' then EVENT&N = ERP&N ;
    else
    if RE&N = 'RE' then EVENT&N = 'REP' ;
    else
    if RE&N = 'HSS' then EVENT&N = ERP&N ;
  %END ;
  %ELSE %DO ;
    if RE&N = 'HO' then EVENT&N = ERP&N ;
    else
    if RE&N = 'RE' then EVENT&N = 'REP' ;
    else
    %DO L1 = %EVAL(&N - 1) %TO 1 %BY -1 ;
      %LET L2 = %EVAL(&L1 - 1) ;
      %IF &L1 = 1 %THEN %DO ;
        if (RE&N = 'HSS' and ROH&L1 ^= ".") then EVENT&N = catx('_',ERP&N,ROP&L1) ;
      %END ;
      %ELSE %DO ;
        if (RE&N = 'HSS' and ROH&L1 > ROH&L2) then EVENT&N = catx('_',ERP&N,ROP&L1) ;
      %END ;
      else
    %END ;
    EVENT&N = ERP&N ;
  %END ;
%MEND ;

options nosymbolgen ;

data z3_all91 ;
  set z3_all8 ;

  EVENT1 = input('.',$CHAR10.);
  EVENT2 = input('.',$CHAR10.);
  EVENT3 = input('.',$CHAR10.);
  EVENT4 = input('.',$CHAR10.);

  %EVENTS(1) ;
  %EVENTS(2) ;
  %EVENTS(3) ;
  %EVENTS(4) ;
run ;

And the generated code in the log :

3940  data z3_all91 ;
3941    set z3_all8 ;
3942    EVENT1 = input('.',$CHAR10.);
3943    EVENT2 = input('.',$CHAR10.);
3944    EVENT3 = input('.',$CHAR10.);
3945    EVENT4 = input('.',$CHAR10.);
3946    %EVENTS(1) ;
MPRINT(EVENTS):   if RE1 = 'HO' then EVENT1 = ERP1 ;
MPRINT(EVENTS):   else if RE1 = 'RE' then EVENT1 = 'REP' ;
MPRINT(EVENTS):   else if RE1 = 'HSS' then EVENT1 = ERP1 ;
3947    %EVENTS(2) ;
MPRINT(EVENTS):   if RE2 = 'HO' then EVENT2 = ERP2 ;
MPRINT(EVENTS):   else if RE2 = 'RE' then EVENT2 = 'REP' ;
MPRINT(EVENTS):   else if (RE2 = 'HSS' and ROH1 ^= ".") then EVENT2 = catx('_',ERP2,ROP1) ;
MPRINT(EVENTS):   else EVENT2 = ERP2 ;
3948    %EVENTS(3) ;
MPRINT(EVENTS):   if RE3 = 'HO' then EVENT3 = ERP3 ;
MPRINT(EVENTS):   else if RE3 = 'RE' then EVENT3 = 'REP' ;
MPRINT(EVENTS):   else if (RE3 = 'HSS' and ROH2 > ROH1) then EVENT3 = catx('_',ERP3,ROP2) ;
MPRINT(EVENTS):   else if (RE3 = 'HSS' and ROH1 ^= ".") then EVENT3 = catx('_',ERP3,ROP1) ;
MPRINT(EVENTS):   else EVENT3 = ERP3 ;
3949    %EVENTS(4) ;
MPRINT(EVENTS):   if RE4 = 'HO' then EVENT4 = ERP4 ;
MPRINT(EVENTS):   else if RE4 = 'RE' then EVENT4 = 'REP' ;
MPRINT(EVENTS):   else if (RE4 = 'HSS' and ROH3 > ROH2) then EVENT4 = catx('_',ERP4,ROP3) ;
MPRINT(EVENTS):   else if (RE4 = 'HSS' and ROH2 > ROH1) then EVENT4 = catx('_',ERP4,ROP2) ;
MPRINT(EVENTS):   else if (RE4 = 'HSS' and ROH1 ^= ".") then EVENT4 = catx('_',ERP4,ROP1) ;
MPRINT(EVENTS):   else EVENT4 = ERP4 ;
3950  run ;