LUA - it is safe to drive SAS

PROC LUA can create safe environment to drive SAS because you don't worry about changing any existing library, fileref, macros and global options outside LUA session. Furthermore, you can also setup new library, fileref, macros and global options in LUA session. It will maintain all of them inside LUA session until it terminates or restarts.

Below are the sample code to demonstrate the concepts:

filename test temp;
libname test "c:\";
%macro test;
    %put outside;
%mend;

proc lua restart;
submit;
sas.submit [[
/* It will fail to delete existing fileref or library */
filename test clear;
libname test clear;
]]
endsubmit;
run;

proc lua restart;
submit;
sas.submit [[
filename test temp;
libname test "c:\temp";
options obs=0;
%macro test;
    %put inside;
%mend;

filename test list;
libname test list;
proc options option=obs; run;
%test
]]
endsubmit;
run;

filename test list;
libname test list;
proc options option=obs; run;
%test

How to call LUA file?

As we know, LUA is great fit to SAS. Here are some tips on how to integrate LUA file into SAS.

For example, the LUA file is at c:\lua\test.lua

/* #1. using INFILE option of PROC LUA */
FILENAME LUAPATH "c:\lua";
PROC LUA INFILE="test"; RUN;

/* #2. leverage current folder */
X "CD c:\lua";
PROC LUA;
SUBMIT;
dofile("test.lua")
ENDSUBMIT;
RUN;

/* #3. using absolute path */
PROC LUA;
SUBMIT;
dofile(c:\\lua\\test.lua) -- escape backslash character
dofile [[c:\lua\test.lua]] -- or using [[ and ]]
ENDSUBMIT;
RUN;

/* #4. %INCLUDE statement supports both SAS and LUA starting from 9.4 */
%INCLUDE "c:\lua\test.lua";

/* $5. passed by SUBMIT option */
%let luaname=c:\lua\test.lua;

PROC LUA;
SUBMIT "name=[[&luaname]]";
    print(name)
    dofile(name)
ENDSUBMIT;
RUN;

New way to keep data structure in DATA step

In most time, you don't want to add any new variable in DATA step. Normally we create one list of all original variables before DATA step. Actually we can have better way to address this. Please see codes at below:

DATA TEST (DROP=START -- END);
    IF 0 THEN SET SASHELP.CLASS;
    IF 0 THEN START = 0;

    SET SASHELP.CLASS;

    A=1;B=1; * Test Variables;

    IF 0 THEN END = 0;
RUN;