feat: adding mp_gsubfile.sas - a SAS macro that uses Lua to perform a full text find and replace of an entire file. Not restricted by number of characters (only memory). IIncludes a test.

base/mp_gsubfile.sas

@@ -0,0 +1,53 @@
+/**
+  @file
+  @brief Performs a text substitution on a file
+  @details Makes use of the GSUB function in LUA to perform a text substitution
+  in a file - either in-place, or writing to a new location.  The benefit of
+  using LUA is that the entire file can be loaded into a single variable,
+  thereby side stepping the 32767 character limit in a data step.
+
+  Usage:
+
+      %let file=%sysfunc(pathname(work))/file.txt;
+      %let str=replace/me;
+      %let rep=with/this;
+      data _null_;
+        file "&file";
+        put "&str";
+      run;
+      %mp_gsubfile(file=&file, pattern=str, replacement=rep)
+      data _null_;
+        infile "&file";
+        input;
+        list;
+      run;
+
+  @param file= (0) The file to perform the substitution on
+  @param patternvar= A macro variable containing the Lua
+  [pattern](https://www.lua.org/pil/20.2.html) to search for.  Due to the use
+  of special (magic) characters in Lua patterns, it is safer to pass the NAME
+  of the macro variable containing the string, rather than the value itself.
+  @param replacevar= The name of the macro variable containing the replacement
+  _string_.
+  @param outfile= (0) The file to write the output to. If zero, then the file
+  is overwritten in-place.
+
+  <h4> SAS Macros </h4>
+  @li ml_gsubfile.sas
+
+  <h4> Related Macros </h4>
+  @li mp_gsubfile.test.sas
+
+  @version 9.4
+  @author Allan Bowe
+**/
+
+%macro mp_gsubfile(file=0,
+  patternvar=,
+  replacevar=,
+  outfile=0
+)/*/STORE SOURCE*/;
+
+  %ml_gsubfile()
+
+%mend mp_gsubfile;