feat: new mfv_existsashdat() macro for checking whether a dataset exi…

…sts in persistent storage

all.sas

@@ -22170,6 +22170,66 @@ run;
   %end;
 
 %mend mfv_existfolder;/**
+  @file mfv_existsashdat.sas
+  @brief Checks whether a CAS sashdat dataset exists in persistent storage.
+  @details Can be used in open code, eg as follows:
+
+      %if %mfv_existsashdat(libds=casuser.sometable) %then %put  yes it does!;
+
+  The function uses `dosubl()` to run the `table.fileinfo` action, for the
+  specified library, filtering for `*.sashdat` tables.  The results are stored
+  in a WORK table (&outprefix._&lib). If that table already exists, it is
+  queried instead, to avoid the dosubl() performance hit.
+
+  To force a rescan, just use a new `&outprefix` value, or delete the table(s)
+  before running the function.
+
+  @param libds library.dataset
+  @param outprefix= (work.mfv_existsashdat) Used to store the current HDATA
+    tables to improve subsequent query performance.  This reference is a prefix
+    and is converted to `&prefix._{libref}`
+
+  @return output returns 1 or 0
+
+  @version 0.2
+  @author Mathieu Blauw
+**/
+
+%macro mfv_existsashdat(libds,outprefix=work.mfv_existsashdat
+);
+%local rc dsid name lib ds;
+%let lib=%upcase(%scan(&libds,1,'.'));
+%let ds=%upcase(%scan(&libds,-1,'.'));
+
+/* if table does not exist, create it */
+%if %sysfunc(exist(&outprefix._&lib)) ne 1 %then %do;
+  %let rc=%sysfunc(dosubl(%nrstr(
+    /* Read in table list (once per &lib per session) */
+    proc cas;
+      table.fileinfo result=source_list /caslib="&lib";
+      val=findtable(source_list);
+      saveresult val dataout=&outprefix._&lib;
+    quit;
+    /* Only keep name, without file extension */
+    data &outprefix._&lib;
+      set &outprefix._&lib(where=(Name like '%.sashdat') keep=Name);
+      Name=upcase(scan(Name,1,'.'));
+    run;
+  )));
+%end;
+
+/* Scan table for hdat existence */
+%let dsid=%sysfunc(open(&outprefix._&lib(where=(name="&ds"))));
+%syscall set(dsid);
+%let rc = %sysfunc(fetch(&dsid));
+%let rc = %sysfunc(close(&dsid));
+
+/* Return result */
+%if "%trim(&name)"="%trim(&ds)" %then 1;
+%else 0;
+
+%mend mfv_existsashdat;
+/**
   @file
   @brief Creates a file in SAS Drive
   @details Creates a file in SAS Drive and adds the appropriate content type.

viya/mfv_existsashdat.sas

@@ -0,0 +1,60 @@
+/**
+  @file mfv_existsashdat.sas
+  @brief Checks whether a CAS sashdat dataset exists in persistent storage.
+  @details Can be used in open code, eg as follows:
+
+      %if %mfv_existsashdat(libds=casuser.sometable) %then %put  yes it does!;
+
+  The function uses `dosubl()` to run the `table.fileinfo` action, for the
+  specified library, filtering for `*.sashdat` tables.  The results are stored
+  in a WORK table (&outprefix._&lib). If that table already exists, it is
+  queried instead, to avoid the dosubl() performance hit.
+
+  To force a rescan, just use a new `&outprefix` value, or delete the table(s)
+  before running the function.
+
+  @param libds library.dataset
+  @param outprefix= (work.mfv_existsashdat) Used to store the current HDATA
+    tables to improve subsequent query performance.  This reference is a prefix
+    and is converted to `&prefix._{libref}`
+
+  @return output returns 1 or 0
+
+  @version 0.2
+  @author Mathieu Blauw
+**/
+
+%macro mfv_existsashdat(libds,outprefix=work.mfv_existsashdat
+);
+%local rc dsid name lib ds;
+%let lib=%upcase(%scan(&libds,1,'.'));
+%let ds=%upcase(%scan(&libds,-1,'.'));
+
+/* if table does not exist, create it */
+%if %sysfunc(exist(&outprefix._&lib)) ne 1 %then %do;
+  %let rc=%sysfunc(dosubl(%nrstr(
+    /* Read in table list (once per &lib per session) */
+    proc cas;
+      table.fileinfo result=source_list /caslib="&lib";
+      val=findtable(source_list);
+      saveresult val dataout=&outprefix._&lib;
+    quit;
+    /* Only keep name, without file extension */
+    data &outprefix._&lib;
+      set &outprefix._&lib(where=(Name like '%.sashdat') keep=Name);
+      Name=upcase(scan(Name,1,'.'));
+    run;
+  )));
+%end;
+
+/* Scan table for hdat existence */
+%let dsid=%sysfunc(open(&outprefix._&lib(where=(name="&ds"))));
+%syscall set(dsid);
+%let rc = %sysfunc(fetch(&dsid));
+%let rc = %sysfunc(close(&dsid));
+
+/* Return result */
+%if "%trim(&name)"="%trim(&ds)" %then 1;
+%else 0;
+
+%mend mfv_existsashdat;