Validation Pattern MUMPS

I am working to create a program in M that reads an input of names in a certain format. Once the user places a null value it prints out all of the values. Where I am getting stuck is reading into a global variable. I look forward to any input I can receive.

          n prompt,val,done
          s prompt="Enter a name (LAST,FIRST MI): "
          s val="" f in=1:1 s val=$O(^ZNAME(val)) q:val=""
          f  w !,prompt r val q:val=""  d   q:done 
          . i val'?1.A1",".1" "1.A.1(1" "1A) w !,"Invalid name" q
          . s val=$GET(^ZNAME)
          . s done=1
          i val="" q  
          w !,"You entered: ",val
         . s done=1
         q

I don't completely understand what you want to do but this is what I built:

• read names till you give an empty name
• if the name follows a pattern add him to ^ZNAME
• at the end print all names in ^ZNAME

Here you go:

readlist
    N prompt,val
    S prompt="Enter a name (LAST,FIRST MI): "
    F  W !,prompt R val Q:val=""  D
    .   I val'?1.A1",".1" "1.A.1(1" "1A) W !,"Invalid name"
    .   E  S ^ZNAME(val)=""
    F  S val=$O(^ZNAME(val)) Q:val=""  D
    .   W !,"You entered: ",val
    Q

Example (using GTM):

GTM>D readlist^ZZTEST

Enter a name (LAST,FIRST MI): first,last
Enter a name (LAST,FIRST MI): name,surname
Enter a name (LAST,FIRST MI):
You entered: first,last
You entered: name,surname
GTM>zwr ^ZNAME
^ZNAME("first,last")=""
^ZNAME("name,surname")=""