System Functions
ARG( ) Parse string arguments
  The following ARG function options are +PxPlus Exclusive
Format 1. Return argument from string:

ARG( string$, argno [, delim$ ] [,ERR=stmtref])

2. Replace argument in string :

ARG ( EDIT string$, argno, newval$ [, delim$ ] [,ERR=stmtref])

Where:

  string$ String containing a series of arguments/values each separated by a single character.
   
  argno The number of the argument in the string to return or relpace. (one based)
   
  delim$ The character that separates each of the values string$. If omitted the system default field separator is used.
   
  newval$ The new value to insert into string$.
   
  stmtref Program line number or statement label to which to transfer control.
   
Format 1 This form of the ARG function extracts a specific field from a delimited string. If no delimiter is specified, the system uses the default SEP character (normally $8A$).
   
Format 2 This form of the ARG generates and returns a new string replacing the field specified with that supplied in <newvalue>. If the field specified did not exist, additional delimiters will be added in the string to make up for the missing fields. If no delimiter is specified, the system uses the default SEP character.
   
Example Given X$ = "a,b,c,d,e,"
   
ARG(X$, 1, ",") Returns "a"
ARG(EDIT X$, 2, "Cat", ",") Returns "a,Cat,c,d,e,"
ARG(EDIT X$, 7, "Dog", ",") Returns "a,b,c,d,e,,Dog,"