Editing Object REXX (section)

=== Procedure and function ===
ooRexx provides a new way to define procedures and functions that are not specific to a particular class by using the <code>::ROUTINE</code> [[Object REXX#Instructions|directive]]; unlike the older <code>PROCEDURE</code>, code defined with <code>::ROUTINE</code> has an implicit <code>RETURN</code> at the end. The <code>CALL</code> instruction can be used to invoke a routine as a procedure. In addition, routines that return values via the <code>RETURN</code> keyword instructions can be called using function calls by specifying the name of the routine followed by parentheses. The content within the brackets is passed as an argument to a routine. While the <code>PARSE ARG</code> instruction can be used to parse received string arguments and assign them to variables, the newer <code>USE ARG</code> must be used for objects of other types. In addition, the <code>STRICT</code> option can be used to limit the number of arguments that must match the number of specified names.<ref name=":2" /><syntaxhighlight lang="oorexx" style="background-color: #ffffff; !important" line="1">call DoSomething                        /* "CALL" keyword instruction        */
table = .stem~new                       /* Stem object for indsum            */
table[1] = 2; table[2] = 4
say indsum{table,1.2)                   /* function call requiring use arg   */
say dirsum(2,4)                         /* either parse arge or use arg okay */

::Routine DoSomething                   /* "ROUTINE" directive (procedure)   */
  say "I did something!"                /* output: I did something!          */
                                        /* Implicit return because next      */
                                        /* statement is a directive.         */

::Routine dirsum                        /* "ROUTINE" directive (function)    */
  parse arg first, second               /* Valid because both are strings.   */
  return first+second

::Routine indsum                        /* "ROUTINE" directive (function)    */
  use strict arg table, first, second   /* can't use parse arg with stem arg */
  Sum = table{first} + table[second]    /* do calculation                    */
  return Sum                            /* "RETURN" result                   */</syntaxhighlight>