It is advisable to start REXX programs with a comment. A REXX program is built from a
series of clauses.
REXX programs are recommended to start with a comment. REXX/CICS does not require that REXX
programs start with a comment. However, for portability reasons, it is advisable to start each REXX
program with a comment that begins on the first line and includes the word REXX, as
shown in the following example. Figure 1. Example of using the REXX program identifier
/* REXX program */
...
...
...
EXIT
A REXX program is built from a series of clauses that are composed of:
A semicolon (;) delimiter that can be implied by line-end, certain keywords, or the colon
(:).
Conceptually, each clause is scanned from left to right before processing, and the tokens that
compose the clause are identified. At this stage, instruction keywords are recognized, comments are
removed, and multiple blanks (except in literal strings) are converted to single blanks. Blanks
adjacent to operator characters and special characters are also removed (see Tokens) .
Implementation maximum: The length of a clause cannot exceed 16K.