Instructions

Comments are supported, and may appear anywhere that a space can, with
the exception that comments are not allowed within a multi-character
operator (e.g. ** or ==).  They can occupy any number of lines and may
be nested. 
/* This is a comment.  It is started by /* and ended by */.  */

The star and slash characters of the comment delimiters must not be
separated by whitespace.

Each command must usually appear all on one line. The exception to this
rule is when a line ends with a comma. In this instance, the comma is
deleted and the next line appended with a space. Multiple lines may be
appended in this way. Thus
   say,          /* spaces and/or comments may follow the comma */
   "this is",
   "a test"
will actually be interpreted as
   say "this is" "a test"
and will result in
   this is a test

Note that quotation marks must always be closed before the end of a line.
For example, the following will cause an error:
   say "this is,
   a test"

Instructions may be separated by semicolons or by the ends of lines.

The following REXX commands are currently implemented. They are displayed
in upper case, but may be typed in mixed case.

Square brackets indicate optional parts of constructions.