On Friday, 96/01/05, Ruud Senden wrote to David Noon about "REXX
syntax-checker" as follows:

RS>  DN> This is not correct. The code -- other than inside INTERPRET
RS>  DN> statements -- is syntax checked by the tokenizer when the REXX exec
RS>  DN> is loaded.
RS> 
RS> Well, I have tried some things, but it doesn't recognize the
RS> errors I  introduced. For example, if a long REXX-command is divided
RS>  over multiple lines, there should be a , at the end of each  line as
RS> a continuation character. But when I leave the ,  away, the
RS> REXX-program still runs, until it comes to that  piece of code,
RS> where REXX generates a syntax error.

Hi Ruud,

As I said in my other message, what you are seeing here is REXX
ignoring something it cannot fathom and passing it to CMD.EXE -- or
whatever subcommand handler is handling the default ADDRESS. There
might be enough remnants of your source that are almost valid REXX and
these would give you a syntax error.

Syntax checking will only be effective if your code is close to valid.
Anything that looks like complete gobbledy-gook to REXX will be
retained as is and passed to the ADDRESS handler that is active at
exxecution time.

However, a long REXX statement should burp at load time with a comma
missing. You wrote "REXX-command", so I am not sure whether you mean an
OS/2 command that REXX is to pass to CMD.EXE or a native REXX
statement. If it is a command, rather than a statement, syntax errors
will not be detected until run time, because it isn't REXX syntax.

I try to avoid issuing OS/2 commands when I am writing a REXX exec. I
find that using native REXX statements gives me much tighter checking
of my program's syntax, simply because it is all REXX syntax. Of
course, sometimes issuing a command is unavoidable, but then I always
use

  ADDRESS 'CMD' ''

so that it is brought back into REXX syntax for load-time checking.
This approach also allows me to issue OS/2 commands when CMD.EXE is not
the default subcommand handler, such as in a PM program prepared by
VisPro REXX.

Regards

Dave

--- Maximus/2 3.01