Re: "Validate" file name via regex pattern in CL?

On Tue, Mar 6, 2018 at 12:47 PM, <dlclark@xxxxxxxxxxxxxxxx> wrote:

"MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx> wrote on 03/06/2018
12:13:38 PM:
For fixed-length data with a fixed format I would not bother with
REGEX. I would also avoid %SST, though, by using the new ability to
redefine CL variables -- which basically means creating a data structure
format with subfields for the different parts of your string. For
example:

DCL VAR(&FILENAME) TYPE(*CHAR) LEN(40)
DCL VAR(&F_PREFIX) TYPE(*CHAR) LEN(19) STG(*DEFINED) DEFVAR(&FILENAME 1)
DCL VAR(&F_MO) TYPE(*CHAR) LEN( 2) STG(*DEFINED) DEFVAR(&FILENAME 20)
DCL VAR(&F_MO_DOT) TYPE(*CHAR) LEN( 1) STG(*DEFINED) DEFVAR(&FILENAME 22)
DCL VAR(&F_DD) TYPE(*CHAR) LEN( 2) STG(*DEFINED) DEFVAR(&FILENAME 23)
DCL VAR(&F_DD_DOT) TYPE(*CHAR) LEN( 1) STG(*DEFINED) DEFVAR(&FILENAME 25)
DCL VAR(&F_YY) TYPE(*CHAR) LEN( 2) STG(*DEFINED) DEFVAR(&FILENAME 26)
DCL VAR(&F_YY_ULN) TYPE(*CHAR) LEN( 1) STG(*DEFINED) DEFVAR(&FILENAME 28)
DCL VAR(&F_HH) TYPE(*CHAR) LEN( 2) STG(*DEFINED) DEFVAR(&FILENAME 29)
DCL VAR(&F_MM) TYPE(*CHAR) LEN( 2) STG(*DEFINED) DEFVAR(&FILENAME 31)
DCL VAR(&F_SUFFIX) TYPE(*CHAR) LEN( 4) STG(*DEFINED) DEFVAR(&FILENAME 33)
DCL VAR(&F_EXTRA) TYPE(*CHAR) LEN( 4) STG(*DEFINED) DEFVAR(&FILENAME 37)

Wow. Wall o' code.

I appreciate that CL has grown in capability. But it's... not the most
beautiful language to code in.

I actually *would* use %SST, because that's less verbose than what
you've shown here! Especially since some of the "subfields" only exist
to test against a constant. Besides reducing verbosity and line count,
I also like to reduce the number of variables.

Of course, my preference would still be a simple RPG helper program.
With its date/time BIFs, you can do more precise validation. (Or did
CL grow date/time BIFs as well?) In fact, it's better validation than
regex alone (typically, those just check whether certain characters
are digits, not whether they form valid dates).

John Y.