I find it odd that RPG's Const keyword will allow for conversion
from non-varying to varying, but not vice-versa. But so long as I
know that, I can live with it.
I appreciate knowing how I can not have to create a separate
procedure. I took your suggestion and applied it to a scenario I
hadn't mentioned - where isTollFree could be passed a numeric field.
Instead of using a separate procedure like I was doing with Char and
VarChar, this is what I'm now doing:
Create or Replace Function ccdlib/isTollFree (ANI dec(25,0))
Declare rtnChar Char(1);
Set rtnChar = isTollFree(char(ANI));
I tried with Source, but wasn't sure how to cast the parameter in
CRPence on Sunday, April 22, 2012 5:49 PM wrote:
I am responding again, in a separate message from my prior reply,
to explain separately, an alternative means to resolve the
original scenario; i.e. allowing a literal string as the argument
for the function without having to use the CHAR cast function on
the literal. While not as good IMO as having just one procedure
using varying and just one UDF using VARCHAR to match, as I alluded
in the prior message, but...
This resolution is possible without having to create a new
procedure as well as allowing the original procedure to remain
unchanged. This can be effected with overloading the UDF, just
like with reference to a new procedure, but using an effective CAST
to allow the originally coded procedure to process both SQL UDFs.
For example, by making the new UDF function in the manner that is
hopefully conveyed by the intended effect of the following
pseudo-coding [an unavailable syntax which IMO would be much
clearer than "sourcing" existing functions]:
create function isTollFree( ANI VarChar(20) CAST TO CHAR(20) ) ...
Referring to the original scenario which remains in the quoted
message text below, the given procedure with a prototyped
fixed-length 20-byte character string remains the same, and no
additional procedure is created. The same UDF as shown and
originally created would still be created using the CHAR(20) to
match the expected input for the only argument of the UDF; i.e.
matching declaration between the SQL and the prototyped
fixed-length 20-byte character string. The next step is to create
additionally, an overloaded UDF that will still be processed by
that same external name [i.e. by the same procedure in the service
program], but enabling the literal [which in the SQL docs the term
is "constant"] value to be implicitly typed as VARCHAR by the SQL
and thus enabling the SQL /function resolution/ feature to find a
create function ccdlib/isTollFree /* same routine name */
( ANI varchar(20) ) /* enable character constant as VARCHAR */
returns char(1) /* same return data type */
specific istollfreeVC /* optional naming; e.g. enabling DROP */
source ccdlib/isTollFree(char(20)) /* "source" original UDF */
Having done the above additional CREATE FUNCTION, the request to
perform the SQL isTollFree('800') for which the literal\constant
value '800' is implicitly typed as VARCHAR, the compatible function
named isTollFree with the matching VARCHAR declaration [specific
named function isTollFreeVC] is located using Function Resolution
and Best Fit processing by the SQL run-time [instead of failing
with SQL0204 or SQL0440]. Having /sourced/ the original function
defined as CHAR(20), the SQL properly casts the input value from
VARCHAR(20) of the new UDF to a CHAR(20) value which is then passed
to the same procedure 'CCDLIB/ANIPROCS($ISTOLLFREE)' as noted by
the source function; i.e. the new UDF uses the same procedure used
to implement the source\original UDF.
_CREATE FUNCTION (Sourced)_
"This CREATE FUNCTION (Sourced) statement is used to create a
user-defined function, based on another existing scalar or
aggregate function, at the current server. ..."
On 16 Apr 2012 08:40, Kurt Anderson wrote:
So creating a separate function expecting VarChar that pointed to
a separate procedure that expected a Varying field did the
Thankfully SQL supports overloading, so the user can use the
same function name regardless of the file's field type.
Thanks for your input.
CRPence on Sunday, April 15, 2012 12:35 AM wrote:
On 13-Apr-2012 13:44 , Kurt Anderson wrote:
Here is my Function:
Create or Replace Function ccdlib/isTollFree ( ANI Char(20) )
external name 'CCDLIB/ANIPROCS($ISTOLLFREE)'
parameter style general
The service program procedure's prototype:
// Is the Number Toll-Free?
D $isTollFree PR n
D NPA 20a Const