Jeff:

In my opinion, the programmer should code according to the generally 
accepted methods of programming using equations. 

The syntax for: !p1*(!p1-1) should be (!p1)*((!p1)-1).

This method would standardize both types of uses.

Just my 2 cents worth.

Olav.


Vance, Jeff H (Cupertino) wrote:

>Hi all,
>
>I am seeking your opinions on an aspect of a recent SIB CI enhancement
>called "User Functions". 
>
>Background:
>-----------
>User functions are basically UDCs or scripts which return a value via
>their name, when invoked. For example, a simple user function named ADD
>returns the sum of two numbers:
>  PARM n1,n2
>  return !n1+!n2
>
>ADD could be invoked as:
>  if add(3,myvar) < 4 then ...
>
>See Jazz at
>http://jazz.external.hp.com/papers/Communicator/7.5/UserFunctions.txt
>for more info on User Functions.
>
>
>Parameters:
>-----------
>In fixing a defect in our user function code, we realized that we are
>making an assumption about how to treat user function parameters.
>Consider these examples:
>
>Filename 1 = SCRIPT.PUB.SYS
>---------------------------
>PARM p1
>echo p1=!p1
>setvar result !p1*(!p1-1)
>showvar result
>
>Filename 2 = FUNC.PUB.SYS 
>-------------------------
>PARM p1
>echo p1=!p1
>return !p1*(!p1-1)
>
>
>Execute the script:
>===================
>:script 4
>p1=4
>RESULT = 12
>
>:script 5-1
>p1=5-1
>RESULT = 2
>
>:script (5-1)
>p1=(5-1)
>RESULT = 12
>
>>From above you can see that we treat all parameter values for UDCs and
>scripts as unevaluated string literals. The middle example appears not
>to work because the expression becomes: 
>   setvar result 5-1*(5-1-1)
>               = 5-1*(3)
>               = 5-3 = 2
>
>
>Execute the user function:
>==========================
>:calc func(4)
>p1=4
>12, $C, %14
>
>:calc func(5-1)
>p1=4
>12, $C, %14
>
>:calc func((5-1))
>p1=4
>12, $C, %14
>
>The middle example here appears to work as one would expect, but is
>inconsistent with how the very similar UDC/script behaves. Note that the
>user function parameters are evaluated prior to being stored.
>(This parameter evaluation has a defect regarding certain string values
>and that's why we are looking at the code.)
>
>We need to decide to either treat user function parameters like the
>other predefined function parameters, or like UDC/script parameters.
>Parameters for almost* all of our predefined functions, e.g.. STR,
>FINFO, etc.) are evaluated before being stored as a parm value.
>Parameters for scripts/UCDs are not evaluated and are simply stored as
>literal string values.
>
>I am very interested in your opinions so we can complete this fix.
>
>thanks,
> Jeff Vance, vCSY
>
>
>* WORD, SETVAR, and WORDCNT have a parameter (the name of a variable)
>which is purposely not evaluated.
>
>* To join/leave the list, search archives, change list settings, *
>* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
>
>
>  
>

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