Hi,
Actually, it is possible. I just got it to work earlier today. The code is
below:
<cfset orderString = iif(isDefined("attributes.order"), "'&order=' &
attributes.order", DE(""))>
Try it - it works.
-Brent
-----Original Message-----
From: Dave Feltenberger [mailto:[EMAIL PROTECTED]]
Sent: Thursday, August 30, 2001 6:08 PM
To: CF-Talk
Subject: RE: IIF and DE
I'd suggest writing your code in a different way - what you're trying to do
(i.e. the way you're doing it) isn't possible.
> -----Original Message-----
> From: Brent Goldman [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 30, 2001 6:41 PM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
> Hi,
>
> Yes, that WILL work, but the second statement in the IIF statement is not
> just a variable, but a string that uses the variable WITHIN. That's the
> problem.
>
> -Brent
>
> -----Original Message-----
> From: Dave Feltenberger [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 30, 2001 8:26 AM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
> Oops. Sorry...
>
> It's this:
>
> <cfset temp1 = "stuff">
>
> <cfoutput>
> #evaluate(IIF(isDefined ("temp1"), DE("temp1"), DE("temp2")))#
> </cfoutput>
>
> The evaluate goes around the IIF instead of around the variable names (I
> didn't think it through well enough before I sent out the message).
>
> Now that's assuming that the other variables *is* defined, of course. The
> IIF still does delayed evaluation correctly though, it's just that many
> ColdFusion programmers have a skewed view of what delayed
> evaluation is and
> how it should work.
>
>
> -----Original Message-----
> From: Tyson Vanek [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 30, 2001 11:06 AM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
> Dave,
>
> Maybe it's just me (it's still early), but I don't understand how your
> example with evaluate() can be considered a workaround for a
> parameter that
> doesn't exist. Using the example you specified still results in the same
> error. Here was Brent's original code (the source of this whole thread):
>
> <cfset orderString =
> iif(isDefined("attributes.order"),DE("&order=#attributes.order
> #"), "")>
> <cflocation url="index.cfm?fuseaction=tools#orderString#>
>
> If I'm understanding your workaround example correctly, here's what you're
> proposing instead:
>
> <cfset orderString =
> iif(isDefined("attributes.order"),DE("#evaluate('&order=#attri
> butes.orde
> r#')#"), "")>
> <cflocation url="index.cfm?fuseaction=tools#orderString#">
>
> Both of these code example produce the exact same result - "Error
> resolving
> parameter attributes.order"
>
> Am I missing something? :)
>
> Regards,
> Tyson
>
> -----Original Message-----
> From: Dave Feltenberger [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 30, 2001 9:41 AM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
>
> ColdFusion doesn't "validate" the entire statement block per se, it's just
> that the variables you pass in are parameters to a function and have to
> exist in order to pass in. Hence the workaround I sent before of using
> evaluate().
>
> Other languages that "short circuit" in if/else if/else blocks
> still have to
> have variables defined in order to pass into functions - there's no magic
> there - it just skips the rest of the block once it matches a condition
> specified. The compiler will complain if the variables aren't
> defined ahead
> of time in languages like C, C++, Java, etc., and since you don't have the
> option of compiling ColdFusion (as far as I know, anyway) to rid
> yourself of
> errors like this, you hit the problem at run-time. IIF does in
> fact "short
> circuit" like it's supposed to.
>
>
> -----Original Message-----
> From: Tyson Vanek [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 30, 2001 10:31 AM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
> Not exactly. IIF() creates an IF/ELSE scenario which,
> technically speaking,
> could be considered two statements even though only one of them
> actually has
> a condition defined.
>
> Fact of the matter is, this comes down to what's called "short circuit"
> logic. In most languages in any if/else pair, once a match with
> one of the
> if clauses is established, the rest of the if/else statement is simply
> ignored - commonly referred to as "short circuiting". You'll find that
> ColdFusion works this way with CFIF, CFELSEIF and CFELSE. However, in the
> case of IIF(), ColdFusion doesn't short circuit which means that
> it tries to
> validate the entire statement block, even though only part of it actually
> needs to execute.
>
>
>
> ---[ begin example 1 ]---
> <cfset strFoo = "foo">
> <cfif isDefined("strFoo") and len(trim(strFoo))>
> <cfoutput>strFoo = #strFoo#</cfoutput>
> <cfelse>
> <cfoutput>strFoo2 = #strFoo2#</cfoutput>
> </cfif>
> ---[ end example 1 ]---
>
> ---[ begin example 2 ]---
> <cfset strFoo = "foo">
> <cfoutput>
> #iif(isDefined("strFoo") and
> len(trim(strFoo)),de(strFoo),de(strFoo2))#
> </cfoutput>
> ---[ end example 2 ]---
>
> Hope that makes sense and/or helps. :)
>
> -Tyson
>
> -----Original Message-----
> From: Brent Goldman [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 29, 2001 8:05 PM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
> Hi,
>
> Good idea, but I think you missed the problem. There is not two different
> expressions to evaluate to be TRUE or FALSE as in your example -- just the
> isDefined function. CF shouldn't be executing the "... blah blah
> blah ...",
> but it does, and that is the problem.
>
> -Brent
>
> -----Original Message-----
> From: Tyson Vanek [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 29, 2001 5:57 PM
> To: CF-Talk
> Subject: RE: IIF and DE
>
>
> This goes back to the way the old <CFIF> used to behave. In the past (I
> think up until CF ver 4.5), the same problem existed with <CFIF>.
> Here's an
> example. Say that the parameter "strFoo" doesn't exist, consider the
> following code:
>
> <cfif isDefined("strFoo") and len(trim(strFoo))>
> ... blah blah blah ...
> <cfelse>
> ... blah2 blah2 blah2 ...
> </cfif>
>
> In the past, ColdFusion would choke on the CFIF statement when
> "strFoo" was
> not defined, even though you'd expect it to immediately jump to the CFELSE
> statement once the isDefined() returned false. I believe this was fixed
> with the release of ColdFusion 4.5 - I might be wrong on the
> version number.
>
> My guess is that this behavior is still leftover in the iif() function.
> I've noticed this in my own development as well that I never seem
> to be able
> to use an isDefined() check in an iif() block. Doing so always results in
> the "Error resolving parameter" error.
>
> A workaround would be to set a default for the variable using CFPARAM and
> then changing your iif() logic. Here's an example:
>
> <cfparam name="attributes.order" default="">
> <cfset orderString =
> iif(len(trim(attributes.order)),de("&order=#attributes.order#"),"")>
> <cflocation url="index.cfm?fuseaction=tools#orderString#">
>
> Hope this helps,
> Tyson
>
> -----Original Message-----
> From: Brent Goldman [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 29, 2001 7:36 PM
> To: CF-Talk
> Subject: IIF and DE
>
>
> Hi,
>
> I'm trying to use IIF with DE, and it doesn't seem to be working.
> My code:
> <cfset orderString = iif(isDefined("attributes.order"),
> DE("&order=#attributes.order#"), "")>
> <cflocation url="index.cfm?fuseaction=tools#orderString#>
>
> What I am trying to do is this: if a certain variable is defined
> (attributes.order), then create a string that can be appended to a URL,
> otherwise make the string blank.
> The desired results:
> - If attributes.order is set to "name", then orderString
> should be set to
> "&order=name"
> - If attributes.order is undefined, then orderString should be
> set to ""
>
> The problem is that when attributes.order is undefined, ColdFusion still
> tries to execute the code that should be executed if the first expression
> was true, thus giving an error. CF is trying to find the value of
> attributes.order in the DE("&order=#attributes.order#")
> statement, even
> though attributes.order is undefined, and that statement should go with
> being evaluated.
>
> This problem is kinda hard to explain, but does anyone have any
> idea on how
> to fix this??? (without having to use CFIF/CFELSE - the whole
> point is that
> I want to use IIF and DE)
>
> Thanks
> -Brent
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Structure your ColdFusion code with Fusebox. Get the official book at
http://www.fusionauthority.com/bkinfo.cfm
FAQ: http://www.thenetprofits.co.uk/coldfusion/faq
Archives: http://www.mail-archive.com/[email protected]/
Unsubscribe: http://www.houseoffusion.com/index.cfm?sidebar=lists
