So I went back and read the docs for IIF. I haven't looked at them in years and I'm shocked that I've used it for SOOOOO many years without really knowing exactly how it worked. I would've first read about IIF pre version 5. I can't even find the docs for it. Version 5's description is a little vague. You learn something new every day I guess. That's awesome. Thanks again Rex.
On Tue, Sep 7, 2010 at 8:49 PM, Michael Grant <[email protected]> wrote: > Wow. I had no idea you could wrap DE in Evaluate. Did you come figure this > out through trial and error or have I just never read it? > > Thanks for the post rex. > > > On Tue, Sep 7, 2010 at 8:34 PM, rex <[email protected]> wrote: > >> >> A lot of people get DE() wrong. >> >> IIF does not short-circuit >> (http://en.wikipedia.org/wiki/Short-circuit_evaluation), meaning that >> your DE() gets evaluated even if the condition is FALSE. So, this will >> break: >> #iif(false, notFalse, false)# >> since notFalse does not exist. Same here: >> #iif(true, true, fols)# >> since fols does not exist. And finally your code: >> #iif(false, DE(x.classAssign["#y#head"]), DE(''))# >> breaks since x.classAssign["NAMEhead"] does not exist. >> >> DE evaluates a STRING parameter and finds double-quotes. If you pass in >> a variable, it looks for the value of that variable. Since you are >> passing x.classAssign["#y#head"], it looks for x.classAssign["NAMEhead"] >> and breaks. >> >> This will work: evaluate(DE("x.classAssign['#y#head']")) - notice the >> single-quotes surrounding #y#head! This is because we don't want DE to >> escape this, so we don't want to wrap it around double-quotes! >> >> Here is the code (I used "no value" instead of "", but it's still the >> same code that you use): >> >> <cfset x.classAssign = { >> NameHead = "this head", >> NoNameHead = "that head" >> } /> >> <cfoutput> >> <cfset y = "Name" /> >> #iif(StructKeyExists(x.classAssign,"#y#head"), >> evaluate(DE("x.classAssign['#y#head']")), DE("no value"))#<hr /> >> <cfset y = "NoExist" /> >> #iif(StructKeyExists(x.classAssign,"#y#head"), >> evaluate(DE("x.classAssign['#y#head']")), DE("no value"))#<hr /> >> >> <cfset Y = 'Any' /> >> See how these two differ: <br /> >> #DE("x.classAssign['#y#head']")#<br /> >> #DE('x.classAssign["#y#head"]')# >> </cfoutput> >> >> Michael Grant wrote: >> > HA! So I'm not the only one! >> > So I thought DE meant "Delay Evaluation" as in "Don't evaluate what's in >> > these little brackets this until you've satisfied the IIF condition." >> > >> > >> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Order the Adobe Coldfusion Anthology now! http://www.amazon.com/Adobe-Coldfusion-Anthology-Michael-Dinowitz/dp/1430272155/?tag=houseoffusion Archive: http://www.houseoffusion.com/groups/cf-talk/message.cfm/messageid:336889 Subscription: http://www.houseoffusion.com/groups/cf-talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/groups/cf-talk/unsubscribe.cfm
