[thelist] ColdFusion: Nested pound signs

[judah at wiredotter.com]

At 04:46 PM 11/13/2001 -0600, you wrote:
>I mean, nesting pound signs, as in:
><CFSET Sentence = "The length of the full name is #Len("#FirstName#
>#LastName#")#">
>
>Look at the bottom of this page:
>http://www.advances.com/cfdocs/lang/lr010005.htm

They tell you the correct information near the bottom of the 
page:  basically, never nest pound signs.  As an interpreted language, CF 
parses a document looking for things it can identify as a variable, and 
then converting it to its value.  As a general rule, if a string is inside 
of a CF tag (such as cfset), the string will be treated as a variable 
unless specifically demarcated as a string by encasing it in either single 
or double quotes.

Example:

><CFSET Sentence = "The length of the full name is #Len("#FirstName#
>#LastName#")#">

Can be written as <cfset sentence = 'The length of the full name is ' & 
Len(FirstName&' '&LastName)>

In this case, the single quotes around The length of the full name is tells 
CF that its a string and should not be evaluated.  The ampersand is a 
concatenation operand that sticks the final evaluated product of the right 
hand side onto the string on the left hand side.

Since Len is inside a cfset and not inside of quotes, CF checks it and sees 
that its a function.  Since FirstName and LastName are inside a Len 
function and not enclosed in quotes, they are treated as variables.  And 
the &' '& concatenates the evaluated values of FirstName and LastName with 
a string literal space stuck in between.

Pretty much the only time you need to wrap something in pound signs is when 
you want to output the contents of a variable that resides within a mass of 
text, such as:

<cfset myname = "Judah">

<cfoutput>
Hi, my name is #myname#.  I like bananas.  Eek, Eek.
</cfoutput>

The only times I can think of that you need pound signs with a CF tag are 
when you are using a variable while looping over a list or a structure.

<cfset mystuff = "one,two,three,four">
<cfloop index="stuff" list="#mystuff#">
         <cfoutput>#stuff#<br></cfoutput>
</cfloop>

I hope this helps,

Judah