Re: [CFCDev] How should I define variable in a CFC?

Matt Liotta Tue, 10 Feb 2004 18:20:13 -0800

It would handle it just fine, but your Duplicate() call is expensive. Also, having additional nested structs makes things quite messy indeed.

-Matt

On Feb 10, 2004, at 6:12 PM, Raymond Camden wrote:

I'm late to this thread, but what is wrong with this:

<cffunction ....>
        <cfset var tempStruct = "">
        <cfset var data = arrayNew(1)>
        <cfset var x = 1>

        <cfloop index="x" from=1 to=10>
                <cfset tempStruct = structNew()>
                <cfset tempStruct.foo = "moo">
                <cfset arrayAppend(data,duplicate(tempStruct))>
        </cfloop>

Won't this handle it just fine?

======================================================================= ==== Raymond Camden, ColdFusion Jedi Master for Mindseye, Inc (www.mindseye.com) Member of Team Macromedia (http://www.macromedia.com/go/teammacromedia)

Email    : [EMAIL PROTECTED]
Blog     : www.camdenfamily.com/morpheus/blog
Yahoo IM : morpheus

"My ally is the Force, and a powerful ally it is." - Yoda

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Matt Liotta
Sent: Tuesday, February 10, 2004 5:09 PM
To: [EMAIL PROTECTED]
Subject: Re: [CFCDev] How should I define variable in a CFC?

Interesting! I have also found that variables created in
loops are a big problem. For example, suppose you want to
create an array of structures. You write a loop that creates
a structure, assigns some keys, and then appends the
structure to the array. How do you declare the structure as
local to that function? Well you can't without resorting to
some drastic measures.

-Matt

On Feb 10, 2004, at 6:00 PM, Nathan Dintenfass wrote:

From the informal testing I have done, you don't need to

worry about

that.
CFQUERY will overwrite the cfquery variable every time a

query is run.

 In
fact, from what I've seen, doing what you suggest with "var

cfquery"

doesn't
even work to keep the "cfquery" variable local to the method.  For
instance:

<cfcomponent>
<cffunction name="getEmployees">
        <cfset var get = "">
        <cfset var cfquery = "">
        <cfquery name="get" datasource="cfsnippets">
                select  *
                from    employees
        </cfquery>
        <cfreturn get>
</cffunction>
<cffunction name="getLastExecutionTime">
        <cfreturn cfquery.executionTime>
</cffunction>
</cfcomponent>

If you call getEmployees() and then getLastExecutionTime()

you still

get the time of the query. To make things even stranger,

if you add

this line of code inside getEmployees after the query:

<cfset writeOutput(cfquery.executionTime)>

it won't work unless you get rid of the var statement with cfquery.

Funky.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Jay Gibb
Sent: Tuesday, February 10, 2004 2:39 PM
To: [EMAIL PROTECTED]
Subject: RE: [CFCDev] How should I define variable in a CFC?
Hey Barney,

In your example below wouldn't you also need..

<cfset var cfquery = "">
So that the cfquery structure returned by the <cfquery> tag didn't
get dumped into the shared variables scope?
- j.

P.S. Pardon my re-iterating over this question, but it

still confuses

me.

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Barney Boisvert
Sent: Tuesday, February 10, 2004 11:04 AM
To: [EMAIL PROTECTED]
Subject: RE: [CFCDev] How should I define variable in a CFC?

Yeah, you have to define everything first. And you have

to set them

all to a value as well.  You can reasign later, though, and the
variable name is still protected.  This comes in very handy with
queries:

<cffunction name="getlist">
  <cfset var get = "" />
  <cfquery name="get" datasource="#variables.my.dsn#">
    SELECT *
    FROM myTable
    ORDER BY name
  </cfquery>
  <cfreturn get />
</cffunction>

You should do that for ALL queries, even if you don't need

to use the

name afterwards (for insert, update and/or delete queries).
Cheers,
barneyb
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Schreck,

Thomas (PPC)

Sent: Tuesday, February 10, 2004 10:57 AM
To: [EMAIL PROTECTED]
Subject: RE: [CFCDev] How should I define variable in a CFC?
That makes sense, but it seems somewhat limiting. What

happens as

you process through the logic of your method and you need

to set the

value of a variable? By declaring the variable with var

at the top,

is it still protected further in your code? I assume so

given your

answer (I think I answered my own question). So, you

must know all

variables you want protected prior to getting into your method
logic, correct?

Tom


-----Original Message-----
From: Nathan Dintenfass [mailto:[EMAIL PROTECTED]
Sent: Tuesday, February 10, 2004 12:45 PM
To: [EMAIL PROTECTED]
Subject: RE: [CFCDev] How should I define variable in a CFC?

As the error says, you can only use var at the beginning of a
method ;)

In other words, you can only declare your local variables

immediately

after
CFARGUMENT and before any other code.  Though, in 6.1 you

can declare

them
at the top of the first CFSCRIPT block inside the function
body (a nice
improvement, as you had to use CFSET for all var declarations in
6.0).

-----Original Message-----
From: [EMAIL PROTECTED]

[mailto:[EMAIL PROTECTED]

Behalf Of Schreck, Thomas (PPC)
Sent: Tuesday, February 10, 2004 10:37 AM
To: [EMAIL PROTECTED]
Subject: RE: [CFCDev] How should I define variable in a CFC?

I've run into situations trying to use 'var' in front of

a variable

name
and it produces an error. Something to the affect "var

can only be

used
at the beginning of a method". What are the rules

around using var?

Thanks - Tom Schreck
-----Original Message-----
From: Barney Boisvert [mailto:[EMAIL PROTECTED]
Sent: Tuesday, February 10, 2004 12:02 PM
To: [EMAIL PROTECTED]
Subject: RE: [CFCDev] How should I define variable in a CFC?
Using the 'var' keyword is only allowed inside
functions/methods. It
creates a local variable that only exists for that specific
invocation
of
the function.  Such variables are immune to race

conditions, because

they
are bound to a specific invocation.  This is not specific

to CFCs, you

can
use it in any function definition (including CFSCRIPT

functions), in

or
outside a CFC.

Using the 'variables' scope creates a private variable
accessible only
to
your CFC.  It exists as long as the instance of the CFC

is around.

Such
variables are NOT immune to race conditions, because

they are shared

across
the instance, and multiple clients may be calling methods

on a single

instance at the same time.

Using the 'this' scope is just like the 'variables' scope,

except that

the
variables are public, so the can be read or written by

client code, as

well
as methods of the CFC.

Cheers,
barneyb

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Troy Simpson
Sent: Tuesday, February 10, 2004 9:38 AM
To: [EMAIL PROTECTED]
Subject: [CFCDev] How should I define variable in a CFC?

All,

I have been away from coldfusion for about a year or so and
now need to
get back into in.  I am using ColdFusion MX for this project
that I am
working on.  I need some clarification if possible.

How should I define variables in a CFC and why?
What is the difference between the three?

<cfcomponent>
   <cfset var dsn = "DataSourceName">
   <cfset variables.dsn = "DataSourceName">
   <cfset this.dsn = "DataSourceName">
</cfcomponent>

Thanks,
Troy

--
Troy Simpson
   Applications Analyst/Programmer, OCPDBA, MCSE, SCSA
North Carolina State University Libraries
Campus Box 7111 | Raleigh | North Carolina
ph.919.515.3855 | fax.919.513.3330
E-mail: [EMAIL PROTECTED]

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Re: [CFCDev] How should I define variable in a CFC?

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