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Ben Nadel at CFCamp 2023 (Freising, Germany) with: Mark Drew
Ben Nadel at CFCamp 2023 (Freising, Germany) with: Mark Drew ( @markdrew )

I Finally Used CFParam Type = "VariableName"

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I am a HUGE fan of ColdFusion's CFParam tag. I use it, I think, in a more extensive way than most people - both to enforce variable existence and to validate its data type. CFParam allows for many useful types of data type validation, including basic data types such as string, numeric, array, and struct. One type that has always struck me as weird was the type "VariableName".

I could never quite figure out why anyone would ever need to enforce a valid ColdFusion variable name. But then, yesterday, when I was working on my ColdFusion custom tag for looping over regular expression pattern matches, I had a light-bulb moment! Many ColdFusion tags (ex. CFFile, CFDirectory, CFImage, CFQuery) let you store returned data into a named variable. For example, when you run a query, the resultant record set gets stored in a variable defined by the Name attribute. All of these attributes (Name, Result, Variable) need to be valid ColdFusion variable names!

That's when all of this realization came rushing to me - any time you need to store data into a user-defined variable (as I was doing in my custom tag), you need to enforce that the value given is actually a valid ColdFusion variable name.

Of course! It's so obvious, now :)

Reader Comments

15,640 Comments

@Ray,

The one that I have really leeched onto is the IsValid( "email", FORM.email ). I used to write my own email validation function, which would fail occasionally cause people have some crazy email addresses. Luckily, IsValid( "email" ) is so much more reliable.

15,640 Comments

@Pete,

Cool tip. I never thought of using that to help enforce logic that was necessarily FOR a variable name, but rather for values that mimic those requirements. Sweet idea.

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Ben Nadel