Avoiding Evaluate

[perezle]

I'm starting with a formula, which is a string, in a variable. For example,
calcFormula = (a + b) / c. I replace parts of the string with numeric values
so that I end up with calcFormula's value being something like this: (2 + 4) / 2

I need to calculate the value of calcFormula now. Is there another way to do
this besides the below?
calcValue = Evaluate("#calcFormula#")

[OldCFer]

Normally you would just set the a, b, and c values, then use:
<cfset calcValue = (a + b) / c>

[perezle]

I don't know the structure of the formula until the page loads, so I don't know
if I have an a or b or what beforehand. Replacing all parts of the formula at
the end would be trickier. I'd prefer to replace incrementally. Any other
ideas?

[Adam Cameron]

> I don't know the structure of the formula until the page loads, so I don't know

> if I have an a or b or what beforehand. Replacing all parts of the formula at
> the end would be trickier. I'd prefer to replace incrementally. Any other
> ideas?

I'm usually the first person to say "don't use evaluate() if at all
possible", but this is case, it's the correct tool for the job (IMO).
--

Adam

[MikerRoo]

As Adam said,

This is an instance when evaluate is appropriate. Your alternative is to
write an equation parser -- which can be fun but the boss might not understand.

Be sure to wrap the result in HTMLEditFormat or use some other means to guard
against cross-site scripting attacks.