Function Syntax and placement

[strudleman]

**Disclaimer** I've been around scripting and databases for years(PHP, Perl, Oracle, MySQL, etc) but I've been working with FM Pro Advanced 12 for just a few days now.  I apologize for what I'm sure will turn out to be the dumbest question of the year.

 

I have a piece of equipment which costs '$cost'

I have an equipment lifespan which is '$years'

I have a static cost inflation rate which is 2.5%

I have a field which is supposed to estimate the cost of replacing this item at the end if it's lifespan, and that value needs to be automagically populated.

 

This pseudo code will hopefully explain what I'm trying to do:

 

$cost = cost;
$years = years;
while ($years != 0){
   $years - 1;
   $cost = $cost * 1.025 //That adds 2.5% to the cost

};

 

 

This function just adds 2.5% to the cost of replacement for this item.  Every year, it adds another 2.5% to the previous years cost.

 

My question is.. where do I put it?  In the calculation field? A custom function or a script? (I will have to use this on multiple tables)

And once I know where to put it, what's the syntax for it going to look like?  

 

Thanks everyone.  This is my first post here on this forum, but with any luck I'll be around a while.  I'm really enjoying the FM experience so for

 

[Ocean West]

A custom function would be the place for this, this is a recursive function 

 

 

 

EquipValue ( cost ; lifespan ) 

 

Let ( 
[
inflation = cost * 1.025 // adds fixed 2.5% to cost
];

Case ( lifespan = 0  ;

inflation + EquipValue ( cost ; lifespan - 1 ) 


))

 

Does the inflation rate ever change? If so you could add that as a parameter and then in the calculation or script where this is referenced you can

provide that value.

 

 

EquipValue ( cost ; lifespan ; rate )   replace the 1.025 in the formula above with the rate. 

 

inflation = cost * rate // rate value provided by script or runtime calculation

 

if this function is used in calculation and the you change the rate here it would affect ALL instances in all tables where this is used.

you may want to add this to an auto enter calculation and allow it to change if the other reference fields are changed - so that

if you do change the rate it would not affect historical records. ( unless that is acceptable to your solution business logic ) 

 

 

hope this helps, and welcome to the forums! 

 

stephen

[comment]

How about some simple math?

 

Cost * ( 1 + Rate )^Years

 

 

 

My question is.. where do I put it?  In the calculation field? A custom function or a script? (I will have to use this on multiple tables)

 

You would put this inside the definition of a calculation field. I don't see why you would have to use this in multiple tables - sounds like you need to re-examine your data structure.

[Ocean West]

  schooled! 

[strudleman]

Ocean West, thanks for the detailed reply and comments.  That's exactly what I was looking for!

 

But I can't deny the elegant simplicity in Comments solution.  That's just fantastic.