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Using Mutable Values
f#

Hi

I'm back with more questions. I thought I understood mutable values, but I must be wrong because a very simple code sample wont seem to work. Heres whats happening: I want to make a function that counts the number of times that it is called. I have written the following: 

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#light 

let mutable theCount = 0 

let count = 
  do theCount <- theCount + 1
  theCount 


let Test1 = 
  count = 1 

let Test2 = 
  count = 2 

let Test3 = 
  count = 3 

do print_any [Test1; Test2; Test3]

Now what I am expecting is to get [true; true; true;] but what I am getting is [true; false; false;] which indicates that the first increment (from 0 to 1) is working, but not the rest. And the million dollar question is .. why?

As always, any and all help, greatly appreciated
Matt

.

It's just a small error - you should make count a function, at the moment it is a value so bind only happens once. I think what you meant to right is:

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#light 
let mutable theCount = 0 
let count() =   
    theCount <- theCount + 1  
    theCount
     
let Test1 =   
    count() = 1   
let Test2 =   
    count() = 2   
let Test3 =   
    count() = 3 

print_any [Test1; Test2; Test3]

Cheers,
Rob

By on 8/12/2007 3:46 AM ()

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