Hi Brian,

F# does not allow direct manipulation of an application stack like Forth. However there are some techniques that are quite similar between the languages.

Hope this helps,

Phil

Interactive Mode
Both Forth and F# have interactive modes that can be used for scripting.

Operators
In both Forth and F# operators can be used like functions:

• Forth: 1 1 +
• F#: (+) 1 1

Currying

Function parameters can be ommited:

• Forth: : Inc ( n -- n ) 1 + ;
• F#: let Inc = (+) 1

Passing left to right

F# defines a pipe forward operator (|>) as let inline (|>) x f = f x

• Forth: 1 Inc
• F#: 1 |> Inc

Recursion

Both F# and Forth support explicit recursive function definitions:

• Forth: recursive keyword
• F#: rec keyword

Sample

Putting all the techniques together in F# we can sum a list of integers like so:

1
2
3
4
5
6
7

let rec fold f acc = function   
    | [] -> acc    
    | x::xs -> fold f (f acc x) xs
 
let sum = fold (+) 0
 
[1;2;3] |> sum