F#: operator precedence

Question

This code doesn't compile:

let f (x:byte) = printfn "%d" x

let b = int 'a'
f(byte <| b ||| 0x1)

(4,17): error FS0001: This expression was expected to have type
    byte
but here has type
    int

• http://ideone.com/C6KoCQ

The F# operator table states the backward pipe operaotor (<|) which has a form of (< op) has a lower precedence than the bitwise or operator (|||) :

• http://msdn.microsoft.com/en-us/library/dd233228.aspx

So I thought (byte <| b ||| 0x1) should be parsed as (byte <| (b ||| 0x1)) . But the compiler error message suggests it is parsed as ((byte <| b) ||| 0x1) . What's happening here?

Answer 1

I just had a look at the FSharp specs and there <| indeed has higher precedence than ||| (if I read the table right)

So most likely it's either an error in the MSDN docs or it was changed and not updated.

It's on page 35: