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Choose while function

A function that is like 'Seq.choose' but stops producing values as soon as the first 'None' value is produced.

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let chooseWhile f (input:seq<_>) = 
  seq { use en = input.GetEnumerator()
        let mutable finished = false
        while not finished do
          if en.MoveNext() then 
            match f en.Current with
            | None -> finished <- true
            | Some v -> yield v
          else  
            finished <- true }
val chooseWhile : f:('a -> 'b option) -> input:seq<'a> -> seq<'b>

Full name: Script.chooseWhile
val f : ('a -> 'b option)
val input : seq<'a>
Multiple items
val seq : sequence:seq<'T> -> seq<'T>

Full name: Microsoft.FSharp.Core.Operators.seq

--------------------
type seq<'T> = System.Collections.Generic.IEnumerable<'T>

Full name: Microsoft.FSharp.Collections.seq<_>
val en : System.Collections.Generic.IEnumerator<'a>
System.Collections.Generic.IEnumerable.GetEnumerator() : System.Collections.Generic.IEnumerator<'a>
val mutable finished : bool
val not : value:bool -> bool

Full name: Microsoft.FSharp.Core.Operators.not
System.Collections.IEnumerator.MoveNext() : bool
property System.Collections.Generic.IEnumerator.Current: 'a
union case Option.None: Option<'T>
union case Option.Some: Value: 'T -> Option<'T>
val v : 'b
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More information

Link:http://fssnip.net/7Oz
Posted:1 years ago
Author:Tomas Petricek
Tags: sequences