ExtraTopLevelOperators.Lazy<'T> Active Pattern (F#)
An active pattern to force the execution of values of type Lazy.
Namespace/Module Path: Microsoft.FSharp.Core.ExtraTopLevelOperators
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
( |Lazy| ) : Lazy<'T> -> 'T
Parameters
- input
Type: Lazy<'T>
Remarks
This function is named LazyPattern in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.
Example
The following code illustrates the use of the Lazy active pattern.
let rec factorial n = match n with 0 | 1 -> 1 | n -> n * (factorial (n-1))
let lazyValue = lazy ( factorial (10) )
// No computation occurs until the match expression executes.
match lazyValue with
| Lazy value -> printfn "10 factorial is %d" value
Output
10 factorial is 3628800
Platforms
Windows 7, Windows Vista SP2, Windows XP SP3, Windows XP x64 SP2, Windows Server 2008 R2, Windows Server 2008 SP2, Windows Server 2003 SP2
Version Information
F# Runtime
Supported in: 2.0, 4.0
Silverlight
Supported in: 3