Custom display printers

Custom display printers can be added during runtime based off of type. Example for providing a custom display printer for float to display a pink div:

1: 
2: 
3: 
4: 
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App.AddDisplayPrinter(fun (x:float) ->
    {
        ContentType = "text/html"
        Data = "<div style=\"background-color: pink\">" + x.ToString() + "</div>"
    }
)

To invoke the printer:

1:	1.0 \|> Display

Will render

Custom fsi printers

Similarly, FSI printers can be added which can provide display a string for a type. However, a more complex implementation could send display data directly to the client as a side-effect, which will skip the need for calling the Display function directly from the notebook. Example:

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App.AddFsiPrinter(fun (x:float) ->
    App.Kernel.Value.SendDisplayData("text/html", "<div style=\"background-color: pink\">" + x.ToString() + "</div>")
    x.ToString()
)

Now, executing a cell with the following code:

1:

1.0

Will render as:

However, executing a cell with the following code:

1:	[1.0; 2.0; 3.0;]

Will render as:

module App

from IfSharp.Kernel

val AddDisplayPrinter : (('a -> BinaryOutput) -> unit)

Full name: IfSharp.Kernel.App.AddDisplayPrinter

val x : float

Multiple items
val float : value:'T -> float (requires member op_Explicit)

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

--------------------
type float = System.Double

Full name: Microsoft.FSharp.Core.float

--------------------
type float<'Measure> = float

Full name: Microsoft.FSharp.Core.float<_>

namespace Microsoft.FSharp.Data

System.Double.ToString() : string
System.Double.ToString(provider: System.IFormatProvider) : string
System.Double.ToString(format: string) : string
System.Double.ToString(format: string, provider: System.IFormatProvider) : string

val Display : ('a -> unit)

Full name: IfSharp.Kernel.Globals.Globals.Display

val AddFsiPrinter : (('a -> string) -> unit)

Full name: IfSharp.Kernel.App.AddFsiPrinter

val mutable Kernel : Option<IfSharpKernel>

Full name: IfSharp.Kernel.App.Kernel