MakeBoxes

Wolfram Kernel

Execution environment

MakeBoxes[expr_, form_]

an output handler expression acting as UpValues for other expression converts it to a decorated form, which is then rendered by an editor.

MakeBoxes is applied only to the output expressions in a normal Wolfram cells, Slides and WLX. It will not affect any intermediate operations.

info

MakeBoxes[..., StandardForm] is applied to any visible output from the cell. It is also a part of a pipeline for ToString[..., StandardForm] used in CellPrint, and EditorView for various applications.

Supported forms

• StandardForm
• WLXForm

Used together with

• BoxBox
• ViewBox
• InterpretationBox

Applications

It is a core concept of the Notebook interface

Creating interactive objects

Used by

• Graphics
• Graphics3D
• ListLinePlotly
• Plotly
• EventObject
• many more

All graphics and interactive objects are running on WLJS interpreter, which is browser'a minimal Wolfram Language interpreter running on Javascript. It draws graphics, handles users interaction via JS. To explicitly run an expression on browser's side you need to apply CreateFrontEndObject. This is done automatically using MakeBoxes

for example

...
ListLinePlotly /: MakeBoxes[ListLinePlotly[args__], StandardForm] := With[{o = CreateFrontEndObject[ListLinePlotly[args]]}, 
	MakeBoxes[o, StandardForm]
]

ListPlotly /: MakeBoxes[ListPlotly[args__], StandardForm] := With[{o = CreateFrontEndObject[ListPlotly[args]]}, 
	MakeBoxes[o, StandardForm]
]
...

Styling symbols

Please consider to use StandardForm for form argument to achieve those effects.

See ViewBox and BoxBox

Data preview

One can make a preview of the data for example

dataHolder /: MakeBoxes[dataHolder[data_], StandardForm] := With[{
  display = ListPlot[data, ImageSize->200, Axes->False, ImagePadding->None] // CreateFrontEndObject
},
	InterpretationBox[MakeBoxes[display, StandardForm], data]
] 

dataHolder /: ListLinePlot[d_dataHolder, opts___] := ListLinePlot[d//First, opts]

dataHolder[RandomReal[{-1,1}, 100]]

dataHolder[RandomReal[{-1,1}, 100]] // ListLinePLot

info

ViewBox is more performant compared to InterpretationBox, when it comes to replacing symbols with Graphics or other interactive objects.

tip

For just a one-time decoration - use Interpretation