It is highly recommended that users new to jupyter/ipython take the User Interface Tour from the toolbar above (Help -> User Interface Tour).
This notebook introduces the IPython widgets, as implemented in IHaskell. The
Buttonwidget is also demonstrated as a live action example.
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{-# LANGUAGE OverloadedStrings #-}
import IHaskell.Display.Widgets
The module can be imported unqualified. Widgets with common names, such as Text, Image etc. have a -Widget suffix to prevent name collisions.
Each widget has different properties, but the surface level API is the same.
Every widget has:
IO <widget> value/function of the form mk<widget_name>.setField and getField.The setField and getField functions have nasty type signatures, but they can be used by just intuitively understanding them.
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:t setField
The setField function takes three arguments:
FieldField
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:t getField
The getField function takes a Widget and a Field and returns the value of that Field for the Widget.
Another utility function is properties, which shows all properties of a widget.
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:t properties
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-- Showables
1 + 2
"abc"
Widgets can either be displayed this way, or explicitly using the display function from IHaskell.Display.
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import IHaskell.Display
:t display
A widget can be displayed multiple times. All these views are representations of a single object, and thus are linked.
When a widget is created, a model representing it is created in the frontend. This model is used by all the views, and any modification to it propagates to all of them.
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:t closeWidget
Let's play with buttons as a starting example:
As noted before, all widgets have a constructor of the form mk<Widget>. Thus, to create a Button, we use mkButton.
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button <- mkButton -- Construct a Button
:t button
Widgets can be displayed by just entering them into a cell.
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button -- Display the button
To view a widget's properties, we use the properties function:
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-- The button widget has many properties.
properties button
Let's try making the button widget wider.
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-- 250 pixels wide
setField button Width 250
There is a lot that can be customized. For example:
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setField button Description "Click Me (._.\")"
setField button ButtonStyle SuccessButton
setField button BorderStyle RidgeBorder
setField button BorderWidth 20
setField button BorderRadius 30
setField button Padding 10
setField button Height 125
setField button FontFamily "cursive"
setField button FontSize 30
The button widget also provides a click handler. We can make it do anything, except console input. Universally, no widget event can trigger console input.
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setField button ClickHandler $ putStrLn "fO_o"
button -- Displaying again for convenience
Now try clicking the button, and see the output. If we try to do console input, an error occurs.
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setField button ClickHandler $ getLine >>= putStrLn