This is a proof of concept to see how hard it would be to write a code editor that
- Is native (WPF), no html/javascript: I really like the idea behind Brackets/Atom but here I want things blazing fast
- Embeded terminal to be able to run command within the editor
- Embeded file watcher that could trigger custom command line scripts
- Multi-rows of tabs, I love tabs, I open a lot of them, I don't like to scroll tabs !
#Why Why am I writing my own code editor ?
- It's a fun exercise (learn some f#,frp,wpf)
- I like to learn different programming lanugages but I have not yet found lightweight windows code editor
- Lightweight to me mean: fast to start, reactive UI, bare minimun features
- I want multi row tabs
- I want an embeded command shell
- I want to be able to trigger script on file change and set that up EASILY
This is where we have a fun and see how the baby is growing 😃
- Coded up a parens/brackets matcher, this is a missing feature in avalon edit
- Code for the matcher will need some cleaning, will try to implement parser combinator instead / fsharp workflow
- More optimz, I've switched the console from a textbox to an avalon edit control. This will enable better throughtput and syntax highlighting !
- Optimized the diffing algo, things are now fast again but still some locking there and there that will need some investigation
- Added some icons for folders
- Refactored diffing algo to take into account events subscriptions
- New algo is much more slower so will need too optimize
- Tree File browser fixed but will need more visual design :p
- Skining (Thanks to awesome project mahapps )
- Refactoring, extracted WPF setup code from F# to C#
- Bug fixes
- Tree diffing optimisations
Don't like the look and feel of the grid splitter. Tree browser still not fixed :p
- Ability to close tabs (Thanks to fsxaml, it's a real pleasure to work with static xaml in fs)
- Ability to search text
- Monokai theme (Elm only, hard coded)
- Elm syntax
- Build on save (Hard coded)
Folder browser is broken, will fix in next version
I've now reached the point where I should be able to start using this thing and write some code 😃
Mainly a lot of refactoring, I've replaced most of the c# code to f# code. All the meat is now in ui.fsx I'll remove soon all legacy c# code once I'll have migrated the terminal.
The architecture is now FRP:
- a state for the whole application
- a function that handle events using a fold on the state
- a renderer that turn the state into a virtual DOM representation of the app
- a solver that will diff the previous DOM and the current DOM into WPF code
This is inspired by Elm and React.js FRP is implemented thanks to Reactive extensions
I'm really happy to be able to run away from event handlers, data binding and XAML !
This is how the view code looks like now:
let ui (state:EditorState) =
let tabs = state.openFiles |> List.map (fun (t,p,pos,selected) -> TabItem (t,Editor (p,pos),selected ) )
Dock [Docked(Menu [MenuItem ("File",
[
MenuItem ("Open file",[], [BrowseFile] )
MenuItem ("Open folder",[], [BrowseFolder])
MenuItem ("Save",[], [SaveFile])], [])],Dock.Top)
Grid ([GridLength(1.,GridUnitType.Star);GridLength(5.);GridLength(2.,GridUnitType.Star)],[],[
Column(Tree [TreeItem("Code",[TreeItem("HelloWorld",[])])] ,0)
Column(Splitter Vertical,1)
Column(
Grid ([GridLength(1.,GridUnitType.Star)],[GridLength(1.,GridUnitType.Star);GridLength(5.);GridLength(1.,GridUnitType.Star)],
[
Row(Tab tabs,0)
Row(Splitter Horizontal,1)
Row(Terminal,2)
]),2)
])
]Compare this to the hundred of xaml code !
<Window x:Class="MyEdit.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:t="clr-namespace:Simple.Wpf.Terminal;assembly=Simple.Wpf.Terminal"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
Title="MainWindow" Height="350" Width="525" WindowStyle="ToolWindow" WindowState="Maximized">
<DockPanel LastChildFill="True" Background="{StaticResource BackgroundKey}" >
<Menu DockPanel.Dock="Top" >
<MenuItem Header="_File">
<MenuItem Header="_Open" Command="{Binding Path=OpenFile, Mode=OneWay}"/>
<MenuItem Header="_Open Folder" Command="{Binding Path=OpenFolder, Mode=OneWay}"/>
<MenuItem Header="_Close"/>
<MenuItem Header="_Save"/>
</MenuItem>
</Menu>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" ></ColumnDefinition>
<ColumnDefinition Width="5" ></ColumnDefinition>
<ColumnDefinition Width="2*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<TreeView Grid.Column="0" Name="trvMenu" ItemsSource="{Binding Tree}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate DataType="{x:Type MenuItem}" ItemsSource="{Binding Items}">
<TextBlock Text="{Binding Title}" />
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedItemChanged">
<i:InvokeCommandAction Command="{Binding TreeviewSelectedItemChanged}"
CommandParameter="{Binding ElementName=trvMenu, Path=SelectedItem}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</TreeView>
<GridSplitter
Grid.Column="1"
VerticalAlignment="Stretch"
HorizontalAlignment="Center"
ResizeDirection="Columns"
ShowsPreview="True" Width="5" Cursor="SizeWE" />
<Grid Grid.Column="2">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="5" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<TabControl ItemsSource="{Binding PageModels, Mode=TwoWay}">
<TabControl.ItemContainerStyle>
<Style TargetType="TabItem">
<Setter Property="Header" Value="{Binding TabCaption, Mode=TwoWay}"/>
<Setter Property="Content" Value="{Binding TabContent}"/>
<Setter Property="IsSelected" Value="{Binding IsSelected}"/>
</Style>
</TabControl.ItemContainerStyle>
</TabControl>
<GridSplitter
Grid.ColumnSpan="1"
Grid.Row="1"
VerticalAlignment="Center"
HorizontalAlignment="Stretch"
ResizeDirection="Rows"
ShowsPreview="True" Height="5" Cursor="SizeNS" />
<t:Terminal Grid.Row="2" Grid.Column="0" x:Name="TerminalOutput"
IsReadOnlyCaretVisible="False"
VerticalScrollBarVisibility="Visible"
IsReadOnly="false"
FontFamily="Consolas"
Prompt=">"
ItemsSource="{Binding Path=Items, Mode=OneWay}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LineEntered">
<i:InvokeCommandAction Command="{Binding Path=ExecuteItemCommand, Mode=OneWay}"
CommandParameter="{Binding Path=Line, Mode=OneWay, ElementName=TerminalOutput}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</t:Terminal>
</Grid>
</Grid>
</DockPanel>
</Window>- Added ability to save file
- We now display an '*' when the file is modified and not saved
- Added a toolbar (stole that from avalon edit sample)
###My feeling Codewise things are really starting to get out of hand. The more component I add the more it's starting to get difficult to find my way in all the event handling and data binding.
It's funny to see how fast you can get started and how fast thing get quickly ugly :D
I'll now try to spend more time refactoring the code and see if I can introduce some FRP for my own sanity. I want to be able to clearly see:
- My data model
- The events
- How the ui is built from that
Some resource on WPF and FRP http://steellworks.blogspot.com/2014/03/tutorial-functional-reactive.html
Now I can open a folder and expand sub folders. Clicking on a file opens it the currently selected tab.
- Really poor but we start to get a feel of multirows tabs
- Tree File browser control in place but not coded up
- File menu in place but not wired up
- This is avalon edit, it just works
- It's possible to send command and it displays the output !
- It's slow !