Basic Usage

These instructions assume that you have already installed Juno. If you have not yet installed Juno, please see the Installation Instructions.

The Command Palette

To open the command panel, use Ctrl+Shift+p or go to Packages > Command Palette > Toggle. In the command palette, you can search for common commands. For example, type in "julia" and you will see the commands which relate to Julia (and the keyboard shortcuts for the commands).

Opening the Console Window

To open the console, use the command Ctrl+j then Ctrl+o, or go to Packages > Julia > Open Console. This will open a window with the title console. To use the console, simply type in a command and hit Enter. This will run the command in Julia (the first time a command is run, the connection between Julia and Atom will be installed, taking a bit more time). To clear the console, use the command Ctrl+j followed by Ctrl+c.

Using the console is similar to using the REPL. For example, to enter multi-line input, use Ctrl+Enter. Tab completion will be available with a window for selecting the desired completion (which can be scrolled through using the arrow keys). Juno also features enhanced displaying of output types. For example, types like Array show an arrow on the side. By clicking on the header for this output you will expand the array in the console. Note that floating point numbers truncate their displays as well: to see more digits, click on the number.

Inline Evaluation

You can evaluate your Julia code inline by navigating your cursor to the appropriate code and hitting Ctrl+Enter. This will run the code block that the cursor is contained in. For example, if you go to the top of a for loop, it will evaluate the whole for loop, or if it's inside of a function, it will evaluate the function (i.e. create the function). It's indentation based, so if you unindent the function body you can use Ctrl-Enter to run the lines of the function one by one, if you want. To specifically choose which code to evaluate, highlight the appropriate parts and use Ctrl+Enter. To evaluate the whole script, use Ctrl+Shift+Enter.

Cell Evaluation

Juno also supports cell-based evaluation. A cell boundary is defined by a line starting with ##, #---, or # %%. You can easily navigate cells via Alt-Up and Alt-Down, evaluate them with Alt-Enter, or evaluate a cell and move to the next one via Alt-Shift-Enter.

Activating the debugger

Activate the Juno debugger from the console like this:

Juno.@enter gcd(10, 20)

An editing pane will switch to the source for gcd and you will be able to step through it using a debug controller or key bindings (see below). Your console which switches to a debug> prompt, from which you can evaluate expressions that reference variables internal to gcd.

See Debugging for a step-by-step guide.

Common Keyboard Shortcuts

For MacOS, replace Ctrl by Cmd.

  • Ctrl+Shift+p - Open the command panel
  • Ctrl+Enter - Evaluate at the cursor
  • Ctrl+Shift+Enter - Evaluate the current file
  • Ctrl+j Ctrl+o - Open the console
  • Ctrl+j Ctrl+c - Clear the console
  • Ctrl+j Ctrl+s - Start Julia
  • Ctrl+j Ctrl+k - Kill the Julia process
  • Ctrl+j Ctrl+r - Open a REPL
  • Ctrl+j Ctrl+p - Open the Plot Pane
  • Ctrl+j Ctrl-d - Get the documentation for the symbol under the cursor
  • Ctrl+j Ctrl-g - Go to the definition of the symbol under the cursor

When debugging,

  • F10 - advance to next expression
  • F11 - step into function call
  • Shift-F11 - step out of function call

Adding Your Own Shortcuts

You can add custom commands and keybindings to julia, should you so wish. To create new commands, add something like the following to your

atom.packages.onDidActivatePackage (p) ->
  if is 'julia-client'
    juno = p.mainModule

    atom.commands.add '.item-views > atom-text-editor', 'julia-client:clear-console-and-run-file', ->


'.platform-win32 .item-views > atom-text-editor[data-grammar="source julia"]':
  'ctrl-shift-alt-enter': 'julia-client:clear-console-and-run-file'

to your keymap.cson (you can get to both files via Settings > Open Config Folder). It's also possible to add new keybindings for existing commands, such as f5 for julia-client:run-file.

Note that you will need to muck around with julia-client's internals for defining custom commands, so your code might break on new releases. You'll also need to figure out which functions you can use for what – julia-client's commands will probably be helpful for that.

Using the Plot Pane

Use of the plot pane will be automatic by plotting packages which support the interface. The following describes the package interactions in more depth.

The Plots.jl Ecosystem

Plots.jl supports usage of the plot pane with compatible backends. The backends which are compatible are:

The plot command will plot to the plot pane by default. To open up a non-plot pane window, use the gui() command. For example,

using Plots
pyplot() # Choose a backend
plot(rand(4,4)) # This will plot to the plot pane
gui() # This will open up a separate interactive GUI window

Other plotting packages

These packages are compatible with Juno and will also use the plot plane:

Using the Workspace Pane

A workspace pane is available for showing the variables declared in the workspace. To open the pane, go to Packages > Julia > Open Workspace.