Workflow Tips

Here are some tips for working with Julia efficiently.

REPL-based workflow

As already elaborated in Interacting With Julia, Julia’s REPL provides rich functionality that facilitates an efficient interactive workflow. Here are some tips that might further enhance your experience at the command line.

A basic editor/REPL workflow

The most basic Julia workflows involve using a text editor in conjunction with the julia command line. A common pattern includes the following elements:

  • Put code under development in a temporary module. Create a file, say Tmp.jl, and include within it

    module Tmp
    
    <your definitions here>
    
    end
    
  • Put your test code in another file. Create another file, say tst.jl, which begins with

    import Tmp
    

    and includes tests for the contents of Tmp. The value of using import versus using is that you can call reload ("Tmp") instead of having to restart the REPL when your definintions change. Of course, the cost is the need to prepend Tmp. to uses of names defined in your module. (You can lower that cost by keeping your module name short.)

    Alternatively, you can wrap the contents of your test file in a module, as

    module Tst
        using Tmp
    
        <scratch work>
    
    end
    

    The advantage is that you can now do using Tmp in your test code and can therefore avoid prepending Tmp. everywhere. The disadvantage is that code can no longer be selectively copied to the REPL without some tweaking.

  • Lather. Rinse. Repeat. Explore ideas at the julia command prompt. Save good ideas in tst.jl. Occasionally restart the REPL, issuing

    reload("Tmp")
    include("tst.jl")
    

Simplify initialization

To simplify restarting the REPL, put project-specific initialization code in a file, say _init.jl, which you can run on startup by issuing the command:

julia -L _init.jl

If you further add the following to your .juliarc.jl file

isfile("_init.jl") && require("_init.jl")

then calling julia from that directory will run the initialization code without the additional command line argument.

Browser-based workflow

It is also possible to interact with a Julia REPL in the browser via IJulia. See the package home for details.