Syntax highlighting

The Syntax highlighting pass transforms input text in the REPL to highlighted text, highlighting keyword, operators, symbols, strings etc. in different colors. There are a few color schemes that comes with OhMyREPL but it is fairly easy to create your own to your liking.

Default schemes

The current default colorschemes that comes with OhMyREPL are

• "JuliaDefault" - the default Julia scheme, white and bold.
• "Monokai16" - 16 color Monokai
• "Monokai256" - 256 colors Monokai
• "Monokai24bit" - 24 bit colored Monokai
• "BoxyMonokai256" - 256 colors Monokai from here
• "TomorrowNightBright" - 256 colors Tomorrow Night Bright
• "TomorrowNightBright24bit" - 24 bit colored Tomorrow Night Bright
• "OneDark" - 24 bit colored OneDark
• "Base16MaterialDarker" - 24-bit Base16 Material Darker color scheme by Nate Peters
• "GruvboxDark" - Dark-mode variation of the Gruvbox color scheme by Pavel Pertsev.
• "GitHubLight", "GitHubDark" and "GitHubDarkDimmed" - GitHub's colorschemes, matching the VS Code themes

By default, "Monokai16" will be used on Windows and "Monokai256" otherwise. To test the supported colors in your terminal you can use Crayons.test_system_colors(), Crayons.test_256_colors(), Crayons.test_24bit_colors() to test 16, 256 and 24 bit colors respectively.

Preview

To see an example output of a colorscheme use test_colorscheme(name::String, [test_string::String]). If a test_string is not given, a default string will be used.

Activate

To activate a colorscheme use colorscheme!(name::String)

Creating your own colorschemes.

This section will describe how to create your own colorscheme.

We start by loading the Crayons package and importing the SyntaxHighlighter module.

using Crayons
import OhMyREPL: Passes.SyntaxHighlighter

We now create a default colorscheme:

scheme = SyntaxHighlighter.ColorScheme()

By using the function test_colorscheme we can see that the default colorscheme simply prints everything in the default color:

There are a number of setter function that updates the colorscheme. They are called like setter!(cs::ColorScheme, crayon::Crayon). The different setters are:

• symbol! - A symbol, ex :symbol
• comment! - A comment, ex # comment, #= block comment =#
• string! - A string or char, ex """string""", 'a'
• call! - A functionc all, ex foo()
• op! - An operator, ex *, √
• keyword! - A keyword, ex function, begin, try
• function_def! - A function definition, ex function foo(x) x end
• error! - An error in the Tokenizer, ex #= unending multi comment
• argdef! - Definition of a type, ex ::Float64
• macro! - A macro, ex @time
• number! - A number, ex 100, 100_00.0, 0xf00
• text! - Nothing of the above

Let us set the strings to be printed in yellow, numbers to be printed in bold, and function calls to be printed in cyan:

SyntaxHighlighter.string!(scheme, Crayon(foreground = :yellow))
SyntaxHighlighter.number!(scheme, Crayon(bold = true))
SyntaxHighlighter.call!(scheme, Crayon(foreground = :cyan))

By recalling test_colorscheme on the scheme we can see it has been updated:

By continuing in this fashion you can build up a full colorscheme. When you are satisfied with your colorscheme you can add it to the group of color schemes and activate it as:

You can look in the source code to see how the default color schemes are made.

For fun, the code below creates a truly random colorscheme:

function rand_token()
    Crayon(background = rand(Bool) ? :nothing : rand(1:256),
              foreground = rand(Bool) ? :nothing : rand(1:256),
              bold = rand(Bool), italics = rand(Bool), underline = rand(Bool))
end

function create_random_colorscheme()
    random = SyntaxHighlighter.ColorScheme()
    SyntaxHighlighter.symbol!(random,rand_token())
    SyntaxHighlighter.comment!(random, rand_token())
    SyntaxHighlighter.string!(random, rand_token())
    SyntaxHighlighter.call!(random, rand_token())
    SyntaxHighlighter.op!(random, rand_token())
    SyntaxHighlighter.keyword!(random, rand_token())
    SyntaxHighlighter.macro!(random, rand_token())
    SyntaxHighlighter.function_def!(random, rand_token())
    SyntaxHighlighter.text!(random, rand_token())
    SyntaxHighlighter.error!(random, rand_token())
    SyntaxHighlighter.argdef!(random, rand_token())
    SyntaxHighlighter.number!(random, rand_token())
    return random
end

test_colorscheme(create_random_colorscheme())