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Julia Syntax Highlighting

The JuliaSyntaxHighlighting library serves as a small convenience package to syntax highlight Julia code using JuliaSyntax and StyledStrings.

It is intended for use across the standard library, and the wider ecosystem.

Functions

JuliaSyntaxHighlighting.highlight — Function
highlight(content::Union{AbstractString, IO},
          ast::JuliaSyntax.GreenNode = <parsed content>;
          syntax_errors::Bool = false) -> AnnotatedString{String}

Apply syntax highlighting to content using JuliaSyntax.

By default, JuliaSyntax.parseall is used to generate to ast with the ignore_errors keyword argument set to true. Alternatively, one may provide a pre-generated ast.

When syntax_errors is set, the julia_error face is applied to detected syntax errors.

Warning

Note that the particular faces used by JuliaSyntax, and the way they are applied, is subject to change.

Examples

julia> JuliaSyntaxHighlighting.highlight("sum(1:8)")
"sum(1:8)"

julia> JuliaSyntaxHighlighting.highlight("sum(1:8)") |> Base.annotations
6-element Vector{@NamedTuple{region::UnitRange{Int64}, label::Symbol, value}}:
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((1:3, :face, :julia_funcall))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((4:4, :face, :julia_rainbow_paren_1))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((5:5, :face, :julia_number))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((6:6, :face, :julia_operator))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((7:7, :face, :julia_number))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((8:8, :face, :julia_rainbow_paren_1))
JuliaSyntaxHighlighting.highlight! — Function
highlight!(content::Union{AnnotatedString, SubString{AnnotatedString}},
           ast::JuliaSyntax.GreenNode = <parsed content>;
           syntax_errors::Bool = false) -> content

Modify content by applying syntax highlighting using JuliaSyntax.

By default, JuliaSyntax.parseall is used to generate to ast with the ignore_errors keyword argument set to true. Alternatively, one may provide a pre-generated ast.

When syntax_errors is set, the julia_error face is applied to detected syntax errors.

Warning

Note that the particular faces used by JuliaSyntax, and the way they are applied, is subject to change.

Examples

julia> str = Base.AnnotatedString("sum(1:8)")
"sum(1:8)"

julia> JuliaSyntaxHighlighting.highlight!(str)
"sum(1:8)"

julia> Base.annotations(str)
6-element Vector{@NamedTuple{region::UnitRange{Int64}, label::Symbol, value}}:
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((1:3, :face, :julia_funcall))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((4:4, :face, :julia_rainbow_paren_1))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((5:5, :face, :julia_number))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((6:6, :face, :julia_operator))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((7:7, :face, :julia_number))
 @NamedTuple{region::UnitRange{Int64}, label::Symbol, value}((8:8, :face, :julia_rainbow_paren_1))

Faces

The highlight/highlight! methods work by applying custom faces to Julia code. As part of the standard library, these faces use privileged face names, of the form julia_*. These can be re-used in other packages, and customised with faces.toml configuration.

Unstable faces

The particular faces used by JuliaSyntaxHighlighting are liable to change without warning in point releases. As the syntax highlighting rules are refined over time, changes should become less and less frequent though.

The current set of faces, and their default values are as follows:

  • julia_macro: magenta
  • julia_symbol: magenta
  • julia_singleton_identifier: inherits from julia_symbol
  • julia_type: yellow
  • julia_typedec: bright blue
  • julia_comment: grey
  • julia_string: green
  • julia_regex: inherits from julia_string
  • julia_backslash_literal: magenta, inherits from julia_string
  • julia_string_delim: bright green
  • julia_cmdstring: inherits from julia_string
  • julia_char: inherits from julia_string
  • julia_char_delim: inherits from julia_string_delim
  • julia_number: bright magenta
  • julia_bool: inherits from julia_number
  • julia_funcall: cyan
  • julia_broadcast: bright blue, bold
  • julia_builtin: bright blue
  • julia_operator: blue
  • julia_comparator: inherits from julia_operator
  • julia_assignment: bright red
  • julia_keyword: red
  • julia_parentheses: unstyled
  • julia_unpaired_parentheses: inherit from julia_error and julia_parentheses
  • julia_error: red background
  • julia_rainbow_paren_1: bright green, inherits from julia_parentheses
  • julia_rainbow_paren_2: bright blue, inherits from julia_parentheses
  • julia_rainbow_paren_3: bright red, inherits from julia_parentheses
  • julia_rainbow_paren_4: inherits from julia_rainbow_paren_1
  • julia_rainbow_paren_5: inherits from julia_rainbow_paren_2
  • julia_rainbow_paren_6: inherits from julia_rainbow_paren_3
  • julia_rainbow_bracket_1: blue, inherits from julia_parentheses
  • julia_rainbow_bracket_2: brightmagenta, inherits from `juliaparentheses`
  • julia_rainbow_bracket_3: inherits from julia_rainbow_bracket_1
  • julia_rainbow_bracket_4: inherits from julia_rainbow_bracket_2
  • julia_rainbow_bracket_5: inherits from julia_rainbow_bracket_1
  • julia_rainbow_bracket_6: inherits from julia_rainbow_bracket_2
  • julia_rainbow_curly_1: bright yellow, inherits from julia_parentheses
  • julia_rainbow_curly_2: yellow, inherits from julia_parentheses
  • julia_rainbow_curly_3: inherits from julia_rainbow_curly_1
  • julia_rainbow_curly_4: inherits from julia_rainbow_curly_2
  • julia_rainbow_curly_5: inherits from julia_rainbow_curly_1
  • julia_rainbow_curly_6: inherits from julia_rainbow_curly_2