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@zpao
Created May 10, 2013 20:19
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Highlight specific lines of code with Markdown + Jekyll + Redcarpet
# Replace Jekyll's handling of the Redcarpet code_block (which already adds
# support for highlighting, but needs support for the very non-standard
# "code fences with line highlights" extension).
# Since this is currently depending on Redcarpet to cooperate, we are going to
# be naive, and only allow line highlighting when a language is specified. If
# you don't want any syntax highlighting but want to highlight lines, then you
# need to specify text as your language (or it will break), like:
# ```text{4}
module Jekyll
module Converters
class Markdown
class RedcarpetParser
module WithPygments
def block_code(code, lang)
require 'pygments'
lang_parts = lang && lang.split('{')
lang = lang_parts && !lang_parts[0].empty? && lang_parts[0] || 'text'
hl_lines = ''
if lang_parts && lang_parts.size >= 2
hl_lines = lang_parts[1].gsub(/[{}]/, '').split(',').map do |ln|
if matches = /(\d+)-(\d+)/.match(ln)
ln = Range.new(matches[1], matches[2]).to_a.join(' ')
end
ln
end.join(' ')
end
output = add_code_tags(
Pygments.highlight(code, :lexer => lang,
:options => { :encoding => 'utf-8', :hl_lines => hl_lines }),
lang
)
end
end
end
end
end
end
@cyrusdavid
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Hi, how to use this?

@msaffitz
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msaffitz commented Jan 9, 2014

For other's, here's the original blog post: http://zpao.com/posts/adding-line-highlights-to-markdown-code-fences/

@kinoute
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kinoute commented Mar 29, 2021

Any chance to adapt this to Jekyll 4+ that uses Rouge now instead of Pygments?

Rouge recently added this feature but Jekyll still doesn't make use of it.

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