_plugins/singledollar.rb


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# https://gist.github.com/sp301415/db9f7bee03bda483aa2ca7c0ca92fbfa

require 'kramdown/parser/kramdown'
require 'kramdown-parser-gfm'

class Kramdown::Parser::GFMKatex < Kramdown::Parser::GFM
    # Override inline math parser
    @@parsers.delete(:inline_math)

    INLINE_MATH_START = /(\$+)([^\$]+)(\$+)/m

    def parse_inline_math
        start_line_number = @src.current_line_number
        @src.pos += @src.matched_size
        @tree.children << Element.new(:math, @src.matched[1..-2], nil, category: :span, location: start_line_number)
    end

    define_parser(:inline_math, INLINE_MATH_START, '\$')
end