78 lines
2.0 KiB
Ruby
78 lines
2.0 KiB
Ruby
require "execjs"
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require "nokogiri"
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require "net/http"
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require "json"
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require "cgi"
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require "optparse"
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class KatexRenderer
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def initialize(source)
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@context = ExecJS.compile(source)
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@inline_cache = {}
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@display_cache = {}
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end
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def render(display, string)
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cache = display ? @display_cache : @inline_cache
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comment = display ? "display" : string
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string = CGI.unescapeHTML string
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cache.fetch(string) do
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puts " Rendering #{comment}"
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options = { "throwOnError" => false, "displayMode" => display }
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cache[string] = @context.call("katex.renderToString", string, options)
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end
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end
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def substitute(content)
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found_any = false
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rendered = content.gsub /\\\(((?:[^\\]|\\[^\)])*)\\\)/ do |match|
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found_any = true
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render(false, $~[1])
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end
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rendered = rendered.gsub /\$\$((?:[^\$]|$[^\$])*)\$\$/ do |match|
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found_any = true
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render(true, $~[1])
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end
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return rendered, found_any
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end
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end
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# Provided via this project's Gemfile
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ExecJS.runtime = ExecJS::Runtimes::Duktape
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katex = nil
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OptionParser.new do |opts|
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opts.banner = "Usage: convert.rb [options]"
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opts.on("--katex-js-file=FILE", "Use the given KaTeX JS file to process LaTeX") do |f|
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katex = f
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end
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end.parse!
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files = ARGV
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if katex
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katex = File.read(katex)
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else
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katex = Net::HTTP.get(URI("https://static.danilafe.com/katex/katex.min.js"))
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end
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renderer = KatexRenderer.new(katex)
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files.each do |file|
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puts "Rendering file: #{file}"
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document = Nokogiri::HTML.parse(File.open(file))
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found_any = false
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document.search('//*[not(ancestor-or-self::code or ancestor-or-self::script)]/text()').each do |t|
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rendered, found_any_in_text = renderer.substitute(t.content)
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found_any ||= found_any_in_text
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t.replace(rendered)
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end
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# If we didn't find any mathematical equations, no need to include KaTeX CSS.
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unless found_any
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document.css('link[href$="katex.css"], link[href$="katex.min.css"]').each(&:remove)
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end
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File.write(file, document.to_html(encoding: 'UTF-8'))
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end
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