Class: Jekyll::Pseudo::Grammar

Inherits:
Object
  • Object
show all
Defined in:
lib/jekyll-pseudo/grammar.rb

Instance Method Summary collapse

Instance Method Details

#format(txt, brush) ⇒ Object

format a block of text, giving html as output



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# File 'lib/jekyll-pseudo/grammar.rb', line 5

def format(txt, brush)
  results = []

  mappings = [
    [/\#(.*$)/, :comment],
    [/\b([A-Z]\w+)/, :sym],
    [/(\w+)(?=[({\[])/, :fn],
    [/(\".*?\")/, :string],
    [/(<-|->|\+\+|<=|>=|--)/, :op], # try these operations first
    [/([-()\[\]{}=<>+])/, :op],     # and these second
    [/^(\s)+/, :indent]
  ]
  
  txt.strip!

  # lazy man's parser (we don't do that backtracking business)
  cursor = 0
  while true
    matches = mappings.map do |pair|
      [pair[0].match(txt, cursor), pair[1]]
    end

    upto = matches.min_by do |pair|
      matchdata = pair[0]
      if matchdata == nil
        txt.size
      else
        matchdata.begin(0)
      end
    end

    if upto[0] != nil
      results << brush.plain(txt.slice(cursor, upto[0].begin(0)-cursor))

      match = upto[0][1]
      # which match?
      results << brush.method(upto[1]).call(match)
      cursor = upto[0].end(1)
    else
      # no matches remaining
      results << brush.plain(txt.slice(cursor, txt.size))
      break
    end
  end

  # puts "FINAL: #{results.inspect}"
  # puts "     = #{results.join('').inspect}"
  return results.join('')
end