sparkup-y vim maps treetop grammar

# vim_maps.treetop - demo grammar for sparkup-y vim maps
# Barry Arthur, Sat May 28, 2011

# NOTE: The strange use of   ''   at the start of rules, like:
#
#  '' (some match elements here) { code block}
#
# was necessary to force the code block to be module-level
# and not syntax-node level. This seems to be a treetop
# peculiarity.

grammar VimMaps
  rule vimmap
    (string / keycode / keycombo)* {
      def value
        s = elements.map {|e| e.value}.join
        if $ctrl
          s += '>'
        end
        s
      end
    }
  end

  # handles both the double and single-char key combos.
  # The doubles are placed first so they can parse, otherwise
  # the single would greedily parse first and prevent the
  # double from being recognised.
  rule keycode
    '' (
         'bu' / 'en' / 'ex' / 'ho' / 'lx' / 'lt' /
         'pd' / 'pl' / 'pu' / 'sc' / 'sd' / 'si' /
         'sp' / 'tb' / 'un' / 'xx' /
         [ _,.behjklr]
       ) {
        def value
          keycodes = {
            ' '  => " ",
            '_'  => "",
            ','  => "",
            '.'  => "<Space>",
            'b'  => "<Bar>",
            'bu'  => " <buffer> ",
            'e'  => "<Esc>",
            'en' => "<End>",
            'ex' => " <expr> ",
            'h'  => "<Left>",
            'ho' => "<Home>",
            'j'  => "<Down>",
            'k'  => "<Up>",
            'l'  => "<Right>",
            'lx' => "<LocalLeader>",
            'lt' => "<lt>",
            'pd' => "<PageDown>",
            'pl' => "<Plug>",
            'pu' => "<PageUp>",
            'r'  => "<CR>",
            'sc' => " <script> ",
            'sd' => "<SID>",
            'si' => " <silent> ",
            'sp' => " <special> ",
            'tb' => "<Tab>",
            'un' => " <unique> ",
            'xx' => "<Leader>",
          }
          s = ''
          if $ctrl
            s = '>'
            $ctrl = nil
          end
          s + keycodes[text_value]
        end
      }
  end

  # handles the alt-, ctrl-, cmd-, meta-, and shift- key combos.
  # from: az,cx-n   generates: <a-z><c-x><c-n>
  # uses a global, $ctrl to signal that we're currently inside
  # a combo - when we process a non-combo, or multi-combo (using
  # the '-' char) we can close the preceding combo with '>'.
  rule keycombo
    '' combo:(ctrl:[-acdms] key:.) {
      def value
        s = ''
        if combo.ctrl.text_value == '-'
          '><' + $ctrl + '-' + combo.key.text_value
        else
          if $ctrl
            s = '>'
          end
          $ctrl = combo.ctrl.text_value
          s + '<' + $ctrl + '-' + combo.key.text_value
        end
      end
    }
  end

  # Handles any other text in the input and passes
  # it through as is (with double-quotes stripped).
  rule string
    '' ('"' ('\"' / !'"' .)* '"') {
      def value
        text_value[1..-2]
      end
    }
  end
end

#
#--8<--
#

#!/usr/bin/ruby

# vm.rb - demo parser harness for sparkup-y vim maps
# Barry Arthur, Sat May 28, 2011

require 'treetop'
Treetop.load File.expand_path("./vim_maps")

parser = VimMapsParser.new
puts parser.parse(ARGV.join).value