git.oblomov.eu Git - ohcount/blob - ext/ohcount_native/glots/polyglot.rb

   1 require 'monoglot'
   2
   3 module Ohcount
   4         # A Polyglot is a compile-time code generator.
   5         # It generates C code which defines the states and transitions
   6         # required for a complex parser which can span multiple languages.
   7         #
   8         # For instance, an HTML parser might understand Javascript, CSS, and
   9         # basic HTML. All of these languages would be defined in Monoglots,
  10         # then the overall HTML parser would be defined as a Polyglot
  11         # spanning several Monoglots.
  12         class Polyglot < Monoglot
  13                 # Transitions above and beyond those defined in the child Monoglots.
  14                 # These are transitions which move us from a state in one Monoglot to
  15                 # a state in another Monoglot.
  16                 attr_reader :extra_transitions
  17
  18                 # The Polyglot may require additional states beyond those defined in the
  19                 # child Monoglots. Those extra states are defined here.
  20                 attr_reader :extra_states
  21
  22                 def print_states(io)
  23                         #define each
  24                         io.puts "/* States */"
  25                         @extra_states.each do |s|
  26                                 s.print(io)
  27                         end
  28
  29                         # now define the collection
  30                         io.write "State *#{ name.upcase }_STATES[] = { "
  31                         all_states.each do |s|
  32                                 io.write "&#{ s.definition }, "
  33                         end
  34                         io.write "NULL };\n"
  35                 end
  36
  37                 def all_states
  38                         @extra_states + @states
  39                 end
  40
  41                 def all_transitions
  42                         @extra_transitions + @transitions
  43                 end
  44
  45                 def print_transitions(io)
  46                         io.puts "/* Transitions */"
  47                         # print each transition
  48                         @extra_transitions.each do |t|
  49                                 t.print(io)
  50                         end
  51
  52                         #aggregate the transitions
  53                         io.write  "Transition *#{ name.upcase }_TRANSITIONS[] = {"
  54                         all_transitions.each do |t|
  55                                 io.write " &#{ t.definition },"
  56                         end
  57                         io.write " NULL};\n"
  58                 end
  59         end
  60 end