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

   1 require 'escape_helper'
   2
   3 module Ohcount
   4         # A Monoglot is a compile-time code generator.
   5         # It generates C source code which defines the states and transitions
   6         # required for a single language parser.
   7         #
   8         # To create a parser which spans multiple languages, use a Polyglot.
   9         class Monoglot
  10                 include EscapeHelper
  11
  12                 # The name must be unique
  13                 attr_reader :name
  14
  15                 # A collection of State objects representing possible states
  16                 attr_reader :states
  17
  18                 # The Transition objects defining transitions between states
  19                 attr_reader :transitions
  20
  21                 def initialize(name, states = [], transitions = [])
  22                         @name = name
  23                         @states = states
  24                         @transitions = transitions
  25                 end
  26
  27                 # Emit the generated C code for the state machine definition.
  28                 def print(io)
  29                         Monoglot::print_banner(io, name)
  30                         print_states(io)
  31                         print_transitions(io)
  32                         print_polyglot_def(io)
  33                 end
  34
  35                 def self.print_banner(io, name)
  36                         io.puts ""
  37                         io.puts "/*****************************************************************************"
  38                         left = (80 - name.size)/2
  39                         io.write " "*left
  40                         io.puts name
  41                         io.puts "*****************************************************************************/"
  42                 end
  43
  44                 def definition
  45                 "#{ @name.upcase }_POLYGLOT"
  46                 end
  47                 protected
  48
  49                 def print_states(io)
  50                         #define each
  51                         io.puts "/* States */"
  52                         @states.each do |s|
  53                                 s.print(io)
  54                         end
  55
  56                         # now define the collection
  57                         io.write "State *#{ name.upcase }_STATES[] = { "
  58                         @states.each do |s|
  59                                 io.write "&#{ s.definition }, "
  60                         end
  61                         io.write "NULL };\n"
  62                 end
  63
  64                 def print_transitions(io)
  65                         io.puts "/* Transitions */"
  66                         # print each transition
  67                         @transitions.each do |t|
  68                                 t.print(io)
  69                         end
  70
  71                         #aggregate the transitions
  72                         io.write  "Transition *#{ name.upcase }_TRANSITIONS[] = {"
  73                         @transitions.each do |t|
  74                                 io.write " &#{ t.definition },"
  75                         end
  76                         io.write " NULL};\n"
  77                 end
  78
  79                 def print_polyglot_def(io)
  80                         io.puts <<LANG_DEF
  81 Polyglot #{ definition } = {
  82         "#{ @name.downcase }",
  83                         #{ @name.upcase }_STATES,
  84                         #{ @name.upcase }_TRANSITIONS,
  85         NULL
  86 };
  87 LANG_DEF
  88                 end
  89
  90         end
  91 end