Backport racc-1.4.15 from upstream.

1 files changed, 316 insertions, 0 deletions

diff --git a/lib/racc/statetransitiontable.rb b/lib/racc/statetransitiontable.rb
new file mode 100644
index 0000000000..23df4102ec
--- /dev/null
+++ b/lib/racc/statetransitiontable.rb
@@ -0,0 +1,316 @@
+#
+# $Id: 4c5f4311663b6d03050953d64d6a0e7905ff2216 $
+#
+# Copyright (c) 1999-2006 Minero Aoki
+#
+# This program is free software.
+# You can distribute/modify this program under the terms of
+# the GNU LGPL, Lesser General Public License version 2.1.
+# For details of LGPL, see the file "COPYING".
+#
+
+require 'racc/parser'
+
+unless Object.method_defined?(:funcall)
+  class Object
+    alias funcall __send__
+  end
+end
+
+module Racc
+
+  StateTransitionTable = Struct.new(:action_table,
+                                    :action_check,
+                                    :action_default,
+                                    :action_pointer,
+                                    :goto_table,
+                                    :goto_check,
+                                    :goto_default,
+                                    :goto_pointer,
+                                    :token_table,
+                                    :reduce_table,
+                                    :reduce_n,
+                                    :shift_n,
+                                    :nt_base,
+                                    :token_to_s_table,
+                                    :use_result_var,
+                                    :debug_parser)
+  class StateTransitionTable   # reopen
+    def StateTransitionTable.generate(states)
+      StateTransitionTableGenerator.new(states).generate
+    end
+
+    def initialize(states)
+      super()
+      @states = states
+      @grammar = states.grammar
+      self.use_result_var = true
+      self.debug_parser = true
+    end
+
+    attr_reader :states
+    attr_reader :grammar
+
+    def parser_class
+      ParserClassGenerator.new(@states).generate
+    end
+
+    def token_value_table
+      h = {}
+      token_table().each do |sym, i|
+        h[sym.value] = i
+      end
+      h
+    end
+  end
+
+
+  class StateTransitionTableGenerator
+
+    def initialize(states)
+      @states = states
+      @grammar = states.grammar
+    end
+
+    def generate
+      t = StateTransitionTable.new(@states)
+      gen_action_tables t, @states
+      gen_goto_tables t, @grammar
+      t.token_table = token_table(@grammar)
+      t.reduce_table = reduce_table(@grammar)
+      t.reduce_n = @states.reduce_n
+      t.shift_n = @states.shift_n
+      t.nt_base = @grammar.nonterminal_base
+      t.token_to_s_table = @grammar.symbols.map {|sym| sym.to_s }
+      t
+    end
+
+    def reduce_table(grammar)
+      t = [0, 0, :racc_error]
+      grammar.each_with_index do |rule, idx|
+        next if idx == 0
+        t.push rule.size
+        t.push rule.target.ident
+        t.push(if rule.action.empty?   # and @params.omit_action_call?
+               then :_reduce_none
+               else "_reduce_#{idx}".intern
+               end)
+      end
+      t
+    end
+
+    def token_table(grammar)
+      h = {}
+      grammar.symboltable.terminals.each do |t|
+        h[t] = t.ident
+      end
+      h
+    end
+
+    def gen_action_tables(t, states)
+      t.action_table = yytable  = []
+      t.action_check = yycheck  = []
+      t.action_default = yydefact = []
+      t.action_pointer = yypact   = []
+      e1 = []
+      e2 = []
+      states.each do |state|
+        yydefact.push act2actid(state.defact)
+        if state.action.empty?
+          yypact.push nil
+          next
+        end
+        vector = []
+        state.action.each do |tok, act|
+          vector[tok.ident] = act2actid(act)
+        end
+        addent e1, vector, state.ident, yypact
+      end
+      set_table e1, e2, yytable, yycheck, yypact
+    end
+
+    def gen_goto_tables(t, grammar)
+      t.goto_table   = yytable2  = []
+      t.goto_check   = yycheck2  = []
+      t.goto_pointer = yypgoto   = []
+      t.goto_default = yydefgoto = []
+      e1 = []
+      e2 = []
+      grammar.each_nonterminal do |tok|
+        tmp = []
+
+        # decide default
+        freq = Array.new(@states.size, 0)
+        @states.each do |state|
+          st = state.goto_table[tok]
+          if st
+            st = st.ident
+            freq[st] += 1
+          end
+          tmp[state.ident] = st
+        end
+        max = freq.max
+        if max > 1
+          default = freq.index(max)
+          tmp.map! {|i| default == i ? nil : i }
+        else
+          default = nil
+        end
+        yydefgoto.push default
+
+        # delete default value
+        tmp.pop until tmp.last or tmp.empty?
+        if tmp.compact.empty?
+          # only default
+          yypgoto.push nil
+          next
+        end
+
+        addent e1, tmp, (tok.ident - grammar.nonterminal_base), yypgoto
+      end
+      set_table e1, e2, yytable2, yycheck2, yypgoto
+    end
+
+    def addent(all, arr, chkval, ptr)
+      max = arr.size
+      min = nil
+      arr.each_with_index do |item, idx|
+        if item
+          min ||= idx
+        end
+      end
+      ptr.push(-7777)    # mark
+      arr = arr[min...max]
+      all.push [arr, chkval, mkmapexp(arr), min, ptr.size - 1]
+    end
+
+    n = 2 ** 16
+    begin
+      Regexp.compile("a{#{n}}")
+      RE_DUP_MAX = n
+    rescue RegexpError
+      n /= 2
+      retry
+    end
+
+    def mkmapexp(arr)
+      i = ii = 0
+      as = arr.size
+      map = ''
+      maxdup = RE_DUP_MAX
+      curr = nil
+      while i < as
+        ii = i + 1
+        if arr[i]
+          ii += 1 while ii < as and arr[ii]
+          curr = '-'
+        else
+          ii += 1 while ii < as and not arr[ii]
+          curr = '.'
+        end
+
+        offset = ii - i
+        if offset == 1
+          map << curr
+        else
+          while offset > maxdup
+            map << "#{curr}{#{maxdup}}"
+            offset -= maxdup
+          end
+          map << "#{curr}{#{offset}}" if offset > 1
+        end
+        i = ii
+      end
+      Regexp.compile(map, 'n')
+    end
+
+    def set_table(entries, dummy, tbl, chk, ptr)
+      upper = 0
+      map = '-' * 10240
+
+      # sort long to short
+      entries.sort! {|a,b| b[0].size <=> a[0].size }
+
+      entries.each do |arr, chkval, expr, min, ptri|
+        if upper + arr.size > map.size
+          map << '-' * (arr.size + 1024)
+        end
+        idx = map.index(expr)
+        ptr[ptri] = idx - min
+        arr.each_with_index do |item, i|
+          if item
+            i += idx
+            tbl[i] = item
+            chk[i] = chkval
+            map[i] = ?o
+          end
+        end
+        upper = idx + arr.size
+      end
+    end
+
+    def act2actid(act)
+      case act
+      when Shift  then act.goto_id
+      when Reduce then -act.ruleid
+      when Accept then @states.shift_n
+      when Error  then @states.reduce_n * -1
+      else
+        raise "racc: fatal: wrong act type #{act.class} in action table"
+      end
+    end
+
+  end
+
+
+  class ParserClassGenerator
+
+    def initialize(states)
+      @states = states
+      @grammar = states.grammar
+    end
+
+    def generate
+      table = @states.state_transition_table
+      c = Class.new(::Racc::Parser)
+      c.const_set :Racc_arg, [table.action_table,
+                              table.action_check,
+                              table.action_default,
+                              table.action_pointer,
+                              table.goto_table,
+                              table.goto_check,
+                              table.goto_default,
+                              table.goto_pointer,
+                              table.nt_base,
+                              table.reduce_table,
+                              table.token_value_table,
+                              table.shift_n,
+                              table.reduce_n,
+                              false]
+      c.const_set :Racc_token_to_s_table, table.token_to_s_table
+      c.const_set :Racc_debug_parser, true
+      define_actions c
+      c
+    end
+
+    private
+
+    def define_actions(c)
+      c.module_eval "def _reduce_none(vals, vstack) vals[0] end"
+      @grammar.each do |rule|
+        if rule.action.empty?
+          c.funcall(:alias_method, "_reduce_#{rule.ident}", :_reduce_none)
+        else
+          c.funcall(:define_method, "_racc_action_#{rule.ident}", &rule.action.proc)
+          c.module_eval(<<-End, __FILE__, __LINE__ + 1)
+            def _reduce_#{rule.ident}(vals, vstack)
+              _racc_action_#{rule.ident}(*vals)
+            end
+          End
+        end
+      end
+    end
+
+  end
+
+end   # module Racc