src/parser/xss/parser.xss

   1 /* This file is part of NIT ( http://www.nitlanguage.org ).
   2  *
   3  * Copyright 2008 Jean Privat <jean@pryen.org>
   4  * Based on algorithms developped for ( http://www.sablecc.org/ ).
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18
  19 $ template make_parser()
  20
  21 # State of the parser automata as stored in the parser stack.
  22 private class State
  23         # The internal state number
  24         readable writable var _state: Int
  25
  26         # The node stored with the state in the stack
  27         readable writable var _nodes: nullable Object
  28
  29         init(state: Int, nodes: nullable Object)
  30         do
  31                 _state = state
  32                 _nodes = nodes
  33         end
  34 end
  35
  36 class Parser
  37 special ParserTable
  38         # Associated lexer
  39         var _lexer: Lexer
  40
  41         # Stack of pushed states and productions
  42         var _stack: Array[State]
  43
  44         # Position in the stack
  45         var _stack_pos: Int
  46
  47         # Create a new parser based on a given lexer
  48         init(lexer: Lexer)
  49         do
  50                 _lexer = lexer
  51                 _stack = new Array[State]
  52                 _stack_pos = -1
  53                 build_goto_table
  54                 build_action_table
  55                 build_reduce_table
  56         end
  57
  58         # Do a transition in the automata
  59         private fun go_to(index: Int): Int
  60         do
  61                 var state = state
  62                 var table = _goto_table[index]
  63                 var low = 1
  64                 var high = table.length/2 - 1
  65
  66                 while low <= high do
  67                         var middle = (low + high) / 2
  68                         var subindex = middle * 2
  69
  70                         if state < table[subindex] then
  71                                 high = middle - 1
  72                         else if state > table[subindex] then
  73                                 low = middle + 1
  74                         else
  75                                 return table[subindex + 1]
  76                         end
  77                 end
  78
  79                 return table[1] # Default value
  80         end
  81
  82         # Push someting in the state stack
  83         private fun push(numstate: Int, list_node: nullable Object)
  84         do
  85                 var pos = _stack_pos + 1
  86                 _stack_pos = pos
  87                 if pos < _stack.length then
  88                         var state = _stack[pos]
  89                         state.state = numstate
  90                         state.nodes = list_node
  91                 else
  92                         _stack.push(new State(numstate, list_node))
  93                 end
  94         end
  95
  96         # The current state
  97         private fun state: Int
  98         do
  99                 return _stack[_stack_pos].state
 100         end
 101
 102         # Pop something from the stack state
 103         private fun pop: nullable Object
 104         do
 105                 var res = _stack[_stack_pos].nodes
 106                 _stack_pos = _stack_pos -1
 107                 return res
 108         end
 109
 110         # Build and return a full AST.
 111         fun parse: Start
 112         do
 113                 push(0, null)
 114
 115                 var lexer = _lexer
 116                 while true do
 117                         var token = lexer.peek
 118                         var last_pos = token.pos
 119                         var last_line = token.line
 120
 121                         if token isa PError then
 122                                 return new Start(null, token)
 123                         end
 124
 125                         var index = token.parser_index
 126                         var table = _action_table[state]
 127                         var action_type = table[1]
 128                         var action_value = table[2]
 129
 130                         var low = 1
 131                         var high = table.length/3 - 1
 132
 133                         while low <= high do
 134                                 var middle = (low + high) / 2
 135                                 var subindex = middle * 3
 136
 137                                 if index < table[subindex] then
 138                                         high = middle - 1
 139                                 else if index > table[subindex] then
 140                                         low = middle + 1
 141                                 else
 142                                         action_type = table[subindex + 1]
 143                                         action_value = table[subindex + 2]
 144                                         high = low -1 # break
 145                                 end
 146                         end
 147
 148                         if action_type == 0 then # SHIFT
 149                                 push(action_value, lexer.next)
 150                         else if action_type == 1 then # REDUCE
 151                                 _reduce_table[action_value].action(self)
 152                         else if action_type == 2 then # ACCEPT
 153                                 var node2 = lexer.next
 154                                 assert node2 isa EOF
 155                                 var node1 = pop
 156                                 assert node1 isa ${/parser/prods/prod/@ename}
 157                                 var node = new Start(node1, node2)
 158                                 (new SearchTokensVisitor).visit(node)
 159                                 return node
 160                         else if action_type == 3 then # ERROR
 161                                 var node2 = new PError.init_error(lexer.filename, last_line, last_pos, error_messages[errors[action_value]])
 162                                 var node = new Start(null, node2)
 163                                 return node
 164                         end
 165                 end
 166                 abort
 167         end
 168
 169         var _reduce_table: Array[ReduceAction]
 170         private fun build_reduce_table
 171         do
 172                 _reduce_table = new Array[ReduceAction].with_items(
 173 $ foreach {rules/rule}
 174                         new ReduceAction@index[-sep ','-]
 175 $ end foreach
 176                 )
 177         end
 178 end
 179
 180 # Find first and last tokens of production nodes
 181 private class SearchTokensVisitor
 182 special Visitor
 183         var _untokenned_nodes: Array[Prod]
 184         var _last_token: nullable Token = null
 185         redef fun visit(n: nullable PNode)
 186         do
 187                 if n == null then
 188                         return
 189                 else if n isa Token then
 190                         _last_token = n
 191                         for no in _untokenned_nodes do
 192                                 no.first_token = n
 193                         end
 194                         _untokenned_nodes.clear
 195                 else
 196                         assert n isa Prod
 197                         _untokenned_nodes.add(n)
 198                         n.visit_all(self)
 199                         n.last_token = _last_token
 200                 end
 201         end
 202         init
 203         do
 204                 _untokenned_nodes = new Array[Prod]
 205         end
 206 end
 207
 208 # Each reduca action has its own class, this one is the root of the hierarchy.
 209 private abstract class ReduceAction
 210         fun action(p: Parser) is abstract
 211 end
 212
 213 $ foreach {rules/rule}
 214 private class ReduceAction@index
 215 special ReduceAction
 216         redef fun action(p: Parser)
 217         do
 218                                         var node_list: nullable Object = null
 219 $   foreach {action}
 220 $   choose
 221 $     when {@cmd='POP'}
 222                                         var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = p.pop
 223 $     end
 224 $     when {@cmd='FETCHLIST'}
 225                                         var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@from,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
 226                                         assert ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} isa Array[Object]
 227 $     end
 228 $     when {@cmd='FETCHNODE'}
 229                                         var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@from,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
 230                                         assert ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} isa nullable @etype
 231 $     end
 232 $     when {@cmd='ADDNODE'}
 233                                         if ${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} != null then
 234                                                 ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}.add(${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")})
 235                                         end
 236 $     end
 237 $     when {@cmd='ADDLIST'}
 238 #                                       if ${translate(@fromlist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} != null then
 239                                                 if ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}.is_empty then
 240                                                         ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@fromlist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
 241                                                 else
 242                                                         ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}.append(${translate(@fromlist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")})
 243                                                 end
 244 #                                       end
 245 $     end
 246 $     when {@cmd='MAKELIST'}
 247                                         var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = new Array[Object]
 248 $     end
 249 $     when {@cmd='MAKENODE'}
 250                                         var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}: nullable @etype = new @etype.init_${translate(@etype,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}(
 251 $       foreach {arg}
 252 $           if @null
 253                                                 null[-sep ','-]
 254 $           else
 255                                                 ${translate(.,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}[-sep ','-]
 256 $           end
 257 $       end foreach
 258                                         )
 259 $     end
 260 $     when {@cmd='RETURNNODE'}
 261 $       if @null
 262                                         node_list = null
 263 $       else
 264                                         node_list = ${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
 265 $       end
 266 $     end
 267 $     when {@cmd='RETURNLIST'}
 268                                         node_list = ${translate(@list,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
 269 $     end
 270 $   end choose
 271 $   end foreach
 272                                         p.push(p.go_to(@leftside), node_list)
 273         end
 274 init do end
 275 end
 276 $ end foreach
 277 $ end template
 278
 279 $ template make_parser_tables()
 280 # Parser that build a full AST
 281 abstract class ParserTable
 282         var _action_table: Array[Array[Int]]
 283         private fun build_action_table
 284         do
 285                 _action_table = once [
 286 $ foreach {parser_data/action_table/row}
 287                         action_table_row${position()}[-sep ','-]
 288 $ end foreach
 289                 ]
 290         end
 291
 292 $ foreach {parser_data/action_table/row}
 293         private fun action_table_row${position()}: Array[Int]
 294         do
 295                 return [
 296 $   foreach {action}
 297                                 @from, @action, @to [-sep ','-]
 298 $   end foreach
 299                         ]
 300         end
 301 $ end foreach
 302
 303         var _goto_table: Array[Array[Int]]
 304         private fun build_goto_table
 305         do
 306                 _goto_table = once [
 307 $ foreach {parser_data/goto_table/row}
 308                         [
 309 $   foreach {goto}
 310                                 @from, @to [-sep ','-]
 311 $   end foreach
 312                         ] [-sep ','-]
 313 $ end foreach
 314                 ]
 315         end
 316
 317         private fun error_messages: Array[String]
 318         do
 319                 return once [
 320 $ foreach {parser_data/error_messages/msg}
 321                         "${sablecc:string2escaped_unicode(.)}" [-sep ','-]
 322 $ end
 323                 ]
 324         end
 325
 326         private fun errors: Array[Int]
 327         do
 328                 return once [
 329                         [-foreach {parser_data/errors/i}-]${.} [-sep ','-] [-end-]
 330                 ]
 331         end
 332
 333         init do end
 334 end
 335 $ end template