1 $ // This file is part of NIT ( http://www.nitlanguage.org ).
3 $ // Copyright 2008 Jean Privat <jean@pryen.org>
4 $ // Based on algorithms developped for ( http://www.sablecc.org/ ).
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
10 $ // http://www.apache.org/licenses/LICENSE-2.0
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.
18 $ template make_parser()
20 # State of the parser automata as stored in the parser stack.
22 # The internal state number
23 readable writable var _state: Int
25 # The node stored with the state in the stack
26 readable writable var _nodes: nullable Object
28 init(state: Int, nodes: nullable Object)
40 # Stack of pushed states and productions
41 var _stack: Array[State]
43 # Position in the stack
46 # Create a new parser based on a given lexer
50 _stack = new Array[State]
55 # Do a transition in the automata
56 private fun go_to(index: Int): Int
60 var high = parser_goto(index, 0) - 1
63 var middle = (low + high) / 2
64 var subindex = middle * 2 + 1 # +1 because parser_goto(index, 0) is the length
66 var goal = parser_goto(index, subindex)
69 else if state > goal then
72 return parser_goto(index, subindex+1)
76 return parser_goto(index, 2) # Default value
79 # Push someting in the state stack
80 private fun push(numstate: Int, list_node: nullable Object)
82 var pos = _stack_pos + 1
84 if pos < _stack.length then
85 var state = _stack[pos]
86 state.state = numstate
87 state.nodes = list_node
89 _stack.push(new State(numstate, list_node))
94 private fun state: Int
96 return _stack[_stack_pos].state
99 # Pop something from the stack state
100 private fun pop: nullable Object
102 var res = _stack[_stack_pos].nodes
103 _stack_pos = _stack_pos -1
107 # Build and return a full AST.
114 var token = lexer.peek
115 if token isa PError then
116 return new Start(null, token)
119 var state = self.state
120 var index = token.parser_index
121 var action_type = parser_action(state, 2)
122 var action_value = parser_action(state, 3)
125 var high = parser_action(state, 0) - 1
128 var middle = (low + high) / 2
129 var subindex = middle * 3 + 1 # +1 because parser_action(state, 0) is the length
131 var goal = parser_action(state, subindex)
134 else if index > goal then
137 action_type = parser_action(state, subindex+1)
138 action_value = parser_action(state, subindex+2)
143 if action_type == 0 then # SHIFT
144 push(action_value, lexer.next)
145 else if action_type == 1 then # REDUCE
146 _reduce_table[action_value].action(self)
147 else if action_type == 2 then # ACCEPT
148 var node2 = lexer.next
151 assert node1 isa ${/parser/prods/prod/@ename}
152 var node = new Start(node1, node2)
153 (new ComputeProdLocationVisitor).enter_visit(node)
155 else if action_type == 3 then # ERROR
156 var node2 = new PParserError.init_parser_error("Syntax error: unexpected {token}.", token.location, token)
157 var node = new Start(null, node2)
163 var _reduce_table: Array[ReduceAction]
164 private fun build_reduce_table
166 _reduce_table = new Array[ReduceAction].with_items(
167 $ foreach {rules/rule}
168 new ReduceAction@index(@leftside)[-sep ','-]
175 # Location on the first token after the start of a production
176 # So outside the production for epilon production
177 var _first_location: nullable Location
179 # Location of the last token before the end of a production
180 # So outside the production for epilon production
181 var _last_location: nullable Location
184 # Find location of production nodes
185 # Uses existing token locations to infer location of productions.
186 private class ComputeProdLocationVisitor
188 # Currenlty visited productions that need a first token
189 var _need_first_prods: Array[Prod] = new Array[Prod]
191 # Already visited epsilon productions that waits something after them
192 var _need_after_epsilons: Array[Prod] = new Array[Prod]
194 # Already visited epsilon production that waits something before them
195 var _need_before_epsilons: Array[Prod] = new Array[Prod]
197 # Location of the last visited token in the current production
198 var _last_location: nullable Location = null
200 redef fun visit(n: PNode)
206 # Add a first token to productions that need one
207 if not _need_first_prods.is_empty then
208 for no in _need_first_prods do
209 no._first_location = loc
211 _need_first_prods.clear
214 # Find location for already visited epsilon production that need one
215 if not _need_after_epsilons.is_empty then
216 for no in _need_after_epsilons do
217 # Epsilon production that is in the middle of a non-epsilon production
218 # The epsilon production has both a token before and after it
220 var startl = no._last_location
221 no.location = new Location(endl.file, startl.line_end, endl.line_start, startl.column_end, endl.column_start)
223 _need_after_epsilons.clear
227 _need_first_prods.add(n)
229 var old_last = _last_location
230 _last_location = null
232 var endl = _last_location
233 if endl == null then _last_location = old_last
235 n._last_location = endl
236 var startl = n._first_location
237 if startl != null then
238 # Non-epsilon production
241 n.location = new Location(startl.file, startl.line_start, endl.line_end, startl.column_start, endl.column_end)
243 if not _need_before_epsilons.is_empty then
244 var loc = new Location(startl.file, startl.line_start, startl.line_start, startl.column_start, startl.column_start)
245 for no in _need_before_epsilons do
246 # Epsilon production that starts the current non-epsilon production
249 _need_before_epsilons.clear
252 if not _need_after_epsilons.is_empty then
253 var loc = new Location(endl.file, endl.line_end, endl.line_end, endl.column_end, endl.column_end)
254 for no in _need_after_epsilons do
255 # Epsilon production that finishes the current non-epsilon production
258 _need_after_epsilons.clear
261 # No first token means epsilon production (or "throw all my tokens" production)
262 # So, it must be located it later
264 # Epsilon production that starts a parent non-epsilon production
265 _need_before_epsilons.add(n)
267 # Epsilon production in the middle or that finishes a parent non-epsilon production
268 _need_after_epsilons.add(n)
277 # Each reduca action has its own class, this one is the root of the hierarchy.
278 private abstract class ReduceAction
279 fun action(p: Parser) is abstract
280 fun concat(l1, l2 : Array[Object]): Array[Object]
282 if l1.is_empty then return l2
287 init(g: Int) do _goto = g
290 $ foreach {rules/rule}
291 private class ReduceAction@index
293 redef fun action(p: Parser)
295 var node_list: nullable Object = null
299 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = p.pop
301 $ when {@cmd='FETCHLIST'}
302 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@from,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
303 assert ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} isa Array[Object]
305 $ when {@cmd='FETCHNODE'}
306 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@from,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
307 assert ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} isa nullable @etype
309 $ when {@cmd='ADDNODE'}
310 if ${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} != null then
311 ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}.add(${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")})
314 $ when {@cmd='ADDLIST'}
315 ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = concat(${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}, ${translate(@fromlist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")})
317 $ when {@cmd='MAKELIST'}
318 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = new Array[Object]
320 $ when {@cmd='MAKENODE'}
322 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}: nullable @etype = new @etype.init_${translate(@etype,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}(
327 ${translate(.,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}[-sep ','-]
332 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}: nullable @etype = new @etype.init_${translate(@etype,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
335 $ when {@cmd='RETURNNODE'}
339 node_list = ${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
342 $ when {@cmd='RETURNLIST'}
343 node_list = ${translate(@list,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
347 p.push(p.go_to(_goto), node_list)
353 $ template make_parser_table()
354 $ foreach {parser_data/action_table/row}
355 static int parser_action_row${position()}[] = {
358 @from, @action, @to[-sep ','-]
363 const int* const parser_action_table[] = {
364 $ foreach {parser_data/action_table/row}
365 parser_action_row${position()}[-sep ','-]
369 $ foreach {parser_data/goto_table/row}
370 static int parser_goto_row${position()}[] = {
373 @from, @to[-sep ','-]
378 const int* const parser_goto_table[] = {
379 $ foreach {parser_data/goto_table/row}
380 parser_goto_row${position()}[-sep ','-]