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.
19 $ template make_parser()
21 # State of the parser automata as stored in the parser stack.
23 # The internal state number
24 readable writable attr _state: Int
26 # The node stored with the state in the stack
27 readable writable attr _nodes: Object
29 init(state: Int, nodes: Object)
40 # Stack of pushed states and productions
41 attr _stack: Array[State]
43 # Position in the stack
46 # Create a new parser based on a given lexer
50 _stack = new Array[State]
57 # Do a transition in the automata
58 private meth go_to(index: Int): Int
61 var table = _goto_table[index]
63 var high = table.length/2 - 1
66 var middle = (low + high) / 2
67 var subindex = middle * 2
69 if state < table[subindex] then
71 else if state > table[subindex] then
74 return table[subindex + 1]
78 return table[1] # Default value
81 # Push someting in the state stack
82 private meth push(numstate: Int, list_node: Object)
84 var pos = _stack_pos + 1
86 if pos < _stack.length then
87 var state = _stack[pos]
88 state.state = numstate
89 state.nodes = list_node
91 _stack.push(new State(numstate, list_node))
96 private meth state: Int
98 return _stack[_stack_pos].state
101 # Pop something from the stack state
102 private meth pop: Object
104 var res = _stack[_stack_pos].nodes
105 _stack_pos = _stack_pos -1
109 # Build and return a full AST.
114 var ign: List[Token] = null
117 var token = lexer.peek
118 var last_pos = token.pos
119 var last_line = token.line
121 if token isa PError then
122 assert token isa PError
123 return new Start(null, token)
126 var index = token.parser_index
127 var table = _action_table[state]
128 var action_type = table[1]
129 var action_value = table[2]
132 var high = table.length/3 - 1
135 var middle = (low + high) / 2
136 var subindex = middle * 3
138 if index < table[subindex] then
140 else if index > table[subindex] then
143 action_type = table[subindex + 1]
144 action_value = table[subindex + 2]
145 high = low -1 # break
149 if action_type == 0 then # SHIFT
150 push(action_value, lexer.next)
151 else if action_type == 1 then # REDUCE
152 _reduce_table[action_value].action(self)
153 else if action_type == 2 then # ACCEPT
154 var node2 = lexer.next
157 assert node1 isa ${/parser/prods/prod/@ename}
158 var node = new Start(node1, node2)
159 (new SearchTokensVisitor).visit(node)
161 else if action_type == 3 then # ERROR
162 var node2 = new PError.init_error(lexer.filename, last_line, last_pos, error_messages[errors[action_value]])
163 var node = new Start(null, node2)
170 attr _reduce_table: Array[ReduceAction]
171 private meth build_reduce_table
173 _reduce_table = new Array[ReduceAction].with(
174 $ foreach {rules/rule}
175 new ReduceAction@index[-sep ','-]
181 # Find first and last tokens of production nodes
182 private class SearchTokensVisitor
184 attr _untokenned_nodes: Array[Prod]
185 attr _last_token: Token
186 redef meth visit(n: PNode)
191 for no in _untokenned_nodes do
194 _untokenned_nodes.clear
197 _untokenned_nodes.add(n)
199 n.last_token = _last_token
204 _untokenned_nodes = new Array[Prod]
208 # Each reduca action has its own class, this one is the root of the hierarchy.
209 private abstract class ReduceAction
210 meth action(p: Parser) is abstract
213 $ foreach {rules/rule}
214 private class ReduceAction@index
216 redef meth action(p: Parser)
218 var node_list: Object = null
222 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = p.pop
224 $ when {@cmd='FETCHLIST'}
225 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@from,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
226 assert ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} isa Array[Object]
228 $ when {@cmd='FETCHNODE'}
229 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = ${translate(@from,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
230 assert ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} isa @etype
232 $ when {@cmd='ADDNODE'}
233 if ${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} != null then
234 ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}.add(${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")})
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")}
242 ${translate(@tolist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}.append(${translate(@fromlist,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")})
246 $ when {@cmd='MAKELIST'}
247 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = new Array[Object]
249 $ when {@cmd='MAKENODE'}
250 var ${translate(@result,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")} = new @etype.init_${translate(@etype,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}(
255 ${translate(.,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}[-sep ','-]
260 $ when {@cmd='RETURNNODE'}
264 node_list = ${translate(@node,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
267 $ when {@cmd='RETURNLIST'}
268 node_list = ${translate(@list,"ABCDEFGHIJKLMNOPQRSTUVWXYZ","abcdefghijklmnopqrstuvwxyz")}
272 p.push(p.go_to(@leftside), node_list)
279 $ template make_parser_tables()
280 # Parser that build a full AST
282 attr _action_table: Array[Array[Int]]
283 private meth build_action_table
285 _action_table = once [
286 $ foreach {parser_data/action_table/row}
287 action_table_row${position()}[-sep ','-]
292 $ foreach {parser_data/action_table/row}
293 private meth action_table_row${position()}: Array[Int]
297 @from, @action, @to [-sep ','-]
303 attr _goto_table: Array[Array[Int]]
304 private meth build_goto_table
307 $ foreach {parser_data/goto_table/row}
310 @from, @to [-sep ','-]
317 private meth error_messages: Array[String]
320 $ foreach {parser_data/error_messages/msg}
321 "${sablecc:string2escaped_unicode(.)}" [-sep ','-]
326 private meth errors: Array[Int]
329 [-foreach {parser_data/errors/i}-]${.} [-sep ','-] [-end-]