1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at
7 # http://www.apache.org/licenses/LICENSE-2.0
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
15 # Runtime library required by parsers and lexers generated by nitcc
18 # A abstract parser engine generated by nitcc
21 # FIXME: provide something better, like a lexer?
22 var tokens
= new List[NToken]
24 # Look at the next token
25 # Used by generated parsers
26 fun peek_token
: NToken do return tokens
.first
28 # Consume the next token
29 # Used by generated parsers
30 fun get_token
: NToken do return tokens
.shift
32 # Consume the next token and shift to the state `dest`.
33 # Used by generated parsers
34 fun shift
(dest
: LRState)
37 #print "shift {t} -> {dest}"
39 state_stack
.push state
43 # After a reduction on `goto` go to the next state
44 # Used by generated parsers
45 fun goto
(goto
: LRGoto)
47 #print "reduce from {state} -> {prod}"
48 state
.goto
(self, goto
)
51 # push a new state on the stack of states (
52 # Used by generated parsers
53 fun push
(dest
: LRState)
55 #print "push prod {prod} -> {dest}"
56 state_stack
.push state
60 # Pop and return the last node
61 # Also pop (and discard) the associated state
62 # Used by generated parsers
65 var res
= node_stack
.pop
66 state
= state_stack
.pop
70 # Produce a parse error and stop the parsing
71 # Used by generated parsers
74 var token
= peek_token
75 print
"* parse error in state {state} on token {token}"
76 print
" expected: {state.error_msg}"
77 print
" node_stack={node_stack.join(", ")}"
78 print
" state_stack={state_stack.join(", ")}"
80 if token
isa NLexerError then
82 token
.error_tree
.items
.add_all
(node_stack
)
84 error
= new NParserError
85 error
.position
= token
.position
86 error
.text
= token
.text
88 error
.error_tree
.items
.add_all
(node_stack
)
95 # The stating state for parsing
96 # Used by generated parsers
97 protected fun start_state
: LRState is abstract
100 # Used by generated parsers
109 # Used by generated parsers
110 var node_stack
= new Array[Node]
112 # The stack of states
113 # Used by generated parsers
114 var state_stack
= new Array[LRState]
116 # Should the parser stop
117 # Used by generated parsers
118 var stop
writable = true
120 # Parse a full sequence of tokens and return a complete syntactic tree
128 #print "* current state {state}"
129 #print " tokens={tokens.join(" ")}"
130 #print " node_stack={node_stack.join(" ")}"
131 #print " state_stack={state_stack.join(" ")}"
135 return node_stack
.first
139 # A state in a parser LR automaton generated by nitcc
140 # Used by generated parsers
141 abstract class LRState
142 fun action
(parser
: Parser) is abstract
143 fun goto
(parser
: Parser, goto
: LRGoto) is abstract
144 fun error_msg
: String do return "FIXME"
147 # A concrete production in a parser LR automation generated by nitcc
148 # Used by generated parsers
149 abstract class LRGoto
154 # A abstract lexer engine generated by nitcc
156 # The input stream of characters
159 # The stating state for lexing
160 # Used by generated parsers
161 protected fun start_state
: DFAState is abstract
163 # Lexize a stream of characters and return a sequence of tokens
164 fun lex
: List[NToken]
166 var res
= new List[NToken]
167 var state
= start_state
177 var last_state
: nullable DFAState = null
179 var length
= text
.length
181 if state
.is_accept
then
188 if pos
>= length
then
193 var next
= state
.trans
(c
)
195 if last_state
== null then
196 var token
= new NLexerError
197 var position
= new Position(pos_start
, pos
, line_start
, line
, col_start
, col
)
198 token
.position
= position
199 token
.text
= text
.substring
(pos_start
, pos-pos_start
+1)
203 var position
= new Position(pos_start
, pos_end
, line_start
, line_end
, col_start
, col_end
)
204 var token
= last_state
.make_token
(position
, text
.substring
(pos_start
, pos_end-pos_start
+1))
205 if token
!= null then res
.add
(token
)
206 if pos
>= length
then
208 position
= new Position(pos
, pos
, line
, line
, col
, col
)
209 token
.position
= position
215 pos_start
= pos_end
+ 1
217 line_start
= line_end
237 # A state in a lexer automaton generated by nitcc
238 # Used by generated lexers
240 fun is_accept
: Bool do return false
241 fun trans
(c
: Char): nullable DFAState do return null
242 fun make_token
(position
: Position, text
: String): nullable NToken is abstract
247 # A abstract visitor on syntactic trees generated by nitcc
248 abstract class Visitor
249 # The main entry point to visit a node `n`
250 # Should not be redefined
251 fun enter_visit
(n
: Node)
256 # The specific implementation of a visit
258 # Should be redefined by concrete visitors
260 # Should not be called directly (use `enter_visit` instead)
262 # By default, the visitor just rescursively visit the children of `n`
263 protected fun visit
(n
: Node)
265 n
.visit_children
(self)
269 # Print a node (using to_s) on a line and recustively each children indented (with two spaces)
270 class TreePrinterVisitor
273 private var indent
= 0
274 init(writer
: OStream) do self.writer
= writer
277 for i
in [0..indent
[ do writer
.write
(" ")
286 # A position into a input stream
287 # Used to give position to tokens
295 redef fun to_s
do return "{line_start}:{col_start}-{line_end}:{col_end}"
298 # A node of a syntactic tree
300 # The name of the node (as used in the grammar file)
301 fun node_name
: String do return class_name
303 # A point of view on the direct childrens of the node
304 fun children
: SequenceRead[nullable Node] is abstract
306 # Visit all the children of the node with the visitor `v`
307 protected fun visit_children
(v
: Visitor)
309 for c
in children
do if c
!= null then v
.enter_visit
(c
)
312 # The position of the node in the input stream
313 var position
: nullable Position writable = null
315 # Produce a graphiz file for the syntaxtic tree rooted at `self`.
316 fun to_dot
(filepath
: String)
318 var f
= new OFStream.open
(filepath
)
319 f
.write
("digraph g \{\n")
320 f
.write
("rankdir=BT;\n")
322 var a
= new Array[NToken]
325 f
.write
("\{ rank=same\n")
333 f
.write
("n{n.object_id}")
335 f
.write
("[style=invis];\n")
342 private fun to_dot_visitor
(f
: OStream, a
: Array[NToken])
344 f
.write
("n{object_id} [label=\"{node_name}\
"];\n")
346 if x
== null then continue
347 f
.write
("n{x.object_id} -> n{object_id};\n")
348 x
.to_dot_visitor
(f
,a
)
357 return "{node_name}@({pos})"
362 # A token produced by the lexer and used in a syntactic tree
363 abstract class NToken
366 redef fun children
do return once
new Array[Node]
368 redef fun to_dot_visitor
(f
, a
)
370 var labe
= "{node_name}"
372 if pos
!= null then labe
+= "\\n{pos}"
374 if node_name
!= "'{text}'" then
375 labe
+= "\\n'{text.escape_to_c}'"
377 f
.write
("n{object_id} [label=\"{labe}\
",shape=box];\n")
381 # The text associated with the token
382 var text
: String writable = ""
387 if node_name
!= "'{text}'" then
388 res
+= "='{text.escape_to_c}'"
394 # The special token for the end of stream
399 # A special token used to represent a parser or lexer error
400 abstract class NError
403 # All the partially built tree during parsing (aka the node_stack)
404 var error_tree
= new Nodes[Node]
407 # A lexer error as a token for the unexpected characted
412 # A parser error linked to a unexpected token
415 # The unexpected token
416 var token
: nullable NToken
419 # A hogeneous sequence of node, used to represent unbounded lists (and + modifier)
422 redef fun children
do return items
423 var items
= new Array[T
]
426 # A production with a specific, named and statically typed childrens
429 redef var children
: SequenceRead[nullable Node] = new NProdChildren(self)
431 # The exact number of direct children
432 # Used to implement `children` by generated parsers
433 fun number_of_children
: Int is abstract
435 # The specific children got by its index
436 # Used to implement `children` by generated parsers
437 fun child
(x
: Int): nullable Node is abstract
441 private class NProdChildren
442 super SequenceRead[nullable Node]
444 redef fun iterator
do return new NProdIterator(prod
)
445 redef fun length
do return prod
.number_of_children
446 redef fun is_empty
do return prod
.number_of_children
== 0
447 redef fun [](i
) do return prod
.child
(i
)
450 private class NProdIterator
451 super IndexedIterator[nullable Node]
454 redef fun is_ok
do return index
< prod
.number_of_children
455 redef fun next
do index
+= 1
456 redef fun item
do return prod
.child
(index
)
459 # All-in-one abstract class to test generated parsers on a given
460 abstract class TestParser
461 # How to get a new lexer on a given stream of character
462 fun new_lexer
(text
: String): Lexer is abstract
464 # How to get a new parser
465 fun new_parser
: Parser is abstract
467 # The name of the language (used for generated files)
468 fun name
: String is abstract
470 # Use the class as the main enrty point of the program
471 # - parse arguments and options of the command
472 # - test the parser (see `work`)
475 if args
.is_empty
then
476 print
"usage {name}_test <filepath> | - | -e <text>"
480 var filepath
= args
.shift
482 if filepath
== "-" then
483 text
= stdin
.read_all
484 else if filepath
== "-e" then
485 if args
.is_empty
then
486 print
"Error: -e need a text"
491 var f
= new IFStream.open
(filepath
)
496 if not args
.is_empty
then
497 print
"Error: superfluous arguments."
504 # Produce a full syntactic tree for a given stream of character
505 # Produce also statistics and output files
506 fun work
(text
: String): Node
508 print
"INPUT: {text.length} chars"
509 var l
= new_lexer
(text
)
512 var tokout
= "{name}.tokens.out"
513 print
"TOKEN: {tokens.length} tokens (see {tokout})"
515 var f
= new OFStream.open
(tokout
)
522 p
.tokens
.add_all
(tokens
)
526 var astout
= "{name}.ast.out"
527 f
= new OFStream.open
(astout
)
528 var tpv
= new TreePrinterVisitor(f
)
529 var astdotout
= "{name}.ast.dot"
531 print
"ERROR: {n} (see {astout} and {astdotout})"
535 print
"ROOT: {n} (see {astout} and {astdotout})"