1 # This file is part of NIT ( http://www.nitlanguage.org ).
3 # Copyright 2012 Jean Privat <jean@pryen.org>
5 # Licensed under the Apache License, Version 2.0 (the "License");
6 # you may not use this file except in compliance with the License.
7 # You may obtain a copy of the License at
9 # http://www.apache.org/licenses/LICENSE-2.0
11 # Unless required by applicable law or agreed to in writing, software
12 # distributed under the License is distributed on an "AS IS" BASIS,
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 # See the License for the specific language governing permissions and
15 # limitations under the License.
17 # Identification and scping of local variables and labels.
24 redef class ToolContext
25 var scope_phase
: Phase = new ScopePhase(self, null)
28 private class ScopePhase
30 redef fun process_npropdef
(npropdef
) do npropdef
.do_scope
(toolcontext
)
34 # A local variable (including parameters, automatic variables and self)
36 # The name of the variable (as used in the program)
40 redef fun to_s
do return self.name
43 # Mark where break and continue will branch.
44 # Marks are either associated with a label of with a for_loop structure
46 # The name of the label (unless the mark is an anonymous loop mark)
47 var name
: nullable String
49 # Is the mark atached to a loop (loop, while, for)
50 # Such a mark is a candidate to a labelless 'continue' or 'break'
53 # Each 'continue' attached to the mark
54 var continues
: Array[AContinueExpr] = new Array[AContinueExpr]
56 # Each 'break' attached to the mark
57 var breaks
: Array[ABreakExpr] = new Array[ABreakExpr]
60 # Visit a npropdef and:
61 # * Identify variables and labels
62 # * Associate each break and continue to its escapemark
63 # * Transform `ACallFormExpr` that access a variable into `AVarFormExpr`
64 # FIXME: Should the class be private?
65 private class ScopeVisitor
68 # The tool context used to display errors
69 var toolcontext
: ToolContext
71 var selfvariable
: Variable = new Variable("self")
73 init(toolcontext
: ToolContext)
75 self.toolcontext
= toolcontext
79 # All stacked scope. `scopes.first` is the current scope
80 private var scopes
: List[Scope] = new List[Scope]
82 # Regiter a local variable.
83 # Display an error on toolcontext if a variable with the same name is masked.
84 fun register_variable
(node
: ANode, variable
: Variable): Bool
86 var name
= variable
.name
87 var found
= search_variable
(name
)
89 self.error
(node
, "Error: A variable named `{name}' already exists")
92 scopes
.first
.variables
[name
] = variable
96 # Look for a variable named `name`.
97 # Return null if no such a variable is found.
98 fun search_variable
(name
: String): nullable Variable
100 for scope
in scopes
do
101 var res
= scope
.get_variable
(name
)
111 n
.accept_scope_visitor
(self)
114 # Enter in a statement block `node` as inside a new scope.
115 # The block can be optionally attached to an `escapemark`.
116 private fun enter_visit_block
(node
: nullable AExpr, escapemark
: nullable EscapeMark)
118 if node
== null then return
119 var scope
= new Scope
120 scope
.escapemark
= escapemark
121 scopes
.unshift
(scope
)
126 # Look for a label `name`.
127 # Return nulll if no such a label is found.
128 private fun search_label
(name
: String): nullable EscapeMark
130 for scope
in scopes
do
131 var res
= scope
.escapemark
132 if res
!= null and res
.name
== name
then
139 # Create a new escape mark (possibly with a label)
140 # Display an error on toolcontext if a label with the same name is masked.
141 private fun make_escape_mark
(nlabel
: nullable ALabel, for_loop
: Bool): EscapeMark
143 var name
: nullable String
144 if nlabel
!= null then
145 var nid
= nlabel
.n_id
147 var res
= search_label
("")
149 self.error
(nlabel
, "Syntax error: anonymous label already defined.")
154 var found
= self.search_label
(name
)
155 if found
!= null then
156 self.error
(nlabel
, "Syntax error: label {name} already defined.")
162 var res
= new EscapeMark(name
, for_loop
)
166 # Look for an escape mark optionally associated with a label.
167 # If a label is given, the the escapemark of this label is returned.
168 # If there is no label, the nearest escapemark that is `for loop` is returned.
169 # If there is no valid escapemark, then an error is displayed ans null is returned.
170 # Return nulll if no such a label is found.
171 private fun get_escapemark
(node
: ANode, nlabel
: nullable ALabel): nullable EscapeMark
173 if nlabel
!= null then
174 var nid
= nlabel
.n_id
176 var res
= search_label
("")
178 self.error
(nlabel
, "Syntax error: invalid anonymous label.")
184 var res
= search_label
(name
)
186 self.error
(nlabel
, "Syntax error: invalid label {name}.")
191 for scope
in scopes
do
192 var res
= scope
.escapemark
197 self.error
(node
, "Syntax Error: 'break' statment outside block.")
203 private fun error
(node
: ANode, message
: String)
205 self.toolcontext
.error
(node
.hot_location
, message
)
210 var variables
: HashMap[String, Variable] = new HashMap[String, Variable]
212 var escapemark
: nullable EscapeMark = null
214 fun get_variable
(name
: String): nullable Variable
216 if self.variables
.has_key
(name
) then
217 return self.variables
[name
]
225 private fun accept_scope_visitor
(v
: ScopeVisitor)
232 # Entry point of the scope analysis
233 fun do_scope
(toolcontext
: ToolContext)
235 var v
= new ScopeVisitor(toolcontext
)
241 # The variable associated with the parameter
242 var variable
: nullable Variable
243 redef fun accept_scope_visitor
(v
)
247 var variable
= new Variable(nid
.text
)
248 v
.register_variable
(nid
, variable
)
249 self.variable
= variable
253 redef class AVardeclExpr
254 # The variable associated with the variable declaration
255 var variable
: nullable Variable
256 redef fun accept_scope_visitor
(v
)
260 var variable
= new Variable(nid
.text
)
261 v
.register_variable
(nid
, variable
)
262 self.variable
= variable
266 redef class ASelfExpr
267 # The variable associated with the self reciever
268 var variable
: nullable Variable
269 redef fun accept_scope_visitor
(v
)
272 self.variable
= v
.selfvariable
276 redef class AContinueExpr
277 # The escape mark associated with the continue
278 var escapemark
: nullable EscapeMark
279 redef fun accept_scope_visitor
(v
)
282 var escapemark
= v
.get_escapemark
(self, self.n_label
)
283 if escapemark
== null then return # Skip error
284 if not escapemark
.for_loop
then
285 v
.error
(self, "Error: cannot 'continue', only 'break'.")
287 escapemark
.continues
.add
(self)
288 self.escapemark
= escapemark
292 redef class ABreakExpr
293 # The escape mark associated with the break
294 var escapemark
: nullable EscapeMark
295 redef fun accept_scope_visitor
(v
)
298 var escapemark
= v
.get_escapemark
(self, self.n_label
)
299 if escapemark
== null then return # Skip error
300 escapemark
.breaks
.add
(self)
301 self.escapemark
= escapemark
307 # The escape mark associated with the 'do' block
308 var escapemark
: nullable EscapeMark
309 redef fun accept_scope_visitor
(v
)
311 self.escapemark
= v
.make_escape_mark
(n_label
, false)
312 v
.enter_visit_block
(n_block
, self.escapemark
)
317 redef fun accept_scope_visitor
(v
)
319 v
.enter_visit
(n_expr
)
320 v
.enter_visit_block
(n_then
, null)
321 v
.enter_visit_block
(n_else
, null)
325 redef class AWhileExpr
326 # The escape mark associated with the 'while'
327 var escapemark
: nullable EscapeMark
328 redef fun accept_scope_visitor
(v
)
330 var escapemark
= v
.make_escape_mark
(n_label
, true)
331 self.escapemark
= escapemark
332 v
.enter_visit
(n_expr
)
333 v
.enter_visit_block
(n_block
, escapemark
)
337 redef class ALoopExpr
338 # The escape mark associated with the 'loop'
339 var escapemark
: nullable EscapeMark
340 redef fun accept_scope_visitor
(v
)
342 var escapemark
= v
.make_escape_mark
(n_label
, true)
343 self.escapemark
= escapemark
344 v
.enter_visit_block
(n_block
, escapemark
)
349 # The automatic variables in order
350 var variables
: nullable Array[Variable]
352 # The escape mark associated with the 'for'
353 var escapemark
: nullable EscapeMark
355 redef fun accept_scope_visitor
(v
)
357 v
.enter_visit
(n_expr
)
359 # Protect automatic variables
360 v
.scopes
.unshift
(new Scope)
362 # Create the automatic variables
363 var variables
= new Array[Variable]
364 self.variables
= variables
366 var va
= new Variable(nid
.text
)
367 v
.register_variable
(nid
, va
)
371 var escapemark
= v
.make_escape_mark
(n_label
, true)
372 self.escapemark
= escapemark
373 v
.enter_visit_block
(n_block
, escapemark
)
379 redef class AVarFormExpr
380 # The associated variable
381 var variable
: nullable Variable
384 redef class ACallFormExpr
385 redef fun accept_scope_visitor
(v
)
387 if n_expr
isa AImplicitSelfExpr then
389 var variable
= v
.search_variable
(name
)
390 if variable
!= null then
392 if not n_args
.n_exprs
.is_empty
or n_args
isa AParExprs then
393 v
.error
(self, "Error: {name} is variable, not a function.")
396 n
= variable_create
(variable
)
397 n
.variable
= variable
399 n
.accept_scope_visitor
(v
)
407 # Create a variable acces corresponding to the call form
408 private fun variable_create
(variable
: Variable): AVarFormExpr is abstract
411 redef class ACallExpr
412 redef fun variable_create
(variable
)
414 return new AVarExpr.init_avarexpr
(n_id
)
418 redef class ACallAssignExpr
419 redef fun variable_create
(variable
)
421 return new AVarAssignExpr.init_avarassignexpr
(n_id
, n_assign
, n_value
)
425 redef class ACallReassignExpr
426 redef fun variable_create
(variable
)
428 return new AVarReassignExpr.init_avarreassignexpr
(n_id
, n_assign_op
, n_value
)