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 name
= nlabel
.n_id
.text
146 var found
= self.search_label
(name
)
147 if found
!= null then
148 self.error
(nlabel
, "Syntax error: label {name} already defined.")
153 var res
= new EscapeMark(name
, for_loop
)
157 # Look for an escape mark optionally associated with a label.
158 # If a label is given, the the escapemark of this label is returned.
159 # If there is no label, the nearest escapemark that is `for loop` is returned.
160 # If there is no valid escapemark, then an error is displayed ans null is returned.
161 # Return nulll if no such a label is found.
162 private fun get_escapemark
(node
: ANode, nlabel
: nullable ALabel): nullable EscapeMark
164 if nlabel
!= null then
165 var name
= nlabel
.n_id
.text
166 var res
= search_label
(name
)
168 self.error
(nlabel
, "Syntax error: invalid label {name}.")
173 for scope
in scopes
do
174 var res
= scope
.escapemark
179 self.error
(node
, "Syntax Error: 'break' statment outside block.")
185 private fun error
(node
: ANode, message
: String)
187 self.toolcontext
.error
(node
.hot_location
, message
)
192 var variables
: HashMap[String, Variable] = new HashMap[String, Variable]
194 var escapemark
: nullable EscapeMark = null
196 fun get_variable
(name
: String): nullable Variable
198 if self.variables
.has_key
(name
) then
199 return self.variables
[name
]
207 private fun accept_scope_visitor
(v
: ScopeVisitor)
214 # Entry point of the scope analysis
215 fun do_scope
(toolcontext
: ToolContext)
217 var v
= new ScopeVisitor(toolcontext
)
223 # The variable associated with the parameter
224 var variable
: nullable Variable
225 redef fun accept_scope_visitor
(v
)
229 var variable
= new Variable(nid
.text
)
230 v
.register_variable
(nid
, variable
)
231 self.variable
= variable
235 redef class AVardeclExpr
236 # The variable associated with the variable declaration
237 var variable
: nullable Variable
238 redef fun accept_scope_visitor
(v
)
242 var variable
= new Variable(nid
.text
)
243 v
.register_variable
(nid
, variable
)
244 self.variable
= variable
248 redef class ASelfExpr
249 # The variable associated with the self reciever
250 var variable
: nullable Variable
251 redef fun accept_scope_visitor
(v
)
254 self.variable
= v
.selfvariable
258 redef class AContinueExpr
259 # The escape mark associated with the continue
260 var escapemark
: nullable EscapeMark
261 redef fun accept_scope_visitor
(v
)
264 var escapemark
= v
.get_escapemark
(self, self.n_label
)
265 if escapemark
== null then return # Skip error
266 if not escapemark
.for_loop
then
267 v
.error
(self, "Error: cannot 'continue', only 'break'.")
269 escapemark
.continues
.add
(self)
270 self.escapemark
= escapemark
274 redef class ABreakExpr
275 # The escape mark associated with the break
276 var escapemark
: nullable EscapeMark
277 redef fun accept_scope_visitor
(v
)
280 var escapemark
= v
.get_escapemark
(self, self.n_label
)
281 if escapemark
== null then return # Skip error
282 escapemark
.breaks
.add
(self)
283 self.escapemark
= escapemark
289 # The escape mark associated with the 'do' block
290 var escapemark
: nullable EscapeMark
291 redef fun accept_scope_visitor
(v
)
293 self.escapemark
= v
.make_escape_mark
(n_label
, false)
294 v
.enter_visit_block
(n_block
, self.escapemark
)
299 redef fun accept_scope_visitor
(v
)
301 v
.enter_visit
(n_expr
)
302 v
.enter_visit_block
(n_then
, null)
303 v
.enter_visit_block
(n_else
, null)
307 redef class AWhileExpr
308 # The escape mark associated with the 'while'
309 var escapemark
: nullable EscapeMark
310 redef fun accept_scope_visitor
(v
)
312 var escapemark
= v
.make_escape_mark
(n_label
, true)
313 self.escapemark
= escapemark
314 v
.enter_visit
(n_expr
)
315 v
.enter_visit_block
(n_block
, escapemark
)
319 redef class ALoopExpr
320 # The escape mark associated with the 'loop'
321 var escapemark
: nullable EscapeMark
322 redef fun accept_scope_visitor
(v
)
324 var escapemark
= v
.make_escape_mark
(n_label
, true)
325 self.escapemark
= escapemark
326 v
.enter_visit_block
(n_block
, escapemark
)
331 # The automatic variables in order
332 var variables
: nullable Array[Variable]
334 # The escape mark associated with the 'for'
335 var escapemark
: nullable EscapeMark
337 redef fun accept_scope_visitor
(v
)
339 v
.enter_visit
(n_expr
)
341 # Protect automatic variables
342 v
.scopes
.unshift
(new Scope)
344 # Create the automatic variables
345 var variables
= new Array[Variable]
346 self.variables
= variables
348 var va
= new Variable(nid
.text
)
349 v
.register_variable
(nid
, va
)
353 var escapemark
= v
.make_escape_mark
(n_label
, true)
354 self.escapemark
= escapemark
355 v
.enter_visit_block
(n_block
, escapemark
)
361 redef class AVarFormExpr
362 # The associated variable
363 var variable
: nullable Variable
366 redef class ACallFormExpr
367 redef fun accept_scope_visitor
(v
)
369 if n_expr
isa AImplicitSelfExpr then
371 var variable
= v
.search_variable
(name
)
372 if variable
!= null then
374 if not n_args
.n_exprs
.is_empty
or n_args
isa AParExprs then
375 v
.error
(self, "Error: {name} is variable, not a function.")
378 n
= variable_create
(variable
)
379 n
.variable
= variable
381 n
.accept_scope_visitor
(v
)
389 # Create a variable acces corresponding to the call form
390 private fun variable_create
(variable
: Variable): AVarFormExpr is abstract
393 redef class ACallExpr
394 redef fun variable_create
(variable
)
396 return new AVarExpr.init_avarexpr
(n_id
)
400 redef class ACallAssignExpr
401 redef fun variable_create
(variable
)
403 return new AVarAssignExpr.init_avarassignexpr
(n_id
, n_assign
, n_value
)
407 redef class ACallReassignExpr
408 redef fun variable_create
(variable
)
410 return new AVarReassignExpr.init_avarreassignexpr
(n_id
, n_assign_op
, n_value
)