# Identification and scping of local variables and labels.
module scope
-import parser
-import toolcontext
+import phase
+
+redef class ToolContext
+ var scope_phase: Phase = new ScopePhase(self, null)
+end
+
+private class ScopePhase
+ super Phase
+ redef fun process_npropdef(npropdef) do npropdef.do_scope(toolcontext)
+end
+
# A local variable (including parameters, automatic variables and self)
class Variable
# The name of the variable (as used in the program)
var name: String
- # Alias of `name'
+ # Alias of `name`
redef fun to_s do return self.name
end
-# A local variable associated to a closure definition
-class ClosureVariable
- super Variable
-end
-
# Mark where break and continue will branch.
# Marks are either associated with a label of with a for_loop structure
class EscapeMark
# The name of the label (unless the mark is an anonymous loop mark)
var name: nullable String
- # Is the mark atached to a loop (loop, while, for, closure)
+ # Is the mark atached to a loop (loop, while, for)
# Such a mark is a candidate to a labelless 'continue' or 'break'
var for_loop: Bool
end
# Visit a npropdef and:
-# * Identify variables, closures and labels
+# * Identify variables and labels
# * Associate each break and continue to its escapemark
-# * Transform ACallFormExpr that access a variable into AVarFormExpr
-# * Transform ACallFormExpr that call a closure into AClosureCallExpr
+# * Transform `ACallFormExpr` that access a variable into `AVarFormExpr`
# FIXME: Should the class be private?
private class ScopeVisitor
super Visitor
scopes.add(new Scope)
end
- # All stacked scope. `scopes.first' is the current scope
+ # All stacked scope. `scopes.first` is the current scope
private var scopes: List[Scope] = new List[Scope]
# Regiter a local variable.
return true
end
- # Look for a variable named `name'.
+ # Look for a variable named `name`.
# Return null if no such a variable is found.
fun search_variable(name: String): nullable Variable
do
return null
end
- redef fun visit(n: nullable ANode)
+ redef fun visit(n)
do
n.accept_scope_visitor(self)
end
- # Enter in a statement block `node' as inside a new scope.
- # The block can be optionally attached to an `escapemark'.
+ # Enter in a statement block `node` as inside a new scope.
+ # The block can be optionally attached to an `escapemark`.
private fun enter_visit_block(node: nullable AExpr, escapemark: nullable EscapeMark)
do
if node == null then return
scopes.shift
end
- # Look for a label `name'.
+ # Look for a label `name`.
# Return nulll if no such a label is found.
private fun search_label(name: String): nullable EscapeMark
do
# Display an error on toolcontext if a label with the same name is masked.
private fun make_escape_mark(nlabel: nullable ALabel, for_loop: Bool): EscapeMark
do
- assert named_or_for_loop: nlabel != null or for_loop
var name: nullable String
if nlabel != null then
- name = nlabel.n_id.text
- var found = self.search_label(name)
- if found != null then
- self.error(nlabel, "Syntax error: label {name} already defined.")
+ var nid = nlabel.n_id
+ if nid == null then
+ var res = search_label("")
+ if res != null then
+ self.error(nlabel, "Syntax error: anonymous label already defined.")
+ end
+ name = ""
+ else
+ name = nid.text
+ var found = self.search_label(name)
+ if found != null then
+ self.error(nlabel, "Syntax error: label {name} already defined.")
+ end
end
else
name = null
# Look for an escape mark optionally associated with a label.
# If a label is given, the the escapemark of this label is returned.
- # If there is no label, the nearest escapemark that is `for loop' ir returned.
+ # If there is no label, the nearest escapemark that is `for loop` is returned.
# If there is no valid escapemark, then an error is displayed ans null is returned.
# Return nulll if no such a label is found.
private fun get_escapemark(node: ANode, nlabel: nullable ALabel): nullable EscapeMark
do
if nlabel != null then
- var name = nlabel.n_id.text
+ var nid = nlabel.n_id
+ if nid == null then
+ var res = search_label("")
+ if res == null then
+ self.error(nlabel, "Syntax error: invalid anonymous label.")
+ return null
+ end
+ return res
+ end
+ var name = nid.text
var res = search_label(name)
if res == null then
self.error(nlabel, "Syntax error: invalid label {name}.")
else
for scope in scopes do
var res = scope.escapemark
- if res != null and res.for_loop then
+ if res != null then
return res
end
end
end
end
-redef class AClosureDecl
- # The variable associated with the closure declaration
- var variable: nullable ClosureVariable
- redef fun accept_scope_visitor(v)
- do
- var nid = self.n_id
- var variable = new ClosureVariable(nid.text)
- v.register_variable(nid, variable)
- self.variable = variable
- end
-end
-
redef class AVardeclExpr
# The variable associated with the variable declaration
var variable: nullable Variable
var escapemark: nullable EscapeMark
redef fun accept_scope_visitor(v)
do
- if n_label != null then
- self.escapemark = v.make_escape_mark(n_label, false)
- end
+ self.escapemark = v.make_escape_mark(n_label, false)
v.enter_visit_block(n_block, self.escapemark)
end
end
var variable = v.search_variable(name)
if variable != null then
var n: AExpr
- if variable isa ClosureVariable then
- n = new AClosureCallExpr.init_aclosurecallexpr(n_id, n_args, n_closure_defs)
- n.variable = variable
- else
- if not n_args.n_exprs.is_empty or n_args isa AParExprs then
- v.error(self, "Error: {name} is variable, not a function.")
- return
- end
- n = variable_create(variable)
- n.variable = variable
+ if not n_args.n_exprs.is_empty or n_args isa AParExprs then
+ v.error(self, "Error: {name} is variable, not a function.")
+ return
end
+ n = variable_create(variable)
+ n.variable = variable
replace_with(n)
n.accept_scope_visitor(v)
return
return new AVarReassignExpr.init_avarreassignexpr(n_id, n_assign_op, n_value)
end
end
-
-redef class AClosureCallExpr
- # the associate closure variable
- var variable: nullable ClosureVariable
-end
-
-redef class AClosureDef
- # The automatic variables in order
- var variables: nullable Array[Variable]
-
- # The escape mark used with the closure
- var escapemark: nullable EscapeMark
-
- redef fun accept_scope_visitor(v)
- do
- v.scopes.unshift(new Scope)
-
- var variables = new Array[Variable]
- self.variables = variables
-
- for nid in self.n_ids do
- var va = new Variable(nid.text)
- v.register_variable(nid, va)
- variables.add(va)
- end
-
- var escapemark = v.make_escape_mark(n_label, true)
- self.escapemark = escapemark
- v.enter_visit_block(self.n_expr, escapemark)
-
- v.scopes.shift
- end
-end
nitlanguage / nit.git / blobdiff