class SymbolVisitor(Visitor):
def __init__(self, file=stderr):
self.table = SymbolTable(file=file)
self.output = file
@staticmethod
def toTypeList(node):
types = []
if node.name == 'TYPE':
# could have a modifier AND a type
if len(node.children) > 0:
for child in node.children:
if child.data is not None:
types.append(child.data)
else:
types.append(node.data)
return tuple(types)
def visit(self, node):
node.scopestack = tuple(self.table.getCurrentScopeStack())
if node.name == 'DECL':
# DECL is the important one for processing variable instantion
typelist = self.toTypeList(node.children[0])
self.table.enterSymbol(node.children[1].data, typelist)
node.typelist = typelist
super().visit(node)
elif node.name == 'MULTI_ASSIGN' or node.name == 'MULTI':
typelist = node.parent.typelist
# typelist = self.toTypeList(node.children[0])
self.table.enterSymbol(node.children[0].data, typelist)
node.typelist = typelist
super().visit(node)
elif node.name == 'CODEBLOCK':
self.table.openScope()
node.accept(self)
self.table.closeScope()
elif node.name == 'ASSIGN':
# Check for const correctness
# is node.data writable?
syme = self.table.retrieveScope(node.children[0].data)
if syme is None:
# This error will be caught when the recursion to VALUE is found
pass
else:
if 'const' in syme.symtype:
# You cannot change that!!!
print("Symbol %s cannot be assigned in scope %i" % (node.children[0].data, self.table.getCurrentScope()), file=self.output)
self.table.errors = True
node.accept(self)
elif node.name == "VALUE" or node.name == "IDENTIFIER":
# Check that the symbol is accessible in this scope, including const correctness
if type(node.data) is str and self.table.retrieveScope(node.data) is None:
print("The symbol %s is not accessible in scope %i" % (node.data, self.table.getCurrentScope()), file=self.output)
self.table.errors = True
else:
node.accept(self)
return self.table
