def process(filename):
with open(filename) as file:
text = file.read()
if not text:
raise Exception("Cannot read text from file")
tokenizer = Tokenizer(text)
parser = Parser(tokenizer.create_tokens())
tree = parser.parse()
symbol_table_builder = SemanticAnalyzer()
symbol_table_builder.visit(tree)
class Interpreter(NodeVisitor):
def __init__(self, text):
"""
:param text: client input
"""
self.text = text
self.tokenizer = Tokenizer(self.text)
self.parser = Parser(self.tokenizer.create_tokens())
self.GLOBAL_VARS = dict()
def visit_Program(self, node):
self.visit(node.block)
def visit_Block(self, node):
for declaration in node.declarations:
self.visit(declaration)
self.visit(node.compound_statement)
def visit_VariableDeclaration(self, node):
pass
def visit_Type(self, node):
pass
def visit_Compound(self, node):
for child in node.children:
self.visit(child)
def visit_Assign(self, node):
var_name = node.left.value
self.GLOBAL_VARS[var_name] = self.visit(node.right)
def visit_Var(self, node):
var_name = node.value
val = self.GLOBAL_VARS[var_name]
if val is None:
raise NameError(repr(var_name))
else:
return val
def visit_NoOp(self, node):
pass
def visit_UnaryOp(self, node):
if node.op.type == PLUS:
return +self.visit(node.expr)
elif node.op.type == MINUS:
return -self.visit(node.expr)
def visit_BinOp(self, node):
if node.op.type == PLUS:
return self.visit(node.left) + self.visit(node.right)
elif node.op.type == MINUS:
return self.visit(node.left) - self.visit(node.right)
elif node.op.type == MULTIPLY:
return self.visit(node.left) * self.visit(node.right)
elif node.op.type == INTEGER_DIV:
return self.visit(node.left) // self.visit(node.right)
elif node.op.type == FLOAT_DIV:
return self.visit(node.left) / self.visit(node.right)
def visit_Num(self, node):
return node.value
def visit_ProcedureDeclaration(self, node):
pass
def error(self):
raise Exception("Interpreter error.")
def interpret(self):
ast = self.parser.parse()
if not ast:
return ""
return self.visit(ast)