def test_basic_hook(self):
# define the hook
def threebecomestwo(ast, enc, filename):
class ChangeConstVisitor:
def visitConst(self, node):
if node.value == 3:
node.value = 2
def defaultvisit(self, node):
for child in node.getChildNodes():
child.accept(self)
def __getattr__(self, attrname):
if attrname.startswith('visit'):
return self.defaultvisit
raise AttributeError(attrname)
ast.accept(ChangeConstVisitor())
return ast
# install the hook
import parser
parser.install_compiler_hook(threebecomestwo)
d = {}
exec "a = 3" in d
assert d['a'] == 2 # well, yes ...
def test_removal_of_broken_hooks(self):
def hook(ast, enc, filename):
1/0
import parser
parser.install_compiler_hook(hook)
raises(ZeroDivisionError, "eval('1')")
assert eval("1") == 1
def hook2(ast, enc, filename):
return 1
parser.install_compiler_hook(hook2)
raises(TypeError, "eval('2')")
assert eval("2") == 2
def test_ast_parser(self):
# define the hook
def change_globals(ast, enc, filename):
class ChangeGlobalsVisitor:
def visitConst(self, node):
pass
def defaultvisit(self, node):
for child in node.getChildNodes():
child.accept(self)
def __getattr__(self, attrname):
if attrname.startswith('visit'):
return self.defaultvisit
raise AttributeError(attrname)
ast.accept(ChangeConstVisitor())
return ast
# install the hook
import parser
parser.install_compiler_hook(change_globals)
def test_constant_fold_add(self):
import parser
class Folder(object):
def defaultvisit(self, node):
return node
def __getattr__(self, attrname):
if attrname.startswith('visit'):
return self.defaultvisit
raise AttributeError(attrname)
def visitAdd(self, node):
left = node.left
right = node.right
if isinstance(left, parser.ASTConst) and \
isinstance(right, parser.ASTConst):
if type(left.value) == type(right.value):
return parser.ASTConst(left.value + right.value)
return node
def hook(ast, enc, filename):
return ast.mutate(Folder())
parser.install_compiler_hook(hook)
code = compile("1+2", "", "eval")
parser.install_compiler_hook(None)
import dis, sys, StringIO
s = StringIO.StringIO()
so = sys.stdout
sys.stdout = s
try:
dis.dis(code)
finally:
sys.stdout = so
output = s.getvalue()
assert 'BINARY_ADD' not in output
def test_constant_fold_add(self):
import parser
class Folder:
def defaultvisit(self, node):
return node
def __getattr__(self, attrname):
if attrname.startswith("visit"):
return self.defaultvisit
raise AttributeError(attrname)
def visitAdd(self, node):
left = node.left
right = node.right
if isinstance(left, parser.ASTConst) and isinstance(right, parser.ASTConst):
if type(left.value) == type(right.value):
return parser.ASTConst(left.value + right.value)
return node
def hook(ast, enc, filename):
return ast.mutate(Folder())
parser.install_compiler_hook(hook)
code = compile("1+2", "", "eval")
parser.install_compiler_hook(None)
import dis, sys, StringIO
s = StringIO.StringIO()
so = sys.stdout
sys.stdout = s
try:
dis.dis(code)
finally:
sys.stdout = so
output = s.getvalue()
assert "BINARY_ADD" not in output
def __init__(self):
self.advices = []
self.joinpoints = {}
self._id = 1
parser.install_compiler_hook(self.weave)
import parser
class ConstMutator(parser.ASTMutator):
def visitConst(self, node):
if node.value == 3:
node.value = 2
return node
def threebecomestwo(ast, enc, filename):
ast.mutate(ConstMutator())
return ast
# install the hook
parser.install_compiler_hook(threebecomestwo)
print eval('3*2')
def get_statements(source):
module = source2ast(source)
return module.node.nodes
class Tracer(ASTMutator):
def visitAssName(self, assname):
assign = assname
while not isinstance(assign, ASTAssign):
assign = assign.parent
stmt = assign.parent
varname = assname.name
before_stmts = get_statements(BEFORE_LOG_SOURCE % ((varname,) * 5))
after_stmts = get_statements(AFTER_LOG_SOURCE % (varname, varname))
stmt.insert_before(assign, before_stmts)
stmt.insert_after(assign, after_stmts)
return assname
def _trace(ast, enc, filename):
return ast.accept(Tracer())
install_compiler_hook(_trace)
code = """
a = 3
b = 2
a = 1
"""
exec code
import parser
class ConstMutator(parser.ASTMutator):
def visitConst(self, node):
if node.value == 3:
node.value = 2
return node
def threebecomestwo(ast, enc, filename):
ast.mutate(ConstMutator())
return ast
# install the hook
parser.install_compiler_hook(threebecomestwo)
print eval('3*2')