introspection

问题 How can I determine programmatically if one function calls another function? I cannot modify either function. Here's what I want ( source_calls_target ): >>> def check(): >>> pass >>> def test_check(): >>> check() >>> def source_calls_target(source, target): >>> # if source() calls target() somewhere, return True >>> ??? >>> source_calls_target(test_check, check) True >>> source_calls_target(check, test_check) False Ideally, I do not want to actually call target() . Ideally, I want to check

问题 Consider the example class FooListener extends Listener { @Listen def runMeToo = { ... } } trait Listener { @Listen def runMe = { ... } } I'm writing introspection code to find all methods of a given class (ie FooListener ) annotated with a certain annotation (ie @Listen ). They'll be invoked under certain circumstances. So I need all their java.lang.Method instances. It's easy to find those methods in the FooListener class. Easy also to find those of the super classes. The question is how to

问题 I have an iPad app where I have a view controller that is the UIGestureRecognizerDelegate for a number of UIGestureRecognizers. I have implemented the following method of UIGestureRecognizerDelegate: - (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch { // Double tapping anywhere on the screen hides/shows the toolbar if ([gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]] == YES) { if (touch.tapCount == 2) { self.toolbar.hidden =

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 3 years ago . Many languages have the ability for introspection and reflection. However, some are clearly better than others. Any suggestions as to which languages are "better" in this respect, and why. 回答1: Reflection is essentially the ability to extract properties of the source program.

问题 In source examples and SO answers that have some degree of Python object introspection, a common pattern is: getattr(some_object, attribute_name_string) Is there a reason why this pattern is preferred to: some_object.__dict__[attribute_name_string] which seems to be more directly showing what's going on? Is it because the latter is too close to a particular implementation in CPython that may be subject to change? NB Original question incorrectly identified the popular idiom as: some_object._

问题 There are two files: # the_imported.py import inspect imported_by_fname = inspect.currentframe().f_back.f_code.co_filename print('{} was imported by {}'.format(__name__, imported_by_fname)) And: # the_importer.py import the_imported When executed with Python 2.7: $ python the_importer.py the_imported was imported by the_importer.py When executed with Python 3.5: $ python3 the_importer.py the_imported was imported by <frozen importlib._bootstrap> What is that weird thing <frozen importlib.

问题 My question is somewhat similar to this one; it concerns object methods rather than module contents. I want to know if I can use the inspect module to get the methods defined only in the class I'm asking about , and not its parent(s). I need this because my child class defines 'macro' methods, which accesses the parent's methods at a higher level of abstraction, and I don't want the user to have to worry about the lower-level methods defined all the way up the inheritance tree. Here is a

问题 I'm facing situations where i'm finding it handy to store the type (as an enum) of an object in the base class to further cast a pointer to that base class into a subclass pointer depending on the value of that type. For example : class CToken { public: token_type_e eType; }; class COperatorToken : public CToken { public: // Sub class specific stuff }; class CLiteralToken : public CToken { public: // Sub class specific stuff }; And then vector<CToken *> aTokens; //... for( size_t nI = 0,

问题 This is a two-part question about blocks (^{}) in Objective-C . I have searched for some answers, but nothing has showed up in Google or SO. This question stems from a desire to create an custom XML Layout Engine for iOS, with support for blocks - meaning that I want to parse NSStrings and create a block during runtime. 1) Is this even possible? If so, how can it be done? Not being able to find much on NSString to Block , I thought that the reason may be how a block is handled by the compiler

问题 Given a class C with a function or method f , I use inspect.ismethod(obj.f) (where obj is an instance of C ) to find out if f is bound method or not. Is there a way to do the same directly at the class level (without creating an object)? inspect.ismethod does not work as this: class C(object): @staticmethod def st(x): pass def me(self): pass obj = C() results in this (in Python 3): >>> inspect.ismethod(C.st) False >>> inspect.ismethod(C.me) False >>> inspect.ismethod(obj.st) False >>> inspect