As an additional information for future readers, starting from ruby 2.1.0 you can using binding.local_variable_get and binding.local_variable_set: def foo a = 1 b = binding b.local_variable_set(:a, 2) # set existing local variable `a’ b.local_variable_set(:c, 3) # create new local variable `c’ # `c’ exists only in binding. b.local_variable_get(:a) #=> 2 b.local_variable_get(:c) #=> 3 p a … Read more
Take a look at this thread: http://lists.boost.org/boost-users/2009/01/44538.php Derived from the code linked to in that discussion: #include <iostream> template <typename Type> class has_foo { class yes { char m;}; class no { yes m[2];}; struct BaseMixin { void foo(){} }; struct Base : public Type, public BaseMixin {}; template <typename T, T t> class Helper{}; … Read more
I didn’t find anything satisfactory and came up with a prototype that, given the following informal protocol: – (NSString*)concatString:(NSString*)s1 withString:(NSString*)s2; and this C++ code: struct CppClass { std::string concatStrings(const std::string& s1, const std::string& s2) const { return s1+s2; } }; std::string concatStrings(const std::string& s1, const std::string& s2) { return s1+s2; } allows creating and passing … Read more
Python usually doesn’t call the special methods (those with name surrounded by __) on the instance, but only on the class. (Although this is an implementation detail, it’s characteristic of CPython, the standard interpreter.) So there’s no way to override __repr__() directly on an instance and make it work. Instead, you need to do something … Read more
local_variables It outputs array of symbols, presenting variables. In your case: [:a, :b]
You can’t do this exactly, because requiring one file may require others, and Ruby can’t tell the difference between the file that you required and the file that someone else required. You can check out $LOADED_FEATURES for a list of every single thing that’s been required. But you should use Bundler if you want to … Read more
Module inspect from Python’s standard library is your friend — see the online docs! inspect.getargspec(func) returns a tuple with four items, args, varargs, varkw, defaults: len(args) is the “primary arity”, but arity can be anything from that to infinity if you have varargs and/or varkw not None, and some arguments may be omitted (and defaulted) … Read more
Sure it is possible! My solution tests the var by Object#object_id identity: http://codepad.org/V7TXRxmL It’s crippled in the binding passing style … Although it works just for local vars yet, it can be easily be made “universal” adding use of the other scope-variable-listing methods like instance_variables etc. # the function must be defined in such a … Read more
When N2661 was proposed, none of the proposal authors had access to a compiler which implemented constexpr. And none of us were willing to propose something we could not build and test. So whether or not a better design could have been done with constexpr was not even part of the consideration for the design. … Read more
(load-string “(+ 1 2)”)