I want to have a return_empty_set class method in Ruby, similar to the attr_reader methods. My proposed implementation is class Class def return_empty_set *list list.each do |x| class_eval "def #{x}; Set.new; end" end end end and example usage: class Foo return_empty_set :one end Foo.new.one # returns #<Set: {}> ...
Howdy All... first time at stack overflow. I'm looking into using some of the metaprogramming features provided by Ruby or Python, but first I need to know the extent to which they will allow me to extend the language. The main thing I need to be able to do is to rewrite the concept of Class. This doesn't mean that I want to rewrite a...
Here's some simple code that, for each argument specified, will add specific get/set methods named after that argument. If you write attr_option :foo, :bar, then you will see #foo/foo= and #bar/bar= instance methods on Config: module Configurator class Config def initialize() @options = {} end def self.attr_option(*...
In C# I am trying to write code where I would be creating a Func delegate which is in itself generic. For example the following (non-Generic) delegate is returning an arbitrary string: Func<string> getString = () => "Hello!"; I on the other hand want to create a generic which acts similarly to generic methods. For example if I want ...
So I have a series of global functions, say: foo_f1(int a, int b, char *c); foo_f2(int a); foo_f3(char *a); I want to make a C++ wrapper around these, something like: MyFoo::f1(int a, int b, char* c); MyFoo::f2(int a); MyFoo::f3(char* a); There's about 40 functions like this, 35 of them I just want to pass through to the global fu...
Hi, My understanding is that there are two obvious places in a Grails app where one can do meta-programming: The init closure of Bootstrap.groovy The doWithDynamicMethods closure of a plugin The meta-programming I'm referring to here should be visible throughout the metaprogramming, typical examples include adding (or replacing) met...
Hi, I'd want to start using a new system for this project and I was looking for some tools to achieve my goals. Those would be: Data represented under only one form ( only the database schema, or the database itself or whatever) Possibility to easily generate and update other data representations (ex: SQL code & forms from DB schema) ...
I'm learning about metaclasses in Python. I think it is a very powerful technique, and I'm looking for good uses for them. I'd like some feedback of good useful real-world examples of using metaclasses. I'm not looking for example code on how to write a metaclass (there are plenty examples of useless metaclasses out there), but real exam...
Just wondering if it is possible, by some loophole, to define a method name that ends in a colon. The purpose it to make things look like this: mymethod: arg1,arg2,arg3 ...
Greetings, I want to tinker with the global memcache object, and I found the following problems. Cache is a constant Cache is a module I only want to modify the behavior of Cache globally for a small section of code for a possible major performance gain. Since Cache is a module, I can't re-assign it, or encapsulate it. I Would Lik...
Greetings, I've been trying to tinker with a global Cache module, but I can't figure out why this isn't working. Does anyone have any suggestions? This is the error produced for the below code: NameError: undefined method get' for moduleCache' from (irb):21:in `alias_method' module Cache def self.get puts "original" ...
I'm trying to write a DSL that allows me to do Policy.name do author "Foo" reviewed_by "Bar" end The following code can almost process it: class Policy include Singleton def self.method_missing(name,&block) puts name puts "#{yield}" end def self.author(name) puts name end def self.reviewed_by(name) put...
Is there an existing function (in boost mpl or fusion) to splat meta-vector to variadic template arguments? For example: splat<vector<T1, T2, ...>, function>::type // that would be the same as function<T1, T2, ...> My search have not found one, and I do not want to reinvent one if it already exists. Alternatively, is there a solutio...
Is there any way to check if a given function is declared with C-linkage (that is, with extern "C") at compile-time? I am developing a plugin system. Each plugin can supply factory functions to the plugin-loading code. However, this has to be done via name (and subsequent use of GetProcAddress or dlsym). This requires that the functions...
Normally, I might get the metaclass for a particular instance of a Ruby object with something like this: class C def metaclass class << self; self; end end end # This is this instance's metaclass. C.new.metaclass => #<Class:#<C:0x01234567>> # Successive invocations will have different metaclasses, # since they're different ins...
I want to have something like that class A { public: Array& operator()() { . . . } }; class B { public: Element& operator[](int i) { ... } }; template<class T> class execute { public: output_type = operator()(T& t) { if(T == A) Array out = T()(); else { Array res;...
In class Foo I'd like to include method Bar under certain conditions: module Bar def some_method "orly" end end class Foo def initialize(some_condition) if !some_condition "bar" else class << self; include Bar; end end end end Is there any cleaner (and clearer) way to achieve the incl...
One can define a static array at compile time as follows: const std::size_t size = 5; unsigned int list[size] = { 1, 2, 3, 4, 5 }; Question 1 - Is it possible by using various kinds of metaprogramming techniques to assign these values "programmatically" at compile time? Question 2 - Assuming all the values in the array are to be ...
It is said that Ruby is a metaprogramming language. I wonder if the first 3 lines can be made less verbose using metaprogramming? RUBY_VERSION ||= "unknown version" RUBY_PATCHLEVEL ||= "unknown patchlevel" RUBY_PLATFORM ||= "unknown platform" print "Ruby ", RUBY_VERSION, " patch ", RUBY_PATCHLEVEL, " on ", RUBY_PLATFORM ...
hello. In meta-programming number of classes grows quite fast. Is maximum number of classes modern compiler allows, for example g++, something to be concerned about? Thank you ...