Do you know if there is a built-in function to build a dictionary from an arbitrary object? I'd like to do something like this: >>> class Foo: ... bar = 'hello' ... baz = 'world' ... >>> f = Foo() >>> props(f) { 'bar' : 'hello', 'baz' : 'world' } NOTE: It should not include methods. Only fields. Thanks ...
I'm new to Ruby, so I'm having some trouble understanding this weird exception problem I'm having. I'm using the ruby-aaws gem to access Amazon ECS: http://www.caliban.org/ruby/ruby-aws/. This defines a class Amazon::AWS:Error: module Amazon module AWS # All dynamically generated exceptions occur within this namespace. # m...
I have a few models that need to have custom find conditions placed on them. For example, if I have a Contact model, every time Contact.find is called, I want to restrict the contacts returned that only belong to the Account in use. I found this via Google (which I've customized a little): def self.find(*args) with_scope(:find => { ...
Given a moderately complex XML structure (dozens of elements, hundreds of attributes) with no XSD and a desire to create an object model, what's an elegant way to avoid writing boilerplate from_xml() and to_xml() methods? For instance, given: <Foo bar="1"><Bat baz="blah"/></Foo> How do I avoid writing endless sequences of: class Fo...
I would like to pass an argument(s) to a method being defined using define_method, how would I do that? ...
Static metaprogramming (aka "template metaprogramming") is a great C++ technique that allows the execution of programs at compile-time. A light bulb went off in my head as soon as I read this canonical metaprogramming example: #include <iostream> using namespace std; template< int n > struct factorial { enum { ret = factorial< n - 1 >...
I am a fan of static metaprogramming in C++. I know Java now has generics. Does this mean that static metaprogramming (i.e., compile-time program execution) is possible in Java? If so, can anyone recommend any good resources where one can learn more about it? ...
I'm trying to polish up my Ruby by re writing Kent Beck's xUnit Python example from "Test Driven Development: By Example". I've got quite far but now I get the following error when I run which I don't grok. C:\Documents and Settings\aharmel\My Documents\My Workspace\TDD_Book\TDDBook_xUnit_RubyVersion\lib\main.rb:21:in `test_running': w...
C++ is probably the most popular language for static metaprogramming and Java doesn't support it. Are there any other languages besides C++ that support generative programming (programs that create programs)? Which ones are the best (for learning, for efficiency, for maintenance, for embedded systems, whatever)? ...
short: Is there a way in Ruby to DRY-ify this: def entry_point_one begin do_something rescue MySyntaxErrorOne, MySyntaxErrorTwo, MySyntaxErrorEtc => syn_err raise syn_err.exception(syn_err.message) end end def entry_point_two begin do_something_else rescue MySyntaxErrorOne, MySyntaxErrorTwo, MySyntaxErrorEtc => s...
I'm currently primarily a D programmer and am looking to add another language to my toolbox, preferably one that supports the metaprogramming hacks that just can't be done in a statically compiled language like D. I've read up on Lisp a little and I would love to find a language that allows some of the cool stuff that Lisp does, but wit...
How can I add an instance variable to a defined class at runtime, and later get and set its value from outside of the class? Edit: It looks like I need to clarify that I'm looking for a metaprogramming solution that allows me to modify the class instance at runtime instead of modifying the source code that originally defined the class. ...
In Ruby for i in A do # some code end is the same as A.each do |i| # some code end for is not a kernel method. What exactly is "for" in ruby Is there a way to use other keywords to so the similar things? Something like total = sum i in I {x[i]} mapping to total = I.sum {|i] x[i]} ...
I am VERY new to ASP.NET. I come from a VB6 / ASP (classic) / SQL Server 2000 background. I am reading a lot about Visual Studio 2008 (have installed it and am poking around). I have read about "reflection" and would like someone to explain, as best as you can to an older developer of the technologies I've written above, what exactly ...
As a programming exercise, I've written a Ruby snippet that creates a class, instantiates two objects from that class, monkeypatches one object, and relies on method_missing to monkeypatch the other one. Here's the deal. This works as intended: class Monkey def chatter puts "I am a chattering monkey!" end def met...
I was looking at the Ruby logging library Logging.logger method and have a question from the source at github relating to this piece of code: logger = ::Logging::Logger.new(name) logger.add_appenders appender logger.additive = false class << logger def close @appenders.each {|a| a.close} h = ::Logging::Repositor...
I'm looking to move some of my lighter weight metaprogramming from Nemerle to Boo and I'm trying to figure out how to define custom operators. For example, I can do the following in Nemerle: macro @<-(func, v) { <[ $func($v) ]> } Then these two are equivalent: foo <- 5; foo(5); I can't find a way of doing this in Boo -- any id...
So $0 is the env variable for the top level Ruby program ... but is there one for the current method? ...
In my experience Meta-templates are really fun (when your compilers are compliant), and can give good performance boosts, and luckily I'm surrounded by seasoned C++ programmers that also grok meta-templates, however occasionally a new developer arrives and can't make heads or tails of some of the meta-template tricks we use (mostly Andre...
Often, programmers write code that generates other code. (The technical term is metaprogramming, but it is more common than merely cross-compilers; think about every PHP web-page that generates HTML or every XSLT file.) One area I find challenging is coming up with techniques to ensure that both the hand-written source file, and the co...