Questions about Ruby, dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features.

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1answer
35 views

Ruby create a class from a specification file

I have a specification file Spec.txt like this title :Test attribute :fieldOne, String attribute :fieldTwo, Fixnum constraint :fieldOne, 'fieldOne != nil' constraint :fieldTwo, 'fieldTwo ...
2
votes
1answer
162 views

How do I distinguish between things belonging to the standard library, specific gems, and those that are user-generated in Ruby?

I'm a beginning programmer, that for various reasons is using an existing Ruby codebase to learn to program. My goal is to be able to understand and eventually extend this codebase. However, I find it ...
0
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0answers
11 views

messages of validation customized in Ruby on rails [migrated]

I have a problem and I don't know to solve this.I have a model called user.rb The model user has a validation of email customized class User < ActiveRecord::Base # Include default devise ...
3
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1answer
3k views

What is a closure and how is it implemented in Ruby?

In the context of the Ruby programming language, what is a closure and when do you use one? What are the uses for it in Rails?
0
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0answers
330 views

Online stores service design [duplicate]

I am designing an online store service app with rails. Everyone who wants to make his/her own store can do it with this app by just signing up and choosing a domain. I want to make it as SaaS as it ...
0
votes
2answers
323 views

How can I rank teams based off of head to head wins/losses

I'm trying to write an algorithm (specifically in Ruby) that will rank teams based on their record against each other. If a team A and team B have won the same amount of games against each other, then ...
0
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0answers
28 views

How best to define classes declaratively in Ruby

Coming from a Perl background I greatly appreciate the Moose/Moo based approach to defining class constructors declaratively. What I mean by that is that with Moose we declare the characteristics of ...
2
votes
3answers
113 views

Which is the convention in Rails to perform calculations and display the results?

So I'm working on a personal project on Rails to learn more about this framework, and I wanted to add a feature in which the user choose a particular record from the view, and after some calculations ...
1
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0answers
160 views

What is the “correct” way to store functions in a database?

Note: Yes, I know that storing functions in databases should be punishable by law. We are developing a financial web application using PostgreSQL, Sinatra and AngularJS. As you may have guessed, a ...
1
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3answers
54 views

Replace repeated timestamp with variable in tests

I have couple hundred tests and I work with date/time a lot. In some tests, I aim for output format, elsewhere, I check date ranges. Therefore, my tests have lots of these: FactoryGirl.create(:foo, ...
2
votes
2answers
69 views

Is a guardfile part of the private developers environment or the public OSS project?

Let us say I have an open source project on github. Now I wish to include tools required to develop the project so others can easily contribute. It is hard for me to tell when these tools should be ...
4
votes
5answers
1k views

How can I move from Java and ColdFusion to Ruby on Rails? [closed]

Currently I work with ColdFusion 9+ and some Java in a Windows environment. Prior to ColdFusion, my background was in Java and JSP. I'm considering a move towards Ruby on Rails, as I think it would ...
1
vote
0answers
54 views

What's the best practice for adding a lot of attributes to a Rails model?

So, I'm building an API wrapper gem that works with Spree's Product model. The API provides extensive customization of the data you send to it. I would like a user of the gem to be able to take ...
17
votes
4answers
7k views

Return random `list` item by its `weight`

I have, for example, this table +-----------------+ | fruit | weight | +-----------------+ | apple | 4 | | orange | 2 | | lemon | 1 | +-----------------+ I need to return random ...
2
votes
7answers
7k views

How much Ruby should I learn before moving to Rails? [closed]

Just a quick question.. I can never get a definitive answer when googling this, either. Some people say you can learn Rails without knowing any Ruby, but at some point you'll run into a brick wall and ...
1
vote
0answers
69 views

Writing a gem supporting compiled languages with Rake. How to test?

I want to create a gem that extends the functionality of Rake, creating commands for compiling .NET code.* Basically, I want to be able to write a Rakefile like this: desc "Build main executable" ...
1
vote
2answers
257 views

How does the consumer-producer solution work?

I'm only a beginner, and my book doesn't cover this subject. I have researched my problem and found that an implementation of the consumer-producer pattern is the ideal solution, and have Googled it, ...
2
votes
3answers
284 views

Questions for Architecture with Ruby and Java [closed]

I am in the research phase of a project that needs to make use of 3rd party libraries that are in Java so I am stuck using Java to at least a small degree. I am considering implementing Ruby as the ...
0
votes
2answers
71 views

Ruby Terminology Question: Implicit Declaration or no declaration at all?

I have a question, because in most serious sources I read, all say the same No variable is ever declared in Ruby, but still I have doubts, because according to what I was taught in my university ...
-1
votes
1answer
72 views

Is obsolete to study older versions of Ruby and RoR? [closed]

I want to study Ruby and RoR for some things I'll have to make, but almost every book, videos or any kind of source I find is outated, where the most current book I could find (link here) is one of ...
0
votes
3answers
838 views

Why would you want to use an array, or hash as hash key in ruby?

i'm using Ruby 1.9.3 I figured out that you can use an array, or a hash as hash key in ruby: h = Hash.new h[Array.new] = "Why?" h[Array.new] # Output: "Why?" h[Hash.new] = "It doesn't make sense" ...
1
vote
2answers
170 views

In Ruby, change global in thread safe block

In Ruby, I have a use case for a few common configuration options, e.g. NOOP, TRACE, SILENT. Right now I am using local vars instead of globals and passing them around all over the place and it's a ...
2
votes
0answers
76 views

Is this code solid? If it's not why not? And how should the dependencies be managed? [closed]

I am very interested in following the SOLID principles of writing code, but for the life of me I consistently run into more questions than answers. One of the questions I have now related to the code ...
8
votes
2answers
343 views

Why don't Python and Ruby make a distinction between declaring and assigning a value to variables?

Two of the most popular dynamically typed scripting languages, Python and Ruby, do not make a distinction in syntax between the declaration of a variable and assignation of a value to it. That is in ...
0
votes
1answer
139 views

How can I write these services using SOLID and keep them easy to test?

I am trying to write a couple of classes using SOLID principles and having some trouble. The problem is quite simple. I have an application that tracks leads. Leads are created when events are raised ...
1
vote
1answer
60 views

How do rails project know about rake tasks from other repositories

We have a rake task called db:sanity_check which exists in a 'core' repo. Other repositories that we have also show this rake task. But they do not define the rake task. It 'comes' from core' How ...
2
votes
1answer
60 views

BloomFilter in ruby should have k hash functions

I am reading the Bloom Filter implementation written in ruby. It should have k hash functions, but it looks like the same hash function is being used with different seed values. Is this a common way ...
0
votes
1answer
38 views

What would be the return type of a cartesian product of a multiset

I am writing a Multiset in Ruby. The Union, Intersection operations where simple and return a MultiSet. But, I am not sure what the return type of the cartesian product should be, should I return an ...
1
vote
1answer
46 views

Create a collection with “average points” of N items from a pool with items of various points

Let's say I have a question pool to generate exams out of it. Each question contains a difficulty from 1 (hard) to 99 (easy). The questions are available in a hash / array (adapt to your favorite ...
1
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1answer
140 views

Should I use expect or should when writing RSpec specs? [closed]

Please can someone explain to me how I should go about deciding whether to use expect or should syntax for my rspec examples. From my understanding we should no longer be using the 'should' syntax. ...
-1
votes
1answer
169 views

Unevenly distributed random number generation [duplicate]

Let's say I have to generate random number from 1 to 100, however, the probability of each number is not 1/100, but a predefined probability. How to generate that number? I use Ruby/Python.
0
votes
1answer
66 views

Calculate which quantity packages to use based on quantity of bookings

In my app, many appointments can be booked for activities. Each activity has many price packages with a price and a quantity. On showing the cart, I need to work out what combination of packages ...
0
votes
1answer
65 views

Ruby on Rails application interfacing with a Datamax barcode printer [closed]

I am trying to find a standalone way to interface with a Datamax M-Class Mark2 label printer through a Ruby on Rails application. I currently have a solution that is working, which i use javascript to ...
0
votes
1answer
171 views

Refactoring a Single Rails Model with large methods & long join queries trying to do everything

I have a working Ruby on Rails Model that I suspect is inefficient, hard to maintain, and full of unnecessary SQL join queries. I want to optimize and refactor this Model (Quiz.rb) to comply with ...
3
votes
0answers
130 views

Splitting up a Rails/Ruby app onto multiple servers

We recently moved a large application to two machines, both running the same codebase. I. Machine A Web server for public facing application Receives web hook call backs from our ESP Handles a ...
1
vote
0answers
149 views

Run RSpec from within a ruby script while refreshing all ruby configs etc

I'm working with a very large project with tons of established tests that include some reasonably complicated environment setups and what not. I've recently run into a situation testing some ...
30
votes
7answers
4k views

Explanation on how “Tell, Don't Ask” is considered good OO

This blogpost was posted on Hacker News with several upvotes. Coming from C++, most of these examples seem to go against what I've been taught. Such as example #2: Bad: def ...
3
votes
3answers
2k views

Ruby IDE code completion [closed]

I just started writing some ruby in my spare time and am currently using Netbeans 7 with the Ruby and Rails plugin v0.111. I'm primarily a Java programmer coming from IntelliJ and Eclipse. One ...
28
votes
2answers
2k views

Do modern languages still use parser generators?

I was researching about the gcc compiler suite on wikipedia here, when this came up: GCC started out using LALR parsers generated with Bison, but gradually switched to hand-written ...
2
votes
2answers
284 views

What kind of exception to ask for out of range arguments?

What type of exception should I throw? I have a console class which describes rectangle of cells which a user can index by passing in a coordinate: width, height = 80, 25 console = ...
0
votes
2answers
2k views

Why doesn't Ruby have implicit conversion of Fixnum into String?

Ruby normally makes things easy. However, it doesn't allow implicitely converting a number to a string: 2.0.0p247 :010 > "a"+1 TypeError: no implicit conversion of Fixnum into String Why is this ...
1
vote
2answers
244 views

Need advice on design in Ruby On Rails

For personal educational purposes I am making a site for a conference. One of the object that exist in a conference is a session, which has different states and in each state it has slightly different ...
5
votes
5answers
2k views

What is a practical way to debug Rails?

I get the impression that in practice, debuggers are rarely used for Rails applications. (Likewise for other Ruby apps, as well as Python.) We can compare this to the usual practice for Java or ...
0
votes
2answers
231 views

What happened to VM based deployments?

Watched some MountainWest RubyConf 2014 talks and noticed an interesting theme. Many dynamic programming environments back in the old days used to be self-contained VM images, e.g. SmallTalk, ...
27
votes
4answers
3k views

Concrete examples of Python's “only one way to do it” maxim

I am learning Python and am intrigued by the following point in PEP 20 The Zen of Python: There should be one-- and preferably only one --obvious way to do it. Although that way may not be ...
0
votes
1answer
101 views

Android -> Ruby Server Interface -> Mongodb

I've been wrecking my brain about this for a few days. I'll run my scenario by you and hopefully you can help me. In my head this is how it goes: I have an Android App. I want my Android App to make ...
4
votes
3answers
2k views

How can web development bootcamps deliver on their promise? [closed]

I came across the concept of web development bootcamps, these 9-10 week intensive crash courses claim to teach beginners web development and help them get 80k starting salary jobs. Many of you might ...
1
vote
1answer
213 views

Why many Ruby gems won't work on Windows [duplicate]

Most of the gems out there work fine on *nix but not on Windows. First I tried WySQL2, then dosu which shows incompatibility with Ruby 2.0. I tried things on github issues, but no luck. I never had ...
3
votes
1answer
114 views

What does it mean that file IO binary flag is only relevant on Windows

I was reading a question and one of the comments mentioned that "The binary flag is only relevant on Windows". Given the context of the question and answer, I interpret this statement as on ...
75
votes
9answers
39k views

Why is Python used for high-performance/scientific computing (but Ruby isn't)?

There's a quote from a PyCon 2011 talk that goes: At least in our shop (Argonne National Laboratory) we have three accepted languages for scientific computing. In this order they are C/C++, ...