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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-3
votes
0answers
8 views

bundle install fail “..does not appear to be a git repository fatal: Could not read from remote repository.”

I have a gem file in which i am trying to get "gem 'twitter-bootstrap-rails', git: 'https://github.com/seyhunak/twitter-bootstrap-rails.git'" using bundle install command and it gives the below error ...
0
votes
0answers
9 views

how to setup a full ruby ecosystem

What are all the tools used when you program in ROR? What I mean by this is, there are many tools used to help a programmer code. He has his text editor, debugger, testing tools (which is a whole ...
23
votes
5answers
8k 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 ...
0
votes
3answers
74 views

Would it be possible to create a language similar to Ruby/Python with static typing that had the speed/memory usage of a compiled C program? [on hold]

One of the main drawbacks of Ruby/Python is performance. I understand that they are interpreted and C is compiled. (And there are things like JRuby which do JIT compilation with Ruby). But they never ...
10
votes
8answers
3k views

How do I design a subclass whose method contradicts its superclass? [duplicate]

How do I design a subclass whose method contradicts its superclass? Let's say we have this example: # Example 1 class Scissor def right_handed? true end end class LeftHandedScissor < ...
5
votes
3answers
651 views

What can procs and lambdas do that functions can't in ruby

I've been working in Ruby for the last couple weeks, and I've come to the subject of procs, lambdas and blocks. After reading a fair share of examples from a variety of sources, I don't how they're ...
1
vote
0answers
37 views

Can someone explain how this ruby basic-calculator code handles addition and subtraction? [migrated]

So I was working on a Codewars problem here, and found some code posted to Github that works out-of-the-box. Problem is, I don't understand how part of it works. Here are the Codewars directions: ...
0
votes
0answers
46 views

better idiom for selecting id of single record matched using alternative primary key? [migrated]

Say I have a model Foo with normal integer primary key (id) and an "alternate" primary key "bar" that's a string. To complicate matters, Foo supports soft deletes, so it has a boolean property ...
8
votes
4answers
1k views

PHP and Ruby: how to leverage both? and, is it worth it?

As you might have noticed from the title, this is not a "PHP or Ruby", or a "PHP vs. Ruby" question. This is a question on how to leverage PHP + Ruby in the same business. I myself am a PHP ...
0
votes
0answers
31 views

Is listing Types in documentation a code smell

I'm documenting a ruby application and looking closely at YARD. I like the increased structure provided over RDoc, but I'm unsure about the Type declaration. In YARD, you can do something like ...
1
vote
2answers
380 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 ...
9
votes
4answers
501 views

Is Non-Deterministic Resource-Management a Leaky Abstraction?

From what I can see, there are two pervasive forms of resource-management: deterministic destruction and explicit. Examples of the former would be C++ destructors and smart pointers or Perl's DESTROY ...
0
votes
2answers
90 views

Refactoring case-when statement [duplicate]

The Product model which can have 2 price tables. The method price calculates the price of the product based on product's price table which is defined by price_table field. class Product < ...
2
votes
1answer
165 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 ...
4
votes
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
votes
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 ...
2
votes
3answers
140 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
vote
0answers
204 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
vote
3answers
61 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
74 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
76 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 ...
2
votes
7answers
8k 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 ...
2
votes
0answers
73 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
301 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
288 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
82 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
88 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
970 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
179 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 ...
8
votes
2answers
360 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
141 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
62 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
66 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
45 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
50 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
vote
1answer
186 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
197 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
67 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
73 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
193 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
160 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
182 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
5k 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
3k 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 ...
29
votes
2answers
3k 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
367 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 = ...
1
vote
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
247 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 ...