Beginning Perl (free) - www.perl.org by Simon Cozens What does this book cover? Installing Perl on Windows and UNIX Making use of online Perl resources like CPAN First principles in programming and the Perl syntax Working with files and databases Writing web pages in Perl Using Perl as an object-oriented language Book overview Perl is a well-established programming language that has been developed through the time and effort of countless free software programmers into an immensely powerful tool that can be used on pratically every operating system in the world. "There's more than one way to do it" is the motto of Perl, but this book aims to take you through them all. Who is this book for? This book is for those new to programming who want to learn with Perl.
Cassandra vs MongoDB vs CouchDB vs Redis vs Riak vs HBase vs Couchbase vs Hypertable vs ElasticSearch vs Accumulo vs VoltDB vs Scalaris comparison :: Software architect Kristof Kovacs While SQL databases are insanely useful tools, their monopoly in the last decades is coming to an end. And it's just time: I can't even count the things that were forced into relational databases, but never really fitted them. (That being said, relational databases will always be the best for the stuff that has relations.) But, the differences between NoSQL databases are much bigger than ever was between one SQL database and another. This means that it is a bigger responsibility on software architects to choose the appropriate one for a project right at the beginning. In this light, here is a comparison of Open Source NOSQL databases: The most popular ones # Redis # Best used: For rapidly changing data with a foreseeable database size (should fit mostly in memory). For example: To store real-time stock prices. Cassandra # Best used: When you need to store data so huge that it doesn't fit on server, but still want a friendly familiar interface to it. MongoDB # ElasticSearch # CouchDB # Accumulo #
Discover Everything through Code Kinect for Windows SDK Beta 2 Quickstarts 8 minutes, 56 seconds 6 minutes, 50 seconds 12 minutes, 16 seconds 15 minutes, 36 seconds 16 minutes, 57 seconds 11 minutes, 48 seconds Home | kiuwan.com | Cloud-based Code Quality and Security 7 Patterns to Refactor Fat ActiveRecord Models When teams use Code Climate to improve the quality of their Rails applications, they learn to break the habit of allowing models to get fat. “Fat models” cause maintenance issues in large apps. Only incrementally better than cluttering controllers with domain logic, they usually represent a failure to apply the Single Responsibility Principle (SRP). Early on, SRP is easier to apply. As you add more intrinsic complexity (read: features!) You may be thinking: “But Rails makes it really hard to do OOP right!” I used to believe that too. Don’t Extract Mixins from Fat Models Let’s get this out of the way. “Any application with an app/concerns directory is concerning.” And I agree. Now on to the refactorings! 1. Value Objects are simple objects whose equality is dependent on their value rather than an identity. In Rails, Value Objects are great when you have an attribute or small group of attributes that have logic associated with them. The #worse_than? 2. 3. 4. 5. 6. 7. Wrapping Up P.S.
Single responsibility principle In object-oriented programming, the single responsibility principle states that every context (class, function, variable, etc.) should define a single responsibility, and that responsibility should be entirely encapsulated by the context. All its services should be narrowly aligned with that responsibility. Martin defines a responsibility as a reason to change, and concludes that a class or module should have one, and only one, reason to change. As an example, consider a module that compiles and prints a report. Such a module can be changed for two reasons. The reason it is important to keep a class focused on a single concern is that it makes the class more robust. The responsibility is defined as a charge assigned to a unique actor to signify its accountabilities concerning a unique business task.[4] References[edit]
SOLID (object-oriented design) In computer programming, SOLID (Single responsibility, Open-closed, Liskov substitution, Interface segregation and Dependency inversion) is a mnemonic acronym introduced by Michael Feathers for the "first five principles" named by Robert C. Martin[1][2] in the early 2000s[3] that stands for five basic principles of object-oriented programming and design. The principles when applied together intend to make it more likely that a programmer will create a system that is easy to maintain and extend over time.[3] The principles of SOLID are guidelines that can be applied while working on software to remove code smells by causing the programmer to refactor the software's source code until it is both legible and extensible. It is part of an overall strategy of agile and adaptive programming.[3]
Practical Fluid Mechanics (This article originally appeared in two parts in Game Developer Magazine, March and April, 2007) Fluid effects such as rising smoke and turbulent water flow are everywhere in nature, but are seldom implemented convincingly in computer games. The simulation of fluids (which covers both liquids and gasses) is computationally very expensive. It is also mentally very expensive, with even introductory papers on the subject relying on the reader having math skills at least at the undergraduate calculus level. In this article I will attempt to address both these problems from the perspective of a game programmer not necessarily conversant with vector calculus. There are several ways of simulating the motion of fluids. It is simplest to discuss the grid methods with respect to a regular two-dimensional grid, although the techniques apply equally well to three dimensions. In addition to these two grids we can have any number of other matching grids that store various attributes.