You might need to install Gettext and the related PHP library by using your package manager, like apt-get or yum. Here we will also be using Poedit to create translation files. There are three files you usually deal with while working with gettext. There are some cases, in big projects, where you might need to separate translations when the same words convey different meaning given a context. In those cases, you split them into different domains. In Symfony projects, for example, domains are used to separate the translation for validation messages.
A locale is simply a code that identifies one version of a language. It is defined following the ISO and ISO alpha-2 specs: two lower-case letters for the language, optionally followed by an underline and two upper-case letters identifying the country or regional code.
For rare languages , three letters are used. For some speakers, the country part may seem redundant. To use Gettext, we will need to adhere to a specific structure of folders. First, you will need to select an arbitrary root for your l10n files in your source repository. As we said in the introduction, different languages might sport different plural rules. However, gettext saves us from this trouble once again. When creating a new. When calling Gettext in code, you will have to specify the number related to the sentence, and it will work out the correct form to use - even using string substitution if needed.
Plural rules include the number of plurals available and a boolean test with n that would define in which rule the given number falls starting the count with 0. For example:. When calling out Gettext to do localization on sentences with counters, you will have to provide it the related number as well.
Gettext will work out what rule should be in effect and use the correct localized version. You will need to include in the. The first section works like a header, having the msgid and msgstr especially empty. It describes the file encoding, plural forms and other things that are less relevant. The second section translates a simple string from English to Brazilian Portuguese, and the third does the same, but leveraging string replacement from sprintf so the translation may contain the user name and visit date.
The last section is a sample of pluralization forms, displaying the singular and plural version as msgid in English and their corresponding translations as msgstr 0 and 1 following the number given by the plural rule. The plural forms always have two msgid singular and plural , so it is advised not to use a complex language as the source of translation.
As you might have noticed, we are using as source ID the actual sentence in English. That msgid is the same used throughout all your.
The Gettext manual favors the first approach as, in general, it is easier for translators and users in case of trouble. That is how we will be working here as well. However, the Symfony documentation favors keyword-based translation, to allow for independent changes of all translations without affecting templates as well. In a typical application, you would use some Gettext functions while writing static text in your pages.
Those sentences would then appear in. One of the great advantages Gettext has over custom framework i18n packages is its extensive and powerful file format. This guide is based on PoEdit 1. Now, save the file - using that directory structure we mentioned as well.
After setting those points it will run a scan through your source files to find all the localization calls. After every scan PoEdit will display a summary of what was found and what was removed from the source files. Save it and a. As you may have noticed before, there are two main types of localized strings: simple ones and those with plural forms. The first ones have simply two boxes: source and localized string. Tip: you may right-click a translation line and it will hint you with the source files and lines where that string is being used.
On the other hand, plural form strings include two boxes to show the two source strings, and tabs so you can configure the different final forms. Whenever you change your sources and need to update the translations, just hit Refresh and Poedit will rescan the code, removing non-existent entries, merging the ones that changed and adding new ones.
It may also try to guess some translations, based on other ones you did. It is also useful if you have a translation team and someone tries to write something they are not sure about: just mark Fuzzy, and someone else will review later.
From that menu, you can also open parts of the UI that allow you to leave contextual information for translators if needed. It happens the first time it is read, and then, to update it, you might need to restart the server.
Many custom i18n libraries from frameworks use something similar to t as well, to make translated code shorter. However, that is the only function that sports a shortcut. It is just a field in the. You need to include there the specifications of those new functions, following a specific format :.
After including those new rules in the. Dependency injection is a software design pattern that allows the removal of hard-coded dependencies and makes it possible to change them, whether at run-time or compile-time. This quote makes the concept sound much more complicated than it actually is. Dependency Injection is providing a component with its dependencies either through constructor injection, method calls or the setting of properties.
It is that simple. Here we have a Database class that requires an adapter to speak to the database. We instantiate the adapter in the constructor and create a hard dependency. This makes testing difficult and means the Database class is very tightly coupled to the adapter. Now we are giving the Database class its dependency rather than creating it itself.
These are the complex problems that Dependency Injection solves. In terms of Dependency Injection, this means loosening our dependencies by controlling and instantiating them elsewhere in the system. For years, PHP frameworks have been achieving Inversion of Control, however, the question became, which part of control are we inverting, and where to? For example, MVC frameworks would generally provide a super object or base controller that other controllers must extend to gain access to its dependencies.
This is Inversion of Control, however, instead of loosening dependencies, this method simply moved them. Dependency Injection allows us to more elegantly solve this problem by only injecting the dependencies we need, when we need them, without the need for any hard coded dependencies at all.
The Single Responsibility Principle is about actors and high-level architecture. The largest benefit of this approach is that it enables improved code reusability. By designing our class to do just one thing, we can use or re-use it in any other program without changing it.
Practically speaking, this means that we should write classes that implement and adhere to interfaces , then type-hint against those interfaces instead of specific classes. The largest benefit of this approach is that we can very easily extend our code with support for something new without having to modify existing code, meaning that we can reduce QA time, and the risk for negative impact to the application is substantially reduced.
We can deploy new code, faster, and with more confidence. The Liskov Substitution Principle is about subtyping and inheritance. For example, if we have a FileInterface interface which defines an embed method, and we have Audio and Video classes which both implement the FileInterface interface, then we can expect that the usage of the embed method will always do the thing that we intend.
If we later create a PDF class or a Gist class which implement the FileInterface interface, we will already know and understand what the embed method will do. The largest benefit of this approach is that we have the ability to build flexible and easily-configurable programs, because when we change one object of a type e. For example, a Car or Bus class would be interested in a steeringWheel method, but a Motorcycle or Tricycle class would not.
Conversely, a Motorcycle or Tricycle class would be interested in a handlebars method, but a Car or Bus class would not. There is no need to have all of these types of vehicles implement support for both steeringWheel as well as handlebars , so we should break-apart the source interface. The Dependency Inversion Principle is about removing hard-links between discrete classes so that new functionality can be leveraged by passing a different class.
Do not depend on concretions. We can easily refactor the above example to follow this principle. There are several benefits to the Database class now depending on an interface rather than a concretion. Consider that we are working in a team and the adapter is being worked on by a colleague. In our first example, we would have to wait for said colleague to finish the adapter before we could properly mock it for our unit tests. An even bigger benefit to this method is that our code is now much more scalable.
If a year down the line we decide that we want to migrate to a different type of database, we can write an adapter that implements the original interface and injects that instead, no more refactoring would be required as we can ensure that the adapter follows the contract set by the interface. The first thing you should understand about Dependency Injection Containers is that they are not the same thing as Dependency Injection.
A container is a convenience utility that helps us implement Dependency Injection, however, they can be and often are misused to implement an anti-pattern, Service Location.
Injecting a DI container as a Service Locator in to your classes arguably creates a harder dependency on the container than the dependency you are replacing. It also makes your code much less transparent and ultimately harder to test. Most modern frameworks have their own Dependency Injection Container that allows you to wire your dependencies together through configuration.
What this means in practice is that you can write application code that is as clean and de- coupled as the framework it is built on. Many times your PHP code will use a database to persist information. You have a few options to connect and interact with your database. The recommended option until PHP 5. Native drivers are great if you are only using one database in your application, but if, for example, you are using MySQL and a little bit of MSSQL, or you need to connect to an Oracle database, then you will not be able to use the same drivers.
The mysql extension for PHP is incredibly old and has been superseded by two other extensions:. Not only did development stop long ago on mysql , but it was deprecated as of PHP 5. To save digging into your php. Even if you are not using PHP 7. Not only is that a gross oversimplification, it misses out on the advantages that mysqli provides, such as parameter binding, which is also offered in PDO.
More importantly, PDO allows you to safely inject foreign input e. This is possible using PDO statements and bound parameters. This ID should be used to fetch a user record from a database. This is the wrong way to do this:. This is terrible code. You are inserting a raw query parameter into a SQL query. This will get you hacked in a heartbeat, using a practice called SQL Injection.
This is correct code. It uses a bound parameter on a PDO statement. This escapes the foreign input ID before it is introduced to the database preventing potential SQL injection attacks. You should also be aware that database connections use up resources and it was not unheard-of to have resources exhausted if connections were not implicitly closed, however this was more common in other languages. Using PDO you can implicitly close the connection by destroying the object by ensuring all remaining references to it are deleted, i.
When developers first start to learn PHP, they often end up mixing their database interaction up with their presentation logic, using code that might look like this:. While there are many other solutions to doing this - depending on if you prefer OOP or functional programming - there must be some element of separation. That is a good start. Create a simple.
This is essentially the same as what most modern frameworks are doing, albeit a little more manual. You might not need to do all of that every time, but mixing together too much presentation logic and database interaction can be a real problem if you ever want to unit-test your application. Many frameworks provide their own abstraction layer which may or may not sit on top of PDO.
These will often emulate features for one database system that is missing from another by wrapping your queries in PHP methods, giving you actual database abstraction instead of just the connection abstraction that PDO provides. This will of course add a little overhead, but if you are building a portable application that needs to work with MySQL, PostgreSQL and SQLite then a little overhead will be worth it for the sake of code cleanliness.
Some abstraction layers have been built using the PSR-0 or PSR-4 namespace standards so can be installed in any application you like:. Templates provide a convenient way of separating your controller and domain logic from your presentation logic. The main benefit to using templates is the clear separation they create between the presentation logic and the rest of your application.
Templates have the sole responsibility of displaying formatted content. They are not responsible for data lookup, persistence or other more complex tasks.
This leads to cleaner, more readable code which is especially helpful in a team environment where developers work on the server-side code controllers, models and designers work on the client-side code markup. To learn how to create modern pages in SharePoint, check out this post.
I base those on feedback I receive from my clients, by observing what other organizations are doing and of course, my personal preferences, being a pain in the ass minimalist and perfectionist I am. By default, the modern page starts with 1 column layout. However, just as with Wiki pages before, you can separate it into zones. Take advantage of that — use real estate wisely.
The more content you can put in front of my eyes without scrolling, the better! Every modern page has a built-in placeholder for a banner. Banners might make sense on Intranet landing page or some landing pages for some departments i. So I suggest you remove it to gain valuable screen real estate.
Kind of related to Best Practice 1 , I want to see as much info as possible when I make it to your page. Just like you never go to Page 2 or 3 of Google search results, why do you think your colleagues will? If you separate your page into zones, you can now embed web parts without the need to scroll much.
In the old days, almost every Microsoft Site Template contained a document library embedded on the page. Not anymore. Unless your site does not contain any other web parts, do not embed a document library on the modern page. There are so many exciting web parts you can put there instead, like Quick Links, Calendar, embed an image or a video. You can always link to documents from a Quick Launch menu on the left, or create a nice-looking link with an icon using Quick Links web part.
Appointed by the NRC, they were responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.
Finally, I would like to add my personal thanks, in particular to Heidi Schweingruber, without whose wise advice and support I could not have done my part of the job, and to my colleagues on the committee for their enthusiasm, hard work, and collaborative spirit in writing this report. They attended six meetings of two or more days in length, freely provided their comments, engaged in spirited discussion, read and commented on numerous drafts, and worked at a furious pace.
Helen R. Science, engineering, and technology permeate nearly every facet of modern life and hold the key to solving many of humanity's most pressing current and future challenges. The United States' position in the global economy is declining, in part because U. To address the critical issues of U.
A Framework for K Science Education outlines a broad set of expectations for students in science and engineering in grades K These expectations will inform the development of new standards for K science education and, subsequently, revisions to curriculum, instruction, assessment, and professional development for educators. This book identifies three dimensions that convey the core ideas and practices around which science and engineering education in these grades should be built.
These three dimensions are: crosscutting concepts that unify the study of science through their common application across science and engineering; scientific and engineering practices; and disciplinary core ideas in the physical sciences, life sciences, and earth and space sciences and for engineering, technology, and the applications of science.
The overarching goal is for all high school graduates to have sufficient knowledge of science and engineering to engage in public discussions on science-related issues, be careful consumers of scientific and technical information, and enter the careers of their choice.
A Framework for K Science Education is the first step in a process that can inform state-level decisions and achieve a research-grounded basis for improving science instruction and learning across the country. The book will guide standards developers, teachers, curriculum designers, assessment developers, state and district science administrators, and educators who teach science in informal environments.
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Do you enjoy reading reports from the Academies online for free? Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released. Get This Book. Visit NAP. Looking for other ways to read this? No thanks. Page i Share Cite. Suggested Citation: "Front Matter. Property getters and setters. Prototypes, inheritance. Prototypal inheritance. Native prototypes. Class inheritance.
Static properties and methods. Private and protected properties and methods. Extending built-in classes. Class checking: "instanceof".
Error handling. Error handling, "try Custom errors, extending Error. Introduction: callbacks. Promises chaining. Error handling with promises. Generators, advanced iteration. Async iteration and generators. Modules, introduction. Dynamic imports. Browser environment, specs. Node properties: type, tag and contents. Attributes and properties.
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