Snippet (programming)
Encyclopedia
Snippet is a programming term for a small region of re-usable source code
, machine code
or text. Ordinarily, these are formally-defined operative units to incorporate into larger programming modules. Snippets are often used to clarify the meaning of an otherwise "cluttered" function, or to minimize the use of repeated code that is common to other functions.
Snippet management is a feature of some text editor
s, program source code editor
s, IDE
s, and related software. It allows the user to persist
and use snippets in the course of routine edit operations.
or boilerplate
). Often this feature is justified because the content varies only slightly (or not at all) each time it is entered.
, catalogue or database
.
, NetBeans
and Microsoft's Visual Studio (a keyword and ) and other IDEs
include built-in parts of structure for ease of coding.
Other applications such as Macromedia Dreamweaver make use of these code snippets as well for Web development
.
) compilers can "splice together" pre-compiled sections of code as longer object code
/machine code
segments. This reduces interpret time significantly and simultaneously speeds execution.
These snippet feature groups include:
Static snippets consist primarily of fixed text that the user can choose to insert into the current document. The user is not able to specify anything else, except perhaps the cursor position relative to the newly inserted text. Static snippets are similar to simple macros.
Dynamic snippets consist of fixed text combined with dynamic elements. The user may specify both the content of the dynamic elements, as well as their position relative to the fixed text, as part of choosing what to insert into the current document. Examples of dynamic elements could be variables such as the current date or system time, or input from the user that is supplied via a GUI, or input from another application. (see also: programmable macro).
Scriptable snippets consist of runnable segments of code in either a macro language or a scripting language
. Scriptable snippets provide the greatest degree of flexibility to the user, although that depends somewhat on the programming languages supported by the text editor, and whether or not the programming language is well-known, or particular and unique to that specific editor.
The type of scripting support varies, but may include features such as running shell command
s, providing a GUI dialog
or other methods of user interaction with the operating system; other applications; or other sub-components of the hosting application itself.
Placeholders may have special markup syntax
that allows the editor to identify the boundaries of placeholders relative to the other text in the current edit buffer.
Other applications employ graphical user interface
s and modal dialog box
es that allow the user to enter one or more values to be supplied for the placeholders.
s. The identifiers may be useful for supporting such features as placeholder duplication or placeholder transformation.
The following example uses the identifiers
One common complication, however, is that environments that support programmable snippets often have to make distinctions between what counts as "plain text" and what counts as "programming instructions". Further complicating this distinction is the fact that applications that support programmable snippets almost always include support for recognition of multiple programming languages, either through basic syntax highlighting
or execution of embedded commands.
For these and other reasons, emitting plain text from programmable snippets almost always entails being careful to avoid problems with syntax
and delimiter collisions.
Scriptable snippets are often associated with one or more currently-active files. Consequently, variables may also include environment variables and arguments that specify the filename, cursor position, parent directory and other stats relating to the files in a current editing session.
s. This may include one or more standalone languages, or a language that is specific to the application in which the language is hosted.
Source code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
, machine code
Machine code
Machine code or machine language is a system of impartible instructions executed directly by a computer's central processing unit. Each instruction performs a very specific task, typically either an operation on a unit of data Machine code or machine language is a system of impartible instructions...
or text. Ordinarily, these are formally-defined operative units to incorporate into larger programming modules. Snippets are often used to clarify the meaning of an otherwise "cluttered" function, or to minimize the use of repeated code that is common to other functions.
Snippet management is a feature of some text editor
Text editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
s, program source code editor
Source code editor
A source code editor is a text editor program designed specifically for editing source code of computer programs by programmers. It may be a standalone application or it may be built into an integrated development environment ....
s, IDE
Integrated development environment
An integrated development environment is a software application that provides comprehensive facilities to computer programmers for software development...
s, and related software. It allows the user to persist
Persistence (computer science)
Persistence in computer science refers to the characteristic of state that outlives the process that created it. Without this capability, state would only exist in RAM, and would be lost when this RAM loses power, such as a computer shutdown....
and use snippets in the course of routine edit operations.
Overview
Snippet management is a text editor feature popular among software developers or others who routinely require content from a catalogue of repeatedly entered text (such as with source codeSource code
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
or boilerplate
Boilerplate (text)
Boilerplate is any text that is or can be reused in new contexts or applications without being changed much from the original. Many computer programmers often use the term boilerplate code. A legal boilerplate is a standard provision in a contract....
). Often this feature is justified because the content varies only slightly (or not at all) each time it is entered.
Snippets in text editors
Text editors that include this feature ordinarily provide a mechanism to manage the catalogue, and separate "snippets" in the same manner that the text editor and operating system allow management of separate files. These basic management abilities include operations such as viewing, adding, editing, deleting, sorting, filtering, grouping, renaming and storing snippets in a repositorySoftware repository
A software repository is a storage location from which software packages may be retrieved and installed on a computer.- Discussion :Many software publishers and other organizations maintain servers on the Internet for this purpose, either free of charge or for a subscription fee...
, catalogue or database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
.
Snippets in IDEs
Some programmer's applications such as EclipseEclipse (software)
Eclipse is a multi-language software development environment comprising an integrated development environment and an extensible plug-in system...
, NetBeans
NetBeans
NetBeans refers to both a platform framework for Java desktop applications, and an integrated development environment for developing with Java, JavaScript, PHP, Python, Groovy, C, C++, Scala, Clojure, and others...
and Microsoft's Visual Studio (a keyword and ) and other IDEs
Integrated development environment
An integrated development environment is a software application that provides comprehensive facilities to computer programmers for software development...
include built-in parts of structure for ease of coding.
Other applications such as Macromedia Dreamweaver make use of these code snippets as well for Web development
Web development
Web development is a broad term for the work involved in developing a web site for the Internet or an intranet . This can include web design, web content development, client liaison, client-side/server-side scripting, web server and network security configuration, and e-commerce development...
.
Snippets in JIT compilers
Just-in-time (JITJIT
JIT may refer to:* Various meanings of Just In Time:** Just-in-time compilation - a technique for improving the performance of virtual machines in computing.** Just-in-time - a business inventory strategy.* Jabber ICQ Transport....
) compilers can "splice together" pre-compiled sections of code as longer object code
Object code
Object code, or sometimes object module, is what a computer compiler produces. In a general sense object code is a sequence of statements in a computer language, usually a machine code language....
/machine code
Machine code
Machine code or machine language is a system of impartible instructions executed directly by a computer's central processing unit. Each instruction performs a very specific task, typically either an operation on a unit of data Machine code or machine language is a system of impartible instructions...
segments. This reduces interpret time significantly and simultaneously speeds execution.
Conventions
In addition to the basic management abilities described previously, snippet management features can be classified according to the scope of interactivity between snippets and the text editor or application that hosts them.These snippet feature groups include:
- plain-text or "static" snippets
- interactive or "dynamic" snippets
- scriptable snippets
Static snippets consist primarily of fixed text that the user can choose to insert into the current document. The user is not able to specify anything else, except perhaps the cursor position relative to the newly inserted text. Static snippets are similar to simple macros.
Dynamic snippets consist of fixed text combined with dynamic elements. The user may specify both the content of the dynamic elements, as well as their position relative to the fixed text, as part of choosing what to insert into the current document. Examples of dynamic elements could be variables such as the current date or system time, or input from the user that is supplied via a GUI, or input from another application. (see also: programmable macro).
Scriptable snippets consist of runnable segments of code in either a macro language or a scripting language
Scripting language
A scripting language, script language, or extension language is a programming language that allows control of one or more applications. "Scripts" are distinct from the core code of the application, as they are usually written in a different language and are often created or at least modified by the...
. Scriptable snippets provide the greatest degree of flexibility to the user, although that depends somewhat on the programming languages supported by the text editor, and whether or not the programming language is well-known, or particular and unique to that specific editor.
The type of scripting support varies, but may include features such as running shell command
Unix shell
A Unix shell is a command-line interpreter or shell that provides a traditional user interface for the Unix operating system and for Unix-like systems...
s, providing a GUI dialog
Dialog box
In a graphical user interface of computers, a dialog box is a type of window used to enable reciprocal communication or "dialog" between a computer and its user. It may communicate information to the user, prompt the user for a response, or both...
or other methods of user interaction with the operating system; other applications; or other sub-components of the hosting application itself.
Snippet placeholders
Placeholders are elements within a snippet that are left to be supplied by the user or other external process. The values for placeholders are not determined until the text of the snippet is inserted during an editing session.Placeholders may have special markup syntax
Markup language
A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts...
that allows the editor to identify the boundaries of placeholders relative to the other text in the current edit buffer.
Other applications employ graphical user interface
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...
s and modal dialog box
Modal window
In user interface design, a modal window is a child window that requires users to interact with it before they can return to operating the parent application, thus preventing the workflow on the application main window...
es that allow the user to enter one or more values to be supplied for the placeholders.
Placeholder identifiers
Placeholders are usually indicated by some special character or sequence of characters to distinguish them from the rest of the snippet text. Some systems allow snippet placeholders to be named identifierIdentifier
An identifier is a name that identifies either a unique object or a unique class of objects, where the "object" or class may be an idea, physical [countable] object , or physical [noncountable] substance...
s. The identifiers may be useful for supporting such features as placeholder duplication or placeholder transformation.
The following example uses the identifiers
first_name, last_name, and item:
Hello {%first_name%} {%last_name%},
Your shipment of {%item%} is now ready to pick up.
Thanks {%first_name%}!
Placeholder duplication
This allows the user to indicate that the value supplied for one placeholder should be replicated in multiple places, relative to the entire text of the programmable snippet. In the previous example, the named placeholderfirst_name is an example of this usage.Placeholder transformation
This allows the user to indicate that one or more values supplied for a placeholder should be replicated and transformed in other places within the text of the programmable snippet. For example, the user may supply a document title in one part of the snippet, and specify that the document title should be repeated in other places, with the first instance being all-uppercase and every other instance being lower-case.Snippet programming features
For applications that support scriptable snippets, the range of supported programming features varies. The following enumerates some of the features that are commonly implemented for programmable snippets.Plain text
Although plain text is a fundamental feature included even with applications that support only non-programmable "static" snippets, programmable snippets are also used for working with plain text.One common complication, however, is that environments that support programmable snippets often have to make distinctions between what counts as "plain text" and what counts as "programming instructions". Further complicating this distinction is the fact that applications that support programmable snippets almost always include support for recognition of multiple programming languages, either through basic syntax highlighting
Syntax highlighting
Syntax highlighting is a feature of some text editors that display text—especially source code—in different colors and fonts according to the category of terms. This feature eases writing in a structured language such as a programming language or a markup language as both structures and...
or execution of embedded commands.
For these and other reasons, emitting plain text from programmable snippets almost always entails being careful to avoid problems with syntax
Syntax of programming languages
In computer science, the syntax of a programming language is the set of rules that define the combinations of symbols that are considered to be correctly structured programs in that language. The syntax of a language defines its surface form...
and delimiter collisions.
Constants and variables
Programmable snippets often include an ability to establish a binding to an existing variable scope or namespace, from which the user can select any of various constants or variables. These might include values such as the email address of the currently-logged-in user on a given machine, the current system time and date, or the output value of a function.Scriptable snippets are often associated with one or more currently-active files. Consequently, variables may also include environment variables and arguments that specify the filename, cursor position, parent directory and other stats relating to the files in a current editing session.
Interpreted code
Scriptable snippets may allow execution of code in one or more programming languageProgramming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
s. This may include one or more standalone languages, or a language that is specific to the application in which the language is hosted.
See also
- AutocompleteAutocompleteAutocomplete is a feature provided by many web browsers, e-mail programs, search engine interfaces, source code editors, database query tools, word processors, and command line interpreters. Autocomplete involves the program predicting a word or phrase that the user wants to type in without the...
- CodebaseCodebaseThe term codebase, or code base, is used in software development to mean the whole collection of source code used to build a particular application or component. Typically, the codebase includes only human-written source code files, and not, e.g., source code files generated by other tools or...
- Integrated Development EnvironmentIntegrated development environmentAn integrated development environment is a software application that provides comprehensive facilities to computer programmers for software development...
- Macro (computer science)
- Design patternDesign patternA design pattern in architecture and computer science is a formal way of documenting a solution to a design problem in a particular field of expertise. The idea was introduced by the architect Christopher Alexander in the field of architecture and has been adapted for various other disciplines,...
- PastebinPastebinA pastebin is a type of web application that allows its users to upload snippets of text, usually samples of source code, for public viewing. It is very popular in IRC channels where pasting large amounts of text is considered bad etiquette. A new trend is that users use Pastebin to post Twitter...
- PreprocessorPreprocessorIn computer science, a preprocessor is a program that processes its input data to produce output that is used as input to another program. The output is said to be a preprocessed form of the input data, which is often used by some subsequent programs like compilers...
- Revision controlRevision controlRevision control, also known as version control and source control , is the management of changes to documents, programs, and other information stored as computer files. It is most commonly used in software development, where a team of people may change the same files...
- Web widgetWeb widgetIn computing a web widget is a software widget for the web. It's a small application that can be installed and executed within a web page by an end user. They are derived from the idea of code reuse. Other terms used to describe web widgets include: portlet, gadget, badge, module, webjit, capsule,...
- JITJITJIT may refer to:* Various meanings of Just In Time:** Just-in-time compilation - a technique for improving the performance of virtual machines in computing.** Just-in-time - a business inventory strategy.* Jabber ICQ Transport....
- Mail mergeMail mergeMail merge is a software function which allows to create multiple documents from a single template form and a structured data source.-History:This technique of merging data to create gave rise to the term mail merge....