Snippet (programming)

Snippets can be classified according to the interactivity in using it, including: ;Static: A static snippet is fixed text that can be inserted without entering information at insertion-time. ;Dynamic: A dynamic snippet contains placeholders for which the user may be required to enter replacement text at insertion-time. ;Scriptable: A scriptable snippet is runnable code. Support for such snippets may include running a shell command, 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. ==Placeholder==

A placeholder is a part of a snippet that is replaced at insertion-time. Generally, a placeholder has special markup syntax that allows the development tool to identify the boundaries of each placeholder so that it can replace it. Some tools provide a graphical user interface (GUI) in which the user can replacement values. A placeholder is usually delimited in a snippet with special syntax and may be identified by a name or a number. The following snippet text uses identified placeholders: first_name, last_name, and item: Hello {%first_name%} {%last_name%}, Your shipment of {%item%} is now ready to pick up. Thanks {%first_name%}! With an identified placeholder, a snippet can use the same replacement value multiple times. In the previous example, the placeholder first_name is an example of this use. Transformation 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. == Example ==

The algorithm of swapping the value of two variables, and could be coded as: temp = x x = y y = temp To make the snippet more useful, the variable names are replaced with placeholders as: temp = $1 $1 = $2 $2 = temp When the snippet is inserted, the development tool might prompt the developer for more specific names to replace the placeholder names. For and , the inserted code is: temp = foo foo = bar bar = temp If the snippet is subsequently changed, say to use __temp instead of temp, the existing code would not automatically use the new snippet definition, but subsequent insertions would. ==Alternatives==

A common alternative to snippet use is the function which has the advantage that modifying its definition affects consumers whereas modifying a snippet does not modify existing insertions of the snippet. Many development techniques such as object-oriented programming and functional programming stress the avoidance of duplicate code which is counter to using snippets. Another alternative is the preprocessor macro which is available in C and many related languages. ==Related==

; Design pattern: A design pattern is similar to a snippet in that code is generated rather than coded as functions, but a pattern differs in scope. A pattern is relatively large while also is challenging to code as a reusable library. ; Object code fragment: Similar to a source code snippet, a just-in-time (JIT) compiler can splice together pre-compiled code as longer object code segments. This reduces interpret time and speeds execution. ; AI code insertion: Generative artificial intelligence (AI) such as GitHub Copilot can infer functionality from source code and insert relevant code that one might consider similar to a snippet. == See also ==