Editing Code folding (section)

{{Short description|Tool of editors for programming, scripting and markup}}
{{confuse|Constant folding}}
[[File:Vim-folding.png|thumb|upright=1.35|Code folding example on [[PHP]] code with [[vim (text editor)|Vim]]]]
'''Code''' or '''text folding''', or less commonly '''holophrasting''',<ref>Simon Gauvin, Omid Banyasad, "Transparency, holophrasting, and automatic layout applied to control structures for visual dataflow programming languages", in ''Proceedings of the 2006 ACM symposium on Software visualization'', p. 67–75</ref> is a feature of some [[graphical user interfaces]] that allows the user to selectively hide ("fold") or display ("unfold") parts of a document. This allows the user to manage large amounts of text while viewing only those subsections that are currently of interest. It is typically used with documents which have a natural [[tree structure]] consisting of nested elements. Other names for these features include '''expand and collapse''', '''code hiding''', and '''outlining'''. In [[Microsoft Word]], the feature is called "collapsible outlining".

Many user interfaces provide [[disclosure widget]]s for code folding in a sidebar, indicated for example by a triangle that points sideways (if collapsed) or down (if expanded), or by a <code>[-]</code> box for collapsible (expanded) text, and a <code>[+]</code> box for expandable (collapsed) text.

'''Code folding''' is found in [[text editor]]s, [[source code editor]]s, and [[integrated development environment|IDE]]s. The folding structure typically follows the [[Abstract syntax tree|syntax tree]] of the program defined by the [[computer language]]. It may also be defined by levels of [[Indentation style|indentation]], or be specified explicitly using an in-band marker (saved as part of the source code) or out-of-band.

'''Text folding''' is a similar feature used on ordinary text, where the nested elements consist of paragraphs, sections, or [[Outline (list)|outline levels]]. Programs offering this include [[folding editor]]s, [[outliner]]s, and some [[word processor]]s.

'''Data folding''' is found in some [[hex editor]]s and is used to structure a binary file or hide inaccessible data sections.<ref>{{cite web |title=HxD - Freeware Hex Editor and Disk Editor |website=mh-nexus |url=http://mh-nexus.de/hxd/ |accessdate=2007-04-30}}</ref> 

Folding is also frequently used in [[data comparison]], to select one version or another, or only the differences.