Folding editor

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An example of text folding within Vim. The list in the text is shown folded (above the black bar) and unfolded (below the black bar).

A folding editor is a text editor which supports text folding or code folding, a mechanism allowing the user to hide and reveal blocks of text—usually named. Typically this is done to allow the user to better picture the overall structure of a document or program.

Folding is provided by many modern text editors, and syntax-based or semantics-based folding is now a component of many software development environments.


One of the earliest folding editors was STET, an editor written for the VM/CMS operating system in 1977 by Mike Cowlishaw. STET is a text editor (for documentation, programs, etc.) which folds files on the basis of blocks of lines; any block of lines can be folded and replaced by a name line (which in turn can be part of a block which itself can then be folded).

A folding editor appeared in the occam IDE circa 1983, which was called the Inmos Transputer Development System (TDS).[citation needed]. The "f" editor (in list below) probably is the most intact legacy from this work.

The Macintosh computer historically had a number of source code editors that "folded" portions of code via "disclosure triangles". The UserLand Software product Frontier is a scripting environment that has this capability.[1]

Editors with folding capability[edit]

A number of text editors provide folding capability. Those that do include:

See also[edit]


  1. ^ "". Retrieved 2006-12-27. 
  2. ^ LEXX – A programmable structured editor IBM Journal of Research and Development, Vol 31, No. 1, 1987, IBM Reprint order number G322-0151

External links[edit]