Regular Expression Development


Execution Tool

Redet in operation


  1. Overview
  2. News
  3. Programs Supported
  4. Comparison With Other Regular Expression Tools
  5. Platforms
  6. Details
  7. Documentation
  8. Reviews
  10. Roadmap
  11. Known Bugs
  12. Change Log


Redet (Regular Expression Development and Execution Tool) facilitates the construction and testing of regular expressions using any of a variety of search programs, editors, and programming languages that make use of regular expressions. When a suitable regular expression has been constructed it may be saved to a file. Redet is useful both for constructing regular expressions for use elsewhere and as a search and replacement environment in its own right.

For each program, a palette showing the available regular expression syntax is provided. Selections from the palette may be copied to the regular expression window with a mouse click. Users may add their own definitions to the palette via their initialization file. Redet also keeps a list of the regular expressions executed, from which entries may be copied back into the regular expression under construction. The history list is saved to a file and restored on startup, so it persists across sessions. So long as the underlying program supports Unicode, redet allows UTF-8 Unicode in both test data and regular expressions.

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Version 8.26 fixes several bugs having to do with initialization files. The palette window now responds properly to resizing.

Programs Supported

The programs currently supported are:

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Comparison With Other Regular Expression Tools

Redet is but one of a number of tools that provide assistance in using regular expressions with different capabilities and purposes. Which one should you choose?

Here are some of Redet's distinctive properties:

Even I don't think that Redet is the best tool for all purposes. For one thing, it assumes that the user knows something about regular expressions or is willing to spend some time learning. The novice who doesn't want to learn more or doesn't have time to should try txt2regex which walks the user through the construction of the regular expression and generates output for 20 different programs and languages. It is one of the few tools that isn't specialized for a particular language or program. Another tool helpful to novices is Kregexpeditor, which is part of the KDE package. Kregexpeditor is a graphical tool that works rather like a diagram editor. It generates regular expressions using either the syntax of the Qt windowing toolkit or the Emacs editor.

Some programs provide details about the matching process. regex-coach, for example, can single-step through the match and show the parse tree, so it is useful if you want to understand the matching process in detail. It uses PERL-style regular expressions. Regexpviewer and Visual REGEXP will show you which portions of the text were matched by which group in the regular expression. Both use Tcl regular expressions. Kiki and Kodos are similar, rather more elaborate, tools for Python. Programs like Redet that support many different regular expression matchers cannot provide this kind of detail because they don't execute the regular expressions themselves.

Some programs provide insight into the relationship between regular expressions and finite state automata and into the implementation of regular expression engines. re_graph draws the finite state automaton corresponding to a given regular expression and annotates the diagram in such a way as to show the correspondance between parts of the regular expression and parts of the automaton. qfsm is a graphical tool for designing finite state automata directly.

A more extensive list of regular expression and pattern matching software can be found here.

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Due to the wide availability of Tcl/Tk, there is a good chance of getting redet to work on most platforms. Use of facilities known to be operating system-specific has been avoided. It is developed and tested most extensively under GNU/Linux. Platforms on which Redet is known to run are:

There are two implementations of Tk for Mac OS X: Tk-X11 and Tk-Aqua. Redet runs properly with Tk-X11 (for which, naturally, you must have X11 installed). It now also adapts itelf to Tk-Aqua, the native Mac OS X implementation of Tk. It is usable with Tk-Aqua but some details still require work.

Native Macintosh executables of Tcl/Tk that run under Aqua may be obtained from

If you attempt to install redet on another system, I would appreciate learning whether you were successful and if problems were encountered, what they were and how you resolved them, if you did.

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Dependencies (strong)Tcl/Tk version 8.3 or higher
Current version8.26
Last modified2008-09-11
LicenseGNU General Public License version 3
ContactBill Poser

Note: obtaining the necessary Tcl/Tk environment.

The GUI requires both the basic Tcl/Tk distribution and the iwidgets library. If you already have Tcl/Tk and just need to add iwidgets, you can obtain the package from the Sourceforge project site. On the download page you will find source and binary packages for both [incr Tcl/Tk], which is the basic part of this package, and [incr widgets], which is the part that contains the widgets. You will need to install both. (iwidgets is an alternative name for [incr widgets].)

The easiest way to obtain the Tcl/Tk environment you need is to install the ActiveTcl distribution from ActiveState. This distribution provides the Tcl language, the Tk graphics library, and a bunch of extensions, including [incr tcl] and [incr widgets]. Don't be concerned by the fact that ActiveState is a commercial outfit. The Tcl/Tk distribution that they provide is free as in both beer and speech. They make their money selling services and programming tools. The ActiveTcl distribution is currently available for: GNU/Linux, HP-UX, AIX, Solaris, Mac OS X, and MS Windows.

For FreeBSD, Tcl and Tk are available at:

FreeBSD has a different convention for naming the Tcl executables, which the Makefile supplied here does not account for. The FreeBSD Redet Freshport takes care of this.

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Read the reference manual (numerous screenshots)


(Although Linux Magazin is in name the German counterpart of Linux Magazine the articles are not mere translations of each other.)

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Note that the program and the reference manual are now packaged separately. Since the reference manual (≅5MB) is much larger than the program (≅300KB) and does not change as often you may find that you only want to download the program itself. (For the program the bz2 compressed file is smallest, but for the manual the gzipped file is the smallest.)

If you would like to be notified of new releases, subscribe to Redet at Freshmeat.

A variety of packages are available:

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Known Bugs

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Change Log





Full Change Log
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