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J by Example v2 Practical 4-page hands-on summary to give some idea how things are done in J. Formats: Text, HTML, PDF, PostScript and Vrabecz Attila created K by Example. Parallel of J and K are here in Text, HTML and PDF formats.

K. Smillie's J Companion for Statistical Calculations Means, medians and quartiles, frequency tabulations, variance, regression, plots, randomness, simulation, nonparametric tests, and probability distributions. Formats: PDF Letter, scripts.


sqlite 358 Kb v0.06 05-Oct-06
J bindings to SQLite embedded engine. Contains direct library calls as well as array-based economical bulk API. Includes Win32, Linux binaries; on Mac OS X it comes standard. SQLite Browser application views and queries database schema and data. See Phrase DB online service in JHP live demo. Summary and examples are here. For details see data/sqlite.
zip includes j504 191 Kb v0.06 23-Jul-06
Zip file utilities based on zlib 1.2.3 and minizip libraries. Interface API is similar to the files package. Includes Win32, Linux and Mac OS X universal binaries. For details see arc/zip.
xml includes j504 420.0 Kb v0.07 5-Aug-06
XML parser addon based on Expat 2.0.0 library. There is both flat API and object oriented, SAX-like interface. Binaries for Windows, Linux x86 and Darwin PPC included. For details and coding style see notes and examples and xml/sax.
JHP includes older j504 65.8 Kb v0.09 27-Sep-06
JHP: J Hypertext Processor. A J based engine to run server-side web applications and create dynamic web content. Syntax is similar to PHP or ASP. JHP can run on any platform and web server. Browse JHP to see it in action live on this server. The above link also contains documentation. Exciting dynamic OpenGL since v0.04, database v0.07 and other improvements. For details see web/jhp.
graphviz includes j504 1.30 Mb v0.03 22-Jul-06
Integrated with J, a popular graph drawing visualization library. Includes user interface Graph View and a utility to visualize sequential machines (finite automata). Contains reference and links. Screenshots available. See help.html for furter details. Run bin/install! See also companion cluster analysis (172 Kb) addon, featured on J Wiki.
jasync 27.1 Kb v0.01 21-Dec-05
Some study of multithreaded asynchronous execution in J. Supplied DLL is called from J and in turn calls a new instance of J engine on a separate thread of the same process. An arbitrary J script line is passed as a parameter. Contains examples of J engine non-reenterability.
pcre 256 Kb v0.01 5-Dec-04
Perl-compatible regular expression library. Proposed as replacement for current J regex DLL. For details see the source of the script. A performance comparison test with J regex is provided. Currently win32-only, but other platforms just require a different binary.


JayScript | view (53.1 Kb) v1.0.4 29-Jul-07
  J Language Active Script Connector. Implements Windows script interfaces. Allows J to be used as script for various scripting hosts: cscript/wscript shell with .ijss extension or a Windows Script File job, ASP, Internet Explorer; as well as custom applications that support scripting extensions. See more at J Wiki.
platimg platimg-0.07 | view (3.9 Kb) v0.07 22-Sep-06
  Platform neutral image reading and writing utilities with implementations for Windows, Linux and Mac OS X. Supports BMP, GIF, JPEG, PNG, TIFF, Exif, ICO, WMF, and EMF formats where available. Returns pixel matrix in ARGB (Alpha most significant) integer format. Expects ARGB, or triples of RGB in any axis of rank 3 array. Good for glpixels. Uses GDI+, Core Graphics (Quartz), The gdk-pixbuf Library from GTK+. See more at J Wiki.
animate (v0.01 for j501) (9.77 Kb) v0.05 27-Sep-06
  Generic extensible animation form suitable to host 2D or 3D graphics. Driven by timer the STEP parameter ranges from MIN to MAX. User code than each time builds the image for the current STEP, allowing both sequencial and random positioning. For examples see gl2test1.ijs and gl3test.ijs with such results. Plot, Isigraph, Viewmat packages and OpenGL give interesting animations. New j6 version produces image sequences convertible to movies.
okole j601 | j504 | j502 | j501 (19 Kb) v0.13 20-Jul-06
  Contains cover classes for use with particular ActiveX / OLE Automation components. NOTE: you need to have COMCTL32.OCX in %windows%\system32 properly licensed on your machine. Alternatively, MSCOMCTL.OCX may be used, but then you will have to correct the cc for TreeView/ListView/etc. in form creation accordingly.
Screen shots are available. (See for J 40x below)
split split.ijs | view j601+ (2.20 Kb)   15-Jul-06
  Splitter control for dynamically resizing boundary between two or more controls. Has a vertical and horizontal variety. Capable of having multiple splitters in one window. For details see J Wiki.
csvedit | view (6.65 Kb)   24-Jun-06
  CSV Editor is a utility application that allows to edit CSV files. There is a specific CSV file format convention for recognizing headers and treatment of quotes. For more information see J Wiki.
batchtest for j504+ 4.70 Kb updated 18-Mar-06
  Code-centric comparative batch tester. Operates on a number of cases (expressions of verbs that return the same result, but may differ in performance) and series (sets of input data for the cases). The result is tabulation, bar chart, plot and error log of each case against each series. Sample test: source, plot and table. See also J Wiki. Note: for j503 and below see source to modify.
plot3d plot3d.ijs | view (0.92 Kb)   16-Aug-05
  Plotting boolean 3-array, roughly equivalent to 3D version of viewmat. Also plots a list of 3-coordinates similarly. Here is an illustration.
transcode transcode.ijs | view (1.18 Kb)   20-Jan-05
  Simplistic transcoder which maps exact characters from search list to replacement list.
Example is an archaic Ukrainian DOS table to be upgraded to Windows code page.
jterm jterm.vbs | view, jexeterm.vbs | view 1.80 Kb   18-Sep-04
  VBScript terminal to run J console and EXE servers in DOS window command line mode. Also runs in any application has has built-in shell, e.g. Emacs
Requires Windows Scripting Host and VBScript (
This script file needs to be run in console (not window) mode, i.e by cscript.exe rather than wscript.exe. NOTE: this gives a generic example of using J Automation server from windows scripts. Screen shot is available.
ado ado.ijs | view 3.06 Kb v0.03 28-Mar-04
  Module for date access with ADO. Requires MDAC 2.6 or above. Output formatted into boxed cells or columns. Field names can be retrieved. Numerics can be converted. Contains verbs that can be easily used in expressions to select connection string and perform SQL operations. Can be similarly extended to include transations, cursor types, etc.
viewfld viewfld.ijs | view      old | view (30-Dec-03) 2.48 Kb 11-Mar-04
  View Field, an extension to viewmat for complex values. Screenshots (much nicer after j503cbeta): cos, jiota, log, Lotka-Volterra. Updated version is rewritten in mostly complex bulk operations and has improved documentation.
xsl xsl.ijs | view 2.55 Kb 24-Nov-03
  XSL Transformation of a text XML with a text XSLT. Useful for obtaining a flat text for further processing with J. Requires MSXSL v4.
The idea is to avoid reinventing the wheel trying to make XML parser in J, but use world's best XML tool for what it does best and leave flat structures to the world's best rectangular data tool.
flattoolbar tbtest.ijs | view 1.67 Kb 12-Nov-03
  Flat Toolbar. Win32 feature to change the appearance of a toolbar to get the flat look. Works on J Forms with a toolbar. See a screenshot.
map map.ijs | view (5.74 Kb) v0.02 23-Oct-03
  map -- Map of (,:key;value) pairs. A set of functions, similar to existing dictionary object, but in contrast maps allow to operate plain boxed J arrays, thus no locales are used and no effort is need for for import/export. Generally good for small to medium data volumes, but having semantical and structural richness. Possible applications: (1) metadata, as in detailed header for keyfiles stored in extra for each item and describing the item's structure; (2) GUI, graphics or document elements, which can be manipulated as in DOM and later transformed to other format, e.g. wd'', glXXX, etc. (3) an equivalent or representation of XML data structures. Now with multiline string and compact multikey-per-line representations, good for configs and declarative programming.
task task.ijs | view (7.1 Kb)   19-Oct-03
  Verbs to allow running tasks with enhanced features: fork (usually windowed) tasks with optional timeout or no waiting, spawn (mostly command-line) tasks sending input and capturing output, shell spawing shell commands with I/O. No temporary files!
md5 wincrypt.ijs | view      crypt.ijs | view (1.88/3.07 Kb)   4-Sep-03
  wincrypt -- Windows API cryptography. See MSDN for details
crypt -- RSA Data Security, Inc. MD5 Message-Digest Algorithm. See RFC 1321 for license details
timer timer.ijs | view (5.08 Kb) alpha 27-May-03
  Universal timer singleton registering and triggering events: both recurrent (time span in msec) and one-time scheduled (absolute time). Features realtime-like concurrency, synchronization, setting/killing/modifying events; priority setting/reseting, number of times to run or forever; info for a single event and state report for all events. To-do -- fix a bug with tight new span; try/catch; system hook for tracing, etc.
Screenshot 1, Screenshot 2 are available.
dynplot dynplot.ijs | view (1.7 Kb)   20-May-03
  Multiwindow independent animations. Uses a timer singleton object to handle multiple independent timers.
Screen shot is available.
borderless borderless.ijs · view | borderless-j5.ijs · view (4.1 Kb)   2-Aug-06
  Represent a standard J Form as a borderless window of arbitrary shape, the area outside of the shape being transparent.
Screen shot is available.
okhtml2 (0.8 Kb)   5-Mar-03
  Converts J boxed output to HTML table. Updated for J 50x.
Available are charset sample and embeded boxes sampler. (See for J 40x below)
plotpdf (4 Kb)   9-Dec-02
  PDF Formatter for J Plot. Compatible with j406, j406 ce, j501, j501 ce.
Screen shots are available. (See plotpdf.ijs source code.)
jgl2vml jgl2vml.html 8.57 Kb 7-Jan-01
  J Plot VML is based on intercepting gl2 commands to generate VML graphs and charts. Allows to bring the power of J and its graphical engine to the Web and HTML applications. Serves as a prototype for client and server-side solutions.
To see the demo, you need Windows machine with MS Internet Explorer having VML and XML support, plus J v4.0x installed on your machine. Tested on IE v5.5 and 6.0. As J is called as ActiveX, security settings need to be adjusted.
NOTES: J part is fairly well optimized, however numerous reloads of page result in "out of memory": close page and open a fresh one. VML part suffers at plots with multiple polygons, like WIRES and SURFACES. Currently awkward way to allow textr and textc alignment result in slower updates.
j62ipaq j62ipaq.exe 198 Kb (203,264 b) v0.04 14-Dec-00
  Built from J6.2 distribution source, for Windows CE 3.0 device with StrongArm 1100 processor, e.g. tested on PocketPC iPaq 3600. To install, copy this .exe to the device, don't run it on a PC. To run, requires console.dll 33.5 Kb (34,404 b) (from MS Platform Builder 3.0) placed to /windows folder. IMPORTANT: Verify the file sizes after both download and copying to the device. Recommended are the installation notes. Screen shots are available. NOTE: some features are cut off, due to limitation of C runtime for CE. E.g. the ts xeno. All copyright and licensed material is subject to respective agreements. Alternative is a bulk 197 Kb (202,262 b), including it all.
sdoc2htm (4.7 Kb) v2.00 5-Dec-00
  Produces HTML/CHM from scriptdoc. This tiny SOB generates over 400k worth of HTML help for J system scripts. Sample file for J4.05x: sdoc.chm (84 Kb) - can either Save or Open right from here. Generated set of HTML files: (cf J4.03: sdoc101.chm,, and J4.02:,
regexs (earlier (2.3 Kb) v2.00 6-Oct-99
  Regular expressions extended for Perl/awk/sed-like substitution. Features an option to process executable replacements. Also see regexs2 source (earlier regexs), examples and the idea. Recommended is the new version 2 based on Chris Burke's new rplc being also included.
testjava (0.7 Kb)   22-Aug-99
  Demonstrates using Java classes registered as COM in J
Requires Microsoft Java SDK or MS Visual Studio 6.0
console (10.1 Kb)   8-Aug-99
  Windows Console functionality
sqlview (14.9 Kb) v0.01 6-Jul-99
  Simple ODBC SQL query viewer
okole (21 Kb) v0.02 4-Jul-99
  Contains cover classes for use with particular ActiveX / OLE Automation controls.
Screen shots are available. (Earlier
menu (1.9 Kb) v0.02 24-Dec-98
  Win32api popup menu
okhtml (0.8 Kb)   19-Oct-98
  Converts J boxed output to HTML table.
Available are charset sample and embeded boxes sampler.
clipbrd (3.4 Kb)   7-Dec-98
  Provides an interface to Win32api clipboard functionality
grdata | (for j4xx) (15.0 Kb) v1.02 28-Oct-03
  Suited for displaying the results of J expresions in a grid. Custom implementation in low-level grid API.
Screen shots are available. Also see help text.


SAXPSA | (original) (104 Kb) 13-Mar-07
  Sharp APL Type 1 Font. Originally created by Joey Tuttle with various contributions and configurations by other authors. See readme for more details, history and easy installation instructions. Rendering with Acrobat Reader 8.0.
OKFonts (12.2 Kb) v1.01 20-Aug-99
  Windows OEM and ANSI fonts for use in J. Code pages 866, 1251. Screen shots are available.
sliderule view 05-Sep-19
  Circular slide rule in Canvas. Original similar slide rule is done in VML by Andrew Nikitin: KL-1 Emulator.
Valid HTML 4.0!