Most text editors support syntax coloring and since J only has a very small number of syntactic classes, it is very easy to write a specification file for J. Utilities for syntax coloring (aka syntax highlighting) are also becoming more common for displaying code on HTML pages.
Here are some examples of syntax specification files.
Note that some editors support theme so that actual screenshots should be different from what are displayed here.
This required Vim version 7.0 or above.
If the directory $HOME/.vim/syntax does not exist, create it by typing inside terminal
mkdir -p ~/.vim/syntax
Create or edit the file filetype.vim inside your $HOME/.vim directory, as follows.
" my filetype file if exists("did_load_filetypes") finish endif augroup filetypedetect au! BufRead,BufNewFile *.ijs,*.ijt,*.ijp,*.ijx setfiletype j augroup END
Copy the file File:J.vim.txt (and rename to j.vim) to your $HOME/.vim/syntax directory.
The name of directory .vim for ms window is vimfiles and $HOME can be found be typing :echo $HOME.
Screenshot: The actual color displayed depends on current color scheme. There are many color schemes inside vim's wikia site. Vim scripts Vim scripts - Vim Tips Wiki - a Wikia wiki
console vim 7.2 using desert256 color scheme on xterm-256 color
gtk+ gvim 7.2 using fruidle color scheme on Ubuntu
j-mode edit and run J code with Emacs
Copy the file File:J.syntax.txt (and rename to j.syntax) to your $HOME/.mc/cedit directory.
Enter menu "Command -> Edit syntax file" and insert following lines:
file ..\*\\.ij[xs]$ J\sFile include $HOME/.mc/cedit/j.syntax
mc 4.6.2-pre1 on xterm
The Guides/Syntax Coloring/GeSHi Options page describes some decisions regarding J syntax highlighting in GeSHi that need to be made. Please register your views there or on the forum.
Copy the file File:J.xml.txt (and rename to j.xml) to your $HOME/.kde4/share/apps/katepart/syntax directory. Restart Kate editor. Open ijs file or switch to window with J script. Select menu item "Tools -> Highlighting -> Scripts -> J".
Kate 3.7.2 using KDE 4.7.2 on openSUSE 12.1
Kate with folding
Copy the file File:J13.xml.txt (and rename to j.xml) to your $HOME/.kde4/share/apps/katepart/syntax directory. Restart Kate editor. Open ijs file or switch to window with J script. Select menu item "Tools -> Highlighting -> Scripts -> J".
Folding for indentations and for multiline definitions
starting with: ":\s*0", "define" or "NB.("
and ending with "NB.)" or ")" <on a line alone>
Copy the file File:J.hrc.txt (and rename to j.hrc) to "C:\Program Files\Far Manager\Plugins\FarColorer\base\hrc\auto\types" directory. Insert following lines:
<prototype name="j" group="main" description="J"> <location link="types/j.hrc"/> <filename>/\.ij[sxl]$/i</filename> </prototype>
into "C:\Program Files\Far Manager\Plugins\FarColorer\base\hrc\auto\empty.hrc" file somewhere between "</annotation>" and "</hrc>". Restart Far Manager. Open ijs file for edit.
Far Manager 3.0 on Windows 7
Sublime Text 3
Support for syntax coloring and comment toggling is available for the cross-platform editor Sublime Text from the following Github repository. Note that the TextMate grammar file `J.tmLanguage` in this repository is used by GitHub to highlight J code on their site.
Visual Studio Code
Support for syntax coloring and comment toggling is available for the free, open-source, cross-platform editor VS Code in the form of the J extension published on the Visual Studio Marketplace. The source is maintained at the following Github repository
- vim vim online