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Emacs mode for editing q scripts and communicating with inferior q/qcon buffers
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q-mode is a major mode for editing q (the language written by Kx Systems) in Emacs.

Some of its major features include:

  • syntax highlighting (font lock),
  • interaction with inferior q[con] instance,
  • scans declarations and places them in a menu.


To load q-mode on-demand, instead of at startup, add this to your initialization file

(autoload 'q-mode "q-mode")

The add the following to your initialization file to open all .k and .q files with q-mode as major mode automatically:

(add-to-list 'auto-mode-alist '("\\.[kq]\\'" . q-mode))

If you load ess-mode, it will attempt to associate the .q extension with S-mode. To stop this, add the following lines to your initialization file.

(defun remove-ess-q-extn ()
 (when (assoc "\\.[qsS]\\'" auto-mode-alist)
  (setq auto-mode-alist
        (remassoc "\\.[qsS]\\'" auto-mode-alist))))
(add-hook 'ess-mode-hook 'remove-ess-q-extn)
(add-hook 'inferior-ess-mode-hook 'remove-ess-q-extn)


Use M-x q to start an inferior q shell. Or use M-x q-qcon to create an inferior qcon shell to communicate with an existing q process. Both can be prefixed with the universal-argument C-u to customize the arguments used to start the processes.

The first q[con] session opened becomes the activated buffer. To open a new session and send code to the new buffer, it must be actived. Switch to the desired buffer and type C-c M-RET to activate it.

Displaying tables with many columns will wrap around the buffer - making the data hard to read. You can use the toggle-truncate-lines function to prevent the wrapping. You can then scroll left and right in the buffer to see all the columns.

The following commands are available to interact with an inferior q[con] process/buffer. C-c C-l sends a single line, C-c C-f sends the surrounding function, C-c C-r sends the selected region and C-c C-b sends the whole buffer. If the source file exists on the same machine as the q process, C-c M-l can be used to load the file associated with the active buffer.


M-x customize-group can be used to customize the q group. Specifically, the q-program and q-qcon-program variables can be changed depending on your environment.

Q-mode indents each level based on q-indent-step. To indent code based on {}-, ()-, and []-groups instead of equal width tabs, you can set this value to nil.

The variables q-msg-prefix and q-msg-postfix can be customized to prefix and postfix every msg sent to the inferior q[con] process. This can be used to change directories before evaluating definitions within the q process and then changing back to the root directory. To make the variables change values depending on which file they are sent from, values can be defined in a single line a the top of each .q file:

/ -*- q-msg-prefix: "system \"d .jnp\";"; q-msg-postfix: ";system \"d .\"";-*-

or at the end:

/ Local Variables:
/ q-msg-prefix: "system \"d .jnp\";"
/ q-msg-postfix: ";system \"d .\""
/ End:
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