Emacs (Chart Manual)

18 Emacs

http://www.gnu.org/software/emacs/

chartprog.el shows the Chart watchlist and gets quotes within Emacs (see The Emacs Editor in The Emacs Editor). It’s designed for Emacs 21 and higher, and also works with XEmacs 21 if you have the UTF-8 coding system (see below).

The Debian package has the following setups already. Otherwise, the best way to use chartprog.el is with autoloads for the commands. chartprog-loaddefs.el is a small file which sets this up. Add the following to your .emacs file (see The Init File ~/.emacs in The Emacs Editor),

(require 'chartprog-loaddefs)

The build system currently doesn’t install chartprog.el into site-lisp, so you should copy it and chartprog-loaddefs.el to somewhere in your load-path (see Libraries of Lisp Code for Emacs in The Emacs Editor).

18.1 Watchlist and Quotes

M-x chart-watchlist displays the Favourites list in a buffer. Key a adds a symbol. C-k and C-y kill and yank symbols. g refreshes the quotes. L selects a different list (like the Alerts list). The usual C-h m mode help shows other key bindings.

Chart communicates changes to the lists between the Emacs display and a running Chart GUI. So if you have both open then changes in one are reflected in the other a moment later.

M-x chart-quote displays a quote for a given symbol in the message area. It prompts for the symbol with default a symbol at point. Tab completion is available (see Completion in The Emacs Editor) using the database symbols, favourites list, and previously requested symbols.

M-x chart-quote-at-point displays a quote for the symbol at point, without prompting.

The language, date formats, etc, follow the Chart locale selection described in Internationalization. Emacs M-x set-language-environment and other Emacs setups don’t influence the display.

18.2 UTF-8

UTF-8 is used in Emacs, the same as in the Gtk GUI display. This is easiest to implement, and should mean whatever is seen in the GUI can be seen in Emacs.

Emacs 21: If you use an Asian locale then you probably know Emacs 21 has limited support for Asian parts of UTF-8. The typical symptom is ‘\207’, ‘\221’ etc in the display. Install the MULE-UCS package to add to the builtin characters: http://www.m17n.org
XEmacs 21: If you use XEmacs 21 you probably know it has no builtin UTF-8. To run chartprog.el you must get one of the add-ons providing that. MULE-UCS is recommended (http://www.m17n.org), and chartprog.el will attempt to load it automatically.

18.3 Lisp

Function: chart-latest symbol &optional field scale

Return the latest price for symbol (a string) from Chart. If there’s no information available (an unknown stock, not online, nothing cached, etc) the return is nil.

(chart-latest "F") ⇒ 19.55

field is a lisp symbol for what data to return. The default is last which is the last traded price. The fields are

name                        string or nil
bid offer                   \ prices or nil
open high low last change   /
quote-date last-date        string like "2012-12-31", or nil
quote-time last-time        string like "16:59:59", or nil
volume                      number or nil
note                        string or nil

Which fields actually have data depends on the data source. name is the stock or commodity name as a string, or nil if not available. Dates and times are in the timezone of the symbol. note is a string with extra notes, such as ex-dividend or limit up, or nil if no other notes.

(chart-latest "F" 'volume) ⇒ 10492900

scale (an integer) is how many places to move the decimal point down. For example if SCALE is 2 then price 1.23 is returned as 123. This is good for working in cents when quotes are in dollars, etc.

chart-latest doesn’t download new quotes but just returns existing data.

Form: thing-at-point 'chart-symbol: A call (thing-at-point 'chart-symbol) gives the Chart symbol at point (see Examining Buffer Contents in GNU Emacs Lisp Reference Manual). Note that you must (require 'chartprog) before using this, it’s not autoloaded.

18.4 Simple Emacs Spreadsheet

chart-latest above can be used in SES (see Simple Emacs Spreadsheet in Simple Emacs Spreadsheet) expressions to include prices in a portfolio etc. See emacs/example.ses in the Chart sources for a sample spreadsheet doing this.

Since chart-latest doesn’t download new data an M-x ses-recalculate-all just shows existing downloaded quotes (see Cell formulas in SES: Simple Emacs Spreadsheet).

M-x chart-ses-refresh does a combination ses-recalculate-all and download of Chart prices used. A first recalculate records calls to chart-latest for which prices are used in the spreadsheet, they’re downloaded, then a second recalculate applies the new data. (Further rounds of download and recalculate are done as necessary if conditionals in expressions use yet more symbols.)

Chart is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.