Emacs Lisp & Yasnippet
On my home machines as detailed in this post i keep a journal and used some fu to determine which machine the journal entry was written on. I also keep a daily log for work normally this consists of start time, mileage to be claimed so the snippet template resembles
text code snippet start
# -*- mode: snippet -*-
# name: daily
# key: daily
# --
** `(format-time-string "%Y-%m-%d-%H:%m" (current-time))`
:PROPERTIES:
:LOCATION:
:MILEAGE:
:START: `(format-time-string "%H:%M" (current-time))`
:FINISH:
:END:text code snippet end
At the start of everyday when i open up the laptop emacs is always there waiting and in the log for this year i type daily hit tab and voila my entry for the day commences
text code snippet start
** 2020-06-05-14:06
:PROPERTIES:
:LOCATION:
:MILEAGE:
:START: 14:06
:FINISH:
:END:text code snippet end
Location, mileage and end time are manually entered and normally i keep location as a set of abbreviations that match the mileage to claim this means using dynamic column view i can get a nice table of times/locations such as;
| ITEM | LOCATIONS | START | FINISH | MILEAGE | EXPENSE | TAGS |
|---|---|---|---|---|---|---|
| July 2018 | 745 | 207.03 | ||||
| 20180705 | 05:56 | 15:10 | 0.00 | :clock_anamoly: | ||
| 20180706 | 07:40 | 14:00 | 0.00 | |||
| 20180709 | MEA-WAR | 10:25 | 17:00 | 90 | 0.00 | :clock_anamoly:travel: |
| 20180710 | WAR | 07:40 | 17:00 | 0.00 | :travel: | |
| 20180711 | WAR | 07:40 | 17:00 | 3.30 | :travel: | |
| 20180712 | WAR-MEA | 07:40 | 13:30 | 90 | 48.45 | :travel:clock_anamoly: |
| 20180713 | MEA-TAM-MEA | 07:45 | 14:00 | 25 | 0.00 | |
| 20180716 | MEA-BHX-PARIS | 05:00 | 20:00 | 25 | 29.00 | :travel:clock_anamoly: |
| 20180717 | PARIS | 08:30 | 18:30 | 0.00 | :travel:clock_anamoly: | |
| 20180718 | PARIS-BHX-MEA | 08:30 | 00:00 | 25 | 0.00 | :travel:clock_anamoly: |
This then at the top of the file gets rendered into a smaller dynamic table so i can see cumulative mileage by month
| ITEM | LOCATIONS | START | FINISH | MILEAGE | TAGS |
|---|---|---|---|---|---|
| April 2018 | 400 | ||||
| May 2018 | 689 | ||||
| June 2018 | 682 | ||||
| July 2018 | 745 | ||||
| August 2018 | 155 |
now i’m working from home due to COVID i got tired of typing “home” everytime but i know there will be site & supplier visits coming up so i didnt want to alter the template and just add the text “home” so back to the point of this post which was to use a bit of emacs-lisp fu to get the snippet template to auto update location but how?
After a little thinking i came to the conclusion the easiest way would be to identify the network address the laptop is currently on, now admittedly this falls down if by some miracle everywhere i go has the same 192.168.1 start for IP address but i’ll test that when on the road. I started by reading up on network commands via
https://www.gnu.org/software/emacs/manual/html_node/elisp/Misc-Network.html
i then searched and found https://emacs.stackexchange.com/questions/7653/elisp-code-to-check-for-internet-connection and this was discussing auto updating packages if the connection was alive.
A bit of playing around i could see network-interface-list contained the info i wanted
elisp code snippet start
(print (network-interface-list))
#+RESULTS:
: ((lo0 . [127 0 0 1 0]) (lo0 . [0 0 0 0 0 0 0 1 0]) (eth1 . [169 254 195 98 0]) (eth1 . [65152 0 0 0 2226 39545 32787 50018 0]) (wlan2 . [169 254 127 144 0]) (wlan2 . [65152 0 0 0 20906 64385 58821 32656 0]) (wlan1 . [169 254 218 84 0]) (wlan1 . [65152 0 0 0 12504 37352 2860 55892 0]) (wlan0 . [169 254 231 54 0]) (wlan0 . [65152 0 0 0 41016 7035 59478 59190 0]) (eth0 . [192 168 1 14 0]) (eth0 . [65152 0 0 0 4387 56520 32424 30320 0]))elisp code snippet end
but then reading the first site also gave me network-interface-info so specifying the wireless network or in this case ethernet (i’m writing this on my main m\c) gives
elisp code snippet start
(print (network-interface-info "eth0"))
#+RESULTS:
: ([192 168 1 14 0] [192 168 1 255 0] [255 255 255 0 0] (1 . [244 77 48 24 93 135]) (dynamic running multicast broadcast up))elisp code snippet end
ok so i have the data what next? a little trial and error follows;
emacs-lisp code snippet start
(print (network-interface-info "wlan0"))
(setq x (nth 0 (network-interface-info "wlan0")))
(print x)
(format "%s" x)
(if (string-match-p "192 168 1" (format "%s" x))
"home"
"work")emacs-lisp code snippet end
there’s a lot wrong with the above and i’ve learned a bit more however given i start with zero emacs-lisp fu i think i can be spared a little leeway however it does ultimately work and can be pared down to the following;
emacs-lisp code snippet start
(if (string-match-p "192 168 1" (format "%s" (network-interface-info "wlan0")))
"home"
"work")emacs-lisp code snippet end
All that needs to happen now is for the code to be incorporated into the snippet;
text code snippet start
# -*- mode: snippet -*-
# name: daily
# key: daily
# --
** `(format-time-string "%Y-%m-%d-%H:%m" (current-time))`
:PROPERTIES:
`(if (string-match-p "192 168 1" (format "%s" (network-interface-info "wlan0")))
":LOCATION: HOME"
":LOCATION: ")`
:MILEAGE:
:START: `(format-time-string "%H:%M" (current-time))`
:FINISH:
:END:text code snippet end
Basically an hour of research and testing to save me what? 20s per day? thats going to be a long ROI before it pays off but i like learning and how knows what else may now be automated now that i have a little more fu.