File: more-examples.sh
   1 #!/bin/sh
   2 
   3 # more-examples.sh
   4 #
   5 # Here are several command-line examples using `gt` (short for `gotron`,
   6 # which in turn is short for `GO TRansform jsON`).
   7 #
   8 # All commands should run on a linux-style shell as they are: you can even
   9 # run this file as a shell script, if all goes well.
  10 
  11 
  12 case "$1" in
  13     -h|--h|-help|--help)
  14         awk '/^# +examples\.sh/, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  15         exit 0
  16     ;;
  17 esac
  18 
  19 
  20 # find out how long 4GB last when playing 16-bit PCM sounds for various
  21 # settings; results then turned from seconds into HH:MM:SS-style strings
  22 gt '// 16-bit/2-byte samples, mono or stereo, for both CD-audio and DAT
  23     _{44_100, 48_000} * _{mono: 1, stereo: 2} * 2 &
  24 
  25     // find how many seconds 4 GB last with those settings, playback-wise
  26     (4 * gb) / _ &
  27 
  28     // turn seconds into HH:MM:SS.SS-style strings
  29     _ . dive(a(floor(v / 3600), floor(v % 3600 / 60), fix(v % 60, 2)) ^ `:`)
  30 ' .
  31 
  32 # get recent `live` exchange rates from the bank of canada, transforming
  33 # values from the latest record; the trick at the end of the URI is to
  34 # limit data-transfer size, by asking for records only for the current year
  35 gt 'define(
  36         latest, _.observations[-1],
  37         rates, latest.drop(`d`),
  38     ) &
  39 
  40     // improve keys/names by removing everything around the 3-letter
  41     // currency codes, then pick `v` fields, parsing them into numbers
  42     rates . each(k - `FX` - `CAD`, +v.v | v) &
  43 
  44     // rename field `d` as `date`, and use all entries from the previous
  45     // step, sorted by their currency-code labels
  46     merge(_{ date: latest.d }, _.sort(k))
  47 ' https://www.bankofcanada.ca/valet/observations/group/FX_RATES_DAILY/json?start_date=`date +%Y`-01-01