From 50142a0aec3e5dfd604187551a7921346ba38300 Mon Sep 17 00:00:00 2001
From: Simon Michael <simon@joyful.com>
Date: Thu, 2 Dec 2021 10:54:23 -1000
Subject: [PATCH] bin: hledger-number

---
 bin/hledger-number.sh | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100755 bin/hledger-number.sh

diff --git a/bin/hledger-number.sh b/bin/hledger-number.sh
new file mode 100755
index 000000000..54037a4c8
--- /dev/null
+++ b/bin/hledger-number.sh
@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+# hledger-number - try to extract just one single machine-readable number from hledger:
+# the grand total of `hledger balance` run with any provided arguments.
+# Requires hledger 1.24 or newer (the December 2021 release, see https://hledger.org/download.html )
+# https://gist.github.com/simonmichael/feee7fc1567c5f10355f952b87bd3090
+
+VALUATION_COMMODITY="$"
+hledger bal -0 -N -X "$VALUATION_COMMODITY" --infer-market-prices -c "$VALUATION_COMMODITY 1000" --layout=bare "$@" | awk '{print $1}'
+
+# Tired of complex financial reports ? This is a silly but fun and
+# occasionally useful script showing how to get "one number" semi-robustly
+# without writing a haskell script. With this installed in PATH, then eg:
+#
+# $ hledger number lodging
+# 200
+#
+# Explanation:
+# -0 (--depth 0) hides all but top-level accounts
+# -N (--no-total) hides the totals line
+# -X COMM (--value=end,COMM) converts to a single commodity if possible (needs at least one suitable P market price declaration) 
+# --infer-market-prices guesses P price from conversion transactions if necessary
+# -c (--commodity-style) sets a predictable number format free of thousands separators
+# --layout=bare moves the commodity symbol away from the number
+# awk discards all but the number
+#
+# A note: If you're new to hledger/PTA and thinking it shouldn't be this hard..
+# well of course normally when a hledger user wants to see one number, they run
+# a much simpler command like `hledger bal lodging` or `hledger reg lodging`.
+# This script is exploring how to anticipate and neutralise all variations
+# caused by account structure, number formatting, mulltiple commodities, etc.
+# so as to *reliably* produce *one machine readable number* from highly diverse
+# data. As we figure out good approaches we'll build them in so that eg
+# producing data for charting is as easy as it can be, while still being
+# general.