.functions: Add `calc`

1 files changed, 18 insertions, 0 deletions

diff --git a/.functions b/.functions
index c2c1556..db887fa 100644
--- a/.functions
+++ b/.functions
@@ -1,3 +1,21 @@
+# Simple calculator
+function calc() {
+	local result=""
+	result="$(printf "scale=10;$*\n" | bc --mathlib | tr -d '\\\n')"
+	#                       └─ default (when `--mathlib` is used) is 20
+	#
+	if [[ "$result" == *.* ]]; then
+		# improve the output for decimal numbers
+		printf "$result" |
+		sed -e 's/^\./0./'        `# add "0" for cases like ".5"` \
+		    -e 's/^-\./-0./'      `# add "0" for cases like "-.5"`\
+		    -e 's/0*$//;s/\.$//'   # remove trailing zeros
+	else
+		printf "$result"
+	fi
+	printf "\n"
+}
+
 # Create a new directory and enter it
 function mkd() {
 	mkdir -p "$@" && cd "$@"