custom-shell-scripts/decimal_compare at main · jmortiger/custom-shell-scripts · GitHub

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#!/usr/bin/env bash

# declare -r MY_PATH="$0"
readonly MY_PATH=$(realpath "$0")
MY_NAME=''
if [[ "$MY_PATH" =~ ^(.*)/([^/]+)$ ]]; then
	readonly MY_NAME="${BASH_REMATCH[2]}"
else
	readonly MY_NAME="$0"
fi
readonly MATCH_LINE='^[[:blank:]]*exit_error .*?'
exit_error() {
	if [[ "$1" =~ ^[[:digit:]]+$ ]]; then local -ir errorCode=$1; shift; else local -ir errorCode=1; fi
	line=$(grep -m 1 -n -E -e "$MATCH_LINE($1)" "$MY_PATH")
	if [[ "$line" =~ ^([[:digit:]]+) ]]; then
		line="${BASH_REMATCH[1]}: "
	else
		line=''
	fi
	echo "$MY_NAME: $line$*" 1>&2
	exit $errorCode
}
show_help() {
	cat << __EOF__
Perform the given comparison operation.

Usage:	$0 LHS OPERATOR RHS
	or:	$0 --help
	or:	$0 --version

Options:
	-h, --help: Shows this help text.
	-v, --version: Shows version info.
__EOF__
}
show_version() {
	cat << __EOF__
$0 1.0.0

Copyright (C) 2025 Justin Morris
__EOF__
}

shopt -s 'extglob'
allowContinue='true'
while eval "$allowContinue" && (( $# > 0 )); do
	case "$1" in
		(-h | --help)
			show_help
			exit
			;;
		(-v | --version)
			show_version
			exit
			;;
		(*)
			allowContinue='false'
			;;
	esac
done

declare -i sign1=0
declare -i whole1=0
declare -i frac1=0
if [[ "$1" =~ ^(-?)([[:digit:]]+)\.([[:digit:]]*)$ ]]; then
	((sign1 = ${#BASH_REMATCH[1]} > 0 ? -1 : 1, whole1 = BASH_REMATCH[2] * sign1, frac1 = BASH_REMATCH[3] * sign1))
elif [[ "$1" =~ ^(-?)\.([[:digit:]]+)$ ]]; then
	((sign1 = ${#BASH_REMATCH[1]} > 0 ? -1 : 1, whole1 = 0, frac1 = BASH_REMATCH[2] * sign1))
else
	exit 127
fi
declare -ir sign1 whole1 frac1
shift
declare -r op="$2"
shift
declare -i sign2=0
declare -i whole2=0
declare -i frac2=0
if [[ "$1" =~ ^(-?)([[:digit:]]+)\.([[:digit:]]*)$ ]]; then
	((sign2 = ${#BASH_REMATCH[1]} > 0 ? -1 : 1, whole2 = BASH_REMATCH[2] * sign2, frac2 = BASH_REMATCH[3] * sign2))
elif [[ "$1" =~ ^(-?)\.([[:digit:]]+)$ ]]; then
	((sign2 = ${#BASH_REMATCH[1]} > 0 ? -1 : 1, whole2 = 0, frac2 = BASH_REMATCH[2] * sign2))
else
	exit 127
fi
declare -ir sign2 whole2 frac2

if ((whole1 == whole2 && frac1 == frac2 )); then
	if [ "$op" = '==' ] || [ "$op" = '<=' ] || [ "$op" = '>=' ] || [ "$op" = '=' ] || [ "$op" = '=<' ] || [ "$op" = '=>' ]; then
		exit 0
	else
		exit 1
	fi
elif ((whole1 > whole2)) || ((whole1 == whole2 && frac1 > frac2)); then
	if [ "$op" = '>' ] || [ "$op" = '>=' ] || [ "$op" = '=>' ]; then
		exit 0
	else
		exit 1
	fi
# elif ((whole1 < whole2)) || ((whole1 == whole2 && frac1 < frac2)); then
else
	if [ "$op" = '<' ] || [ "$op" = '<=' ] || [ "$op" = '=<' ]; then
		exit 0
	else
		exit 1
	fi
fi