produce-quote-args-output.bash

#!/bin/bash

test_args=(
	# 1-5: Standard system/portage strings
	"sys-apps/gentoo-functions"
	"--verbose"
	"USE=unicode"
	"CHOST=x86_64-pc-linux-gnu"
	"FEATURES=sandbox"

	# 6-10: File paths and patterns
	"/var/db/repos/gentoo"
	"*.patch"
	"./configure"
	"MAKEOPTS=-j16"
	"LDFLAGS=-Wl,-O1"

	# 11-15: Escapes, spaces, quotes, and symbols
	"escape_\E_sequence"
	"There's more to life than this"
	"space separated arg"
	'nested"quotes"here'
	"back\\slash\\test"

	# 16-20: Dynamic expansion characters
	'$variable_pattern'
	"\${escaped_dollar}"
	"simple"
	"!!!"
	"DONE=true"
)

_quote_args_bash() {
	local str= qw qw2 w

	for w; do
		printf -v qw %q "$w" || return

		if [[ ${qw} == "$w" ]]; then
			str+=\ $w
		elif [[ ${qw} == \$* ]]; then
			str+=\ ${qw//\\E/\\e}
		elif [[ $w == *\'* ]]; then
			if printf -v qw2 %q $'\e'"$w" && [[ ${qw2} == \$\'\\[Ee]* ]]; then
				str+=\ \$\'${qw2:4}
			else
				str+=\ ${qw}
			fi
		else
			str+=" '$w'"
		fi
	done

	printf %s\\n "${str# }"
}

quote_args() {
	if [ ! "${POSIXLY_CORRECT}" ] && [ "${BASH}" ] &&
			eval '(( BASH_VERSINFO > 3 || BASH_VERSINFO == 3 && BASH_VERSINFO[1] ))'; then
		_quote_args_bash "$@"
	else
		declare -p POSIXLY_CORRECT
		POSIXLY_CORRECT=${POSIXLY_CORRECT} shquote "$@"
	fi
}

quote_args "${test_args[@]}" "$@"