#### integers

let!() { let "$@" || true; } # always returns true; safe to use for setting

	# "If the last ARG evaluates to 0, let returns 1" (`help let`)

bool2int() { try test ! "$1"; echo "$e"; } # empty->0; non-empty->1

int2exit() { (( "$1" != 0 )); }

exit2bool() { if (( $? == 0 )); then echo 1; fi } # 0->non-empty; !=0->empty

#### floats

int_part() { echo "${1%%.*}"; }

dec_suffix() { echo "${1#$(int_part "$1")}"; }

round_down() { int_part "$1"; }

float+int() { echo "$(($(int_part "$1")+$2))$(dec_suffix "$1")"; }

float_set_min() { if (($(int_part $1) >= $2)); then echo $1; else echo $2; fi; }

#### strings

starts_with() { test "${2#$1}" != "$2"; } # usage: starts_with pattern str

ends_with() { test "${2%$1}" != "$2"; } # usage: ends_with pattern str

match_prefix() # usage: match_prefix pattern str

{ if starts_with "$1" "$2"; then echo "${2%${2#$1}}"; fi }

rm_prefix() { echo "${2#$1}"; } # usage: rm_prefix pattern str

contains_match() { starts_with "*$1" "$2"; } # usage: contains_match pattern str

repeat() # usage: str=... n=... repeat

{

	: "${str?}" "${n:?}"; local result= n="$n" # n will be modified in function

	for (( ; n > 0; n-- )); do result="$result$str"; done

	echo "$result"

}

# usage: outer_cmd $sed_cmd ...

sed_cmd="env LANG= sed -`case "$(uname)" in Darwin) echo El;; *) echo ru;;esac`"

	# LANG: avoid invalid UTF-8 "illegal byte sequence" errors when LANG=*.UTF-8

	# -l: line buffered / -u: unbuffered

alias sed="$sed_cmd"

	# can't be function because this causes segfault in redir() subshell when

	# used with make.sh make() filter

fi # load new aliases

if self_being_included; then

rtrim() { log_local; log+ 3; sed 's/[[:space:]]+$//' <<<"$1"; }

#### arrays

echo1() { echo "$1"; } # usage: echo1 values...

esc() # usage: array=($(log++; prep_env... (eg. cd); esc args...))

{ local arg; for arg in "$@"; do printf '%q ' "$arg"; done; }

# usage: split delim str; use ${parts[@]}

function split() { local IFS="$1"; parts=($2); echo_vars parts; }

	# no echo_func because used by log++

alias split='declare parts; "split"'

join() { local IFS="$delim"; echo "$*"; } # usage: delim=char join elems...

reverse() # usage: array=($(reverse args...))

{

	local i

	for (( i=$#; i > 0; i-- )); do printf '%q ' "${!i}"; done

}

contains() # usage: contains value in_array...

{

	local value="$1"; shift

	local elem

	for elem in "$@"; do if test "$elem" = "$value"; then return 0; fi; done

	return 1

}

is_array() # handles unset vars (=false)

{

	isset "$1" || return 1

	local decl; decl="$(declare -p "$1")" || return; echo_vars decl

	starts_with 'declare -a' "$decl" # also matches -ax

}

fi # load new aliases

if self_being_included; then