#!/bin/bash -e

set -o errexit -o pipefail # errexit in case caller's #! line missing -e

if test ! "$_util_sh_include_guard_utils"; then

_util_sh_include_guard_utils=1

isset() { declare -p "$1" &>/dev/null; }

realpath() { readlink -f -- "$1"; }

lowercase() { tr A-Z a-z <<<"$1"; }

str2varname() { lowercase "${1//[^a-zA-Z0-9_]/_}"; }

	# lowercase: on case-insensitive filesystems, paths sometimes canonicalize

	# to a different capitalization than the original

include_guard_var() { str2varname "$(realpath "$1")"; }

self_not_included() # usage: if self_not_included; then ... fi

{

	test $# -ge 1 || set -- "${BASH_SOURCE[1]}"

	local include_guard="$(include_guard_var "$1")"

	alias self_being_included=false

	! isset "$include_guard" && \

	{ eval "$include_guard"=1; alias self_being_included=true; }

}

# to load newly-defined aliases for use in functions in the same file:

## fi # load new aliases

## if self_being_included; then

# this is needed because aliases defined inside an if statement are not

# available inside that if statement

fi

if self_not_included "${BASH_SOURCE[0]}"; then

#### options

shopt -s expand_aliases

# **DON'T** do `shopt -s lastpipe` because this causes a segfault on Linux in

# stderr_matches(). (it also isn't supported on Mac.) use @PIPESTATUS instead.

#### stubs

die()

{ return "$?"; } # can't use `:` because that resets $?

alias log_local='declare PS4="$PS4" log_level="$log_level"'

function log++() { :; }

alias log++='"log++" ' # last space alias-expands next word

alias log--='"log--" ' # last space alias-expands next word

alias log!='"log!" ' # last space alias-expands next word

function log() { :; }

__caller_indent='log_indent="$log_indent$log_indent_step"'

alias caller_indent="$__caller_indent"

alias indent="declare $__caller_indent"

function canon_rel_path() { echo "$1"; }

function echo_func() { :; }

alias echo_func='"echo_func" "$FUNCNAME" "$@" && indent || true'

function echo_run() { :; }

alias echo_run='"echo_run" ' # last space alias-expands next word

# auto-echo common external commands

for cmd in env rm which; do alias "$cmd=echo_run $cmd"; done; unset cmd

echo_builtin() { :; }

function echo_vars() { :; }

#### logic

not() { ! "$@"; } # usage: wrapper_cmd not wrapped_cmd... # inverts exit status

bool!() # usage: "$(bool! "$bool_var")"

{ if test ! "$1"; then echo -n 1; fi } # empty<->non-empty

#### vars

alias local_array='declare -a'

	# `local` does not support arrays in older versions of bash/on Mac

set_var() { eval "$1"'="$2"'; }

set_default() { if ! isset "$1"; then set_var "$@"; fi; }

set_inv() { set_var no_"$1" "$(test "${!1}" || echo 1)"; }

# usage: local var=...; local_inv

alias local_inv=\

'declare "no_$var=$(test "${!var}" || echo 1)"; echo_vars no_$var'

unexport() { export -n "$@"; }

	# `declare +x` won't work because it defines the var if it isn't set

alias local_export='declare -x' # combines effects of local and export

alias export_array='declare -ax'

	# `export` does not support arrays in older versions of bash/on Mac

# to make export only visible locally: local var="$var"; export var

# within cmd: var="$var" cmd...

get_prefix_vars() { : "${prefix:?}"; eval echo '${!'$prefix'*}'; }

# usage: local prefix=..._; import_vars

# when used inside another alias 2+ levels deep, *must* be run inside a function

# idempotent: vars already set will *not* be overwritten

alias import_vars="$(cat <<'EOF'

: "${prefix:?}"

declare src_var dest_var

for src_var in $(get_prefix_vars); do

	dest_var="${src_var#$prefix}"

	# use ${...-...} to avoid overwriting an already-set var

	declare "$dest_var=${!dest_var-${!src_var}}"; echo_vars "$dest_var"

done

EOF

)"

#### 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() { split__with_IFS "$@"; echo_vars parts; }

	# no echo_func because used by log++

split__with_IFS() { local IFS="$1"; parts=($2); } # limit effects of IFS

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

}

#### terminal

### formatting

has_bg()

{

	# inverse (black background)/set background (normal colors)/set background

	# (bright colors) (xfree86.org/current/ctlseqs.html#Character_Attributes)

	starts_with 7 "$1" || starts_with 4 "$1" || starts_with 10 "$1"

}

format() # usage: format format_expr msg

# format_expr: the #s in xfree86.org/current/ctlseqs.html#Character_Attributes

{

	local format="$1" msg="$2"

	if starts_with '[' "$msg"; then format=; fi #don't add padding if formatted

	if has_bg "$format"; then msg=" $msg "; fi # auto-add padding if has bg

	echo "${format:+[0;${format}m}$msg${format:+}"

}

plain() { echo "$1"; }

fade() { format 90 "$@"; } # medium gray fades on white *&* black backgrounds

#### errors

err_fd=2 # stderr

# usage: local func=...; set_func_loc; use $file, $line

alias set_func_loc="$(cat <<'EOF'

: "${func:?}"

local func_info="$(shopt -s extdebug; declare -F "$func")" # 'func line file'

func_info="${func_info#$func }"

local line="${func_info%% *}"

local file="${func_info#$line }"

EOF

)"

fi # load new aliases

if self_being_included; then

func_loc() # gets where function declared in the format file:line

{

	local func="$1"; set_func_loc

	file="$(canon_rel_path "$file")" || return

	echo "$file:$line"

}

### stack traces

alias init_i='declare i="${i-0}"'

alias next_stack_frame='let! i++'

# makes stack_trace() skip the entry for the caller

alias skip_stack_frame='init_i; next_stack_frame'

fi # load new aliases

if self_being_included; then

# usage: [i=#] get_stack_frame # i: 0-based index from top of stack

# to get all stack frames:

# init_i; while get_stack_frame; do use $func $file $line; next_stack_frame;done

# better than `caller` builtin because returns info in separate vars

get_stack_frame()

{

	skip_stack_frame; init_i

	# the extra FUNCNAME/BASH_LINENO entries have dummy values (main/0)

	func="${FUNCNAME[$i]}" # the called function, which = the current function

	file="${BASH_SOURCE[$i+1]}" # not the *current* file, but the call's file

	line="${BASH_LINENO[$i]}" # the line the function was called at

	test "$file" # exit false if invalid index

}

alias get_stack_frame='declare func file line && "get_stack_frame"'

	# && instead of ; so it can be used as a while cond

#### debugging

debug_fd="$err_fd"

ps() { echo "$@" >&"$debug_fd"; } # usage: ps str...

pv() { declare -p "$@" >&"$debug_fd"; } # usage: pv var... # debug-prints vars

pf() { declare -f "$@" >&"$debug_fd"; } # usage: pf func... # prints func decls

#### caching

## shell-variable-based caching

# usage: local cache_key=...; load_cache; \

# if ! cached; then save_cache value || return; fi; echo_cached_value

# cache_key for function inputs: "$(declare -p kw_param...) $*"

alias load_cache='declare cache_var="$(str2varname "${FUNCNAME}___$cache_key")"'

alias cached='isset "$cache_var"'

alias save_cache='set_var "$cache_var"'

alias echo_cached_value='echo "${!cache_var}"'

clear_cache() # usage: func=... clear_cache

{ : "${func:?}"; unset $(prefix="${func}___" get_prefix_vars); }

fi # load new aliases

if self_being_included; then

#### functions

func_exists() { declare -f "$1" >/dev/null; }

kw_params() # usage: func() { kw_params param_var...; }; ...; param_var=... cmd

# removes keyword-param-only vars from the environment

{ unexport "$@"; }

1st_non_opt() { while starts_with - "$1"; do shift; done; echo "$1"; }

# usage: cmd=... foreach_arg

function foreach_arg()

{

	echo_func; kw_params cmd; : "${cmd:?}"

	local a; for a in "$@"; do

		a="$(log++ echo_run "$cmd" "$a")" || return; args+=("$a")

	done

	echo_vars args

}

alias foreach_arg='"foreach_arg" "$@"; set -- "${args[@]}"; unset args'

alias self_name='echo "${FUNCNAME%%__*}"' # usage: "$(self_name)"

alias self='command "$(self_name)"' # usage: wrapper() { self ...; }

alias self_sys='sys_cmd "$(self_name)"' # wrapper() { self_sys ...; }

alias self_builtin='builtin "${FUNCNAME%%__*}"' #wrapper() { self_builtin ...; }

all_funcs() # usage: for func in $(all_funcs); do ...; done # all declared funcs

{ declare -F|while read -r line; do echo -n "${line#declare -f } "; done; }

copy_func() # usage: from=... to=... copy_func

# $to must not exist. to get around the no-clobber restriction, use `unset -f`.

{

	log++ echo_func

	: "${from:?}" "${to:?}"

	func_exists "$from" || die "function does not exist: $from"

	! func_exists "$to" || die "function already exists: $to"

	local from_def="$(declare -f "$from")"

	eval "$to${from_def#$from}"

}

func_override() # usage: func_override old_name__suffix

{ log++ echo_func; from="${1%__*}" to="$1" copy_func; }

ensure_nested_func() # usage: func__nested_func() { ensure_nested_func; ... }

{

	local nested_func="${FUNCNAME[1]}"

	local func="${nested_func%%__*}"

	contains "$func" "${FUNCNAME[@]}" || \

		die "$nested_func() must be used by $func()"

}

#### aliases

fi # load new aliases

if self_being_included; then

unalias() { self_builtin "$@" 2>&- || true; } # no error if undefined

# usage: alias alias_='var=value run_cmd '

function run_cmd() { "$@"; }

alias run_cmd='"run_cmd" ' # last space alias-expands next word

alias_append() { eval "$(alias "$1")"'"$2"';} #usage: alias_append alias '; cmd'

#### commands

type() # handles fact that any alias would already be expanded

{ (unalias "$(1st_non_opt "$@")"; self_builtin "$@") || return; }

is_callable() { type -t -- "$1" >/dev/null; }

is_extern() { test "$(type -t -- "$1")" = file; }

is_intern() { is_callable "$1" && ! is_extern "$1"; }

is_dot_script()

{ log_local;log++; echo_func; test "${BASH_LINENO[${#BASH_LINENO[@]}-1]}" != 0;}

require_dot_script() # usage: require_dot_script || return

{

	echo_func

	if ! is_dot_script; then # was run without initial "."

		echo "usage: . $top_script (note initial \".\")"|fold -s >&2

		return 2

	fi

}

sys_cmd_path() { echo_func; echo_builtin command -p which "$1"|echo_stdout; }

# makes command in $1 a system command

# allows running a system command of the same name as the script

alias cmd2sys="$(cat <<'EOF'

declare _1="$1"; shift

_1="$(indent; log++ sys_cmd_path "$_1")" || return

set -- "$_1" "$@"

EOF

)"

fi # load new aliases

if self_being_included; then

sys_cmd() { cmd2sys; command "$@"; } # usage: sys_cmd cmd... # runs system cmd

	# allows running a system command of the same name as the script

function sudo()

{

	echo_func

	if is_callable "$1"; then set -- env PATH="$PATH" "$@"; fi # preserve PATH

	self -E "$@"

}

alias sudo='"sudo" ' # last space alias-expands next word

#### exceptions

fi # load new aliases

if self_being_included; then

exit() { self_builtin "${1:-$?}"; } # exit sometimes inxeplicably ignores $?

errexit() # usage: cmd || errexit status # works in functions *and* subshells

{ return "$1"; }

	# can't use `(exit "$1")` because a bug in bash prevents subshells from

	# triggering errexit (would need to append `|| return` for it to work)

# usage: cmd || { save_e; ...; rethrow; }

alias export_e='e=$?'

# **WARNING**: if using this after a command that might succeed (rather than

# only upon error), you must `unset e` before the command

# idempotent: also works if save_e already called

alias save_e='# idempotent: use $e if the caller already called save_e

declare e_=$?;

declare e="$(if test "$e_" = 0; then echo "${e:-0}"; else echo "$e_"; fi)"'

rethrow() { errexit "${e:-0}"; } # only does anything if $e != 0

rethrow!() { rethrow && false; } # always errexit, even if $e = 0

rethrow_exit() { rethrow || exit; } # exit even where errexit disabled

is_err() { ! rethrow; } # rethrow->*false* if error

fi # load new aliases

if self_being_included; then

# usage: try cmd...; ignore_e status; if catch status; then ...; fi; \

# finally...; end_try

alias prep_try='declare e=0 benign_error="$benign_error"'

# usage: ...; try cmd... # *MUST* be at beginning of statement

#     OR prep_try; var=... "try" cmd...

function try() { benign_error=1 "$@" || { export_e; true; }; }

alias try='prep_try; "try" ' # last space alias-expands next word

catch() { test "$e" = "${1:-0}" && e=0; } # also works w/ $1=''

ignore_e() { if catch "$@"; then benign_error=1; fi; } # also works w/ $1=''

alias end_try='rethrow'

ignore() { save_e; ignore_e "$@"; rethrow; } # usage: try cmd || ignore status

### signals

sig_e() { echo $(( 128+$(kill -l "$1") )); } # usage: sig_e SIGINT, etc.

func_override catch__exceptions

catch() # supports SIG* as exception type

{

	log_local; log++; echo_func

	if starts_with SIG "$1"; then set -- "$(sig_e "$1")"; fi

	catch__exceptions "$@"

}

# usage: piped_cmd cmd1...|cmd2... # cmd2 doesn't read all its input

function piped_cmd() { "$@" || ignore SIGPIPE; }

alias piped_cmd='"piped_cmd" ' # last space alias-expands next word

fi # load new aliases

if self_being_included; then

#### text

nl='

'

# usage: by itself:                            split_lines  str; use ${lines[@]}

#        with wrapper: declare lines; wrapper "split_lines" str; use ${lines[@]}

function split_lines() { split "$nl" "$1"; lines=("${parts[@]}"); }

	# no echo_func because used by log++

alias split_lines='declare lines; "split_lines"'

#### paths

strip/() { echo "${1%/}"; } # strips trailing /s

wildcard/() # usage: array=($(log++; [cd ...;] wildcard/ unquoted_pattern...))

{ cmd=strip/ foreach_arg; esc "$@"; }

wildcard.() # usage: array=($(log++; [cd ...;] wildcard. unquoted_pattern...))

# currently only removes . .. at beginning of list

{

	set -- $(wildcard/ "$@") # first strip trailing /s

	local to_rm=(. ..)

	local item

	if contains "$1" "${to_rm[@]}"; then

		shift

		if contains "$1" "${to_rm[@]}"; then shift; fi

	fi

	esc "$@"

}

#### streams

pipe_delay() # usage: cmd1 | { pipe_delay; cmd2; }

{ sleep 0.1; } # s; display after leading output of cmd1

#### verbose output

usage() { echo "Usage: $1" >&2; return 2; }

### log++

log_fd=2 # initially stderr

if test "$explicit_errors_only"; then verbosity=0; fi # hide startup logging

# set verbosity

if isset verbose; then : "${verbosity:=$(bool2int "$verbose")}"; fi

if isset vb; then : "${verbosity:=$vb}"; fi

: "${verbosity=1}" # default

: "${verbosity:=0}" # ensure non-empty

export verbosity # propagate to invoked commands

is_outermost="$(! isset log_level; exit2bool)" # if util.sh env not yet set up

# set log_level

: "${log_level=$(( ${#PS4}-1 ))}" # defaults to # non-space symbols in PS4

export log_level # propagate to invoked commands

export PS4 # follows log_level, so also propagate this

verbosity_int() { round_down "$verbosity"; }

# verbosities (and `make` equivalents):

# 0: just print errors. useful for cron jobs.

#    vs. make: equivalent to --silent, but suppresses external command output

# 1: also external commands run. useful for running at the command line.

#    vs. make: not provided (but sorely needed to avoid excessive output)

# 2: full graphical call tree. useful for determining where error occurred.

#    vs. make: equivalent to default verbosity, but with much-needed indents

# 3: also values of kw params and variables. useful for low-level debugging.

#    vs. make: not provided; need to manually use $(error $(var))

# 4: also variables in util.sh commands. useful for debugging util.sh.

#    vs. make: somewhat similar to --print-data-base

# 5: also variables in logging commands themselves. useful for debugging echo_*.

#    vs. make: not provided; need to search Makefile for @ at beginning of cmd

# 6+: not currently used (i.e. same as 5)

# definition: the log_level is the minimum verbosity needed to display a message

# for messages that use can_log(), the log_level starts with *1*, not 0

# for unfiltered messages, the log_level is 0 (i.e. still output at verbosity=0)

# to view a message's log_level, count the # of + signs before it in the output

fi # load new aliases

if self_being_included; then

# usage: in func:      log_local; log++; ...

#        outside func: log_local; log++; ...; log--

#        before cmd:   log++ cmd  OR  log+ num cmd  OR  log++ log++... cmd

# with a cmd, assignments are applied just to it, so log_local is not needed

# without a cmd, assignments are applied to caller ("$@" expands to nothing)

# "${@:2}" expands to all of $@ after *1st* arg, not 2nd ($@ indexes start at 1)

log:() # sets explicit log_level

{

	if test $# -gt 1; then log_local; fi # if cmd, only apply assignments to it

	# no local vars because w/o cmd, assignments should be applied to caller

	log_level="$1"

	PS4="$(str="${PS4:0:1}" n=$((log_level-1)) repeat)${PS4: -2}"

	"${@:2}"

}

log+() { log: $((log_level+$1)) "${@:2}"; }

log-() { log+ "-$1" "${@:2}"; }

# no log:/+/- alias needed because next word is not an alias-expandable cmd

function log++() { log+ 1 "$@"; }

function log--() { log- 1 "$@"; }

function log!() { log: 0 "$@"; } # force-displays next log message

# see aliases in stubs

verbosity_min() # usage: verbosity_min {<min>|''}

# WARNING: '' is a special value that causes $verbosity to be overwritten to ''

{ if test ! "$1" -o "$(verbosity_int)" -lt "$1"; then verbosity="$1"; fi; }

alias verbosity_min='declare verbosity="$verbosity"; "verbosity_min"'

# usage: (verbosity_compat; cmd)

function verbosity_compat()

{ log_local; log++; echo_func; if ((verbosity == 1)); then unset verbosity; fi;}

alias verbosity_compat='declare verbosity="$verbosity"; "verbosity_compat"'

# indent for call tree. this is *not* the log_level (below).

: "${log_indent_step=| }" "${log_indent=}"

export log_indent_step log_indent # propagate to invoked commands

# see indent alias in stubs

fi # load new aliases

if self_being_included; then

can_log() { test "$log_level" -le "$(verbosity_int)"; }

	# verbosity=0 turns off all logging

can_highlight_log_msg() { test "$log_level" -le 1; }

highlight_log_msg() # usage: [format=...] highlight_log_msg msg

# format: the # in xfree86.org/current/ctlseqs.html#Character_Attributes

{

	log_local; log+ 2; echo_func; kw_params format; log- 2

	local format="${format-1}" # bold

	if ! can_highlight_log_msg; then format=0; fi #remove surrounding formatting

	format "$format" "$1"

}

log_line!() # highlights log_level 1 messages to stand out against other output

{ echo "$log_indent$PS4$(highlight_log_msg "$1")" >&"$log_fd"; }

log_msg!()

{

	declare lines; log+ 2 "split_lines" "$1"

	local l; for l in "${lines[@]}"; do log_line! "$l"; done

}

log() { if can_log; then log_msg! "$@"; fi; }

log_custom() # usage: symbol=... log_custom msg

{ log_indent="${log_indent//[^ ]/$symbol}" PS4="${PS4//[^ ]/$symbol}" log "$@";}

bg_r='101;97' # red background with white text

log_err() { symbol='#' format="$bg_r" log_fd="$err_fd" log! log_custom "$@";}

log_info() { symbol=: log_custom "$@"; }

mk_hint() { format=7 highlight_log_msg "$@";}

log_err_hint!() { log_err "$(mk_hint "$@")"; }

log_err_hint() # usage: cmd || [benign_error=1] log_err_hint msg [|| handle err]

# msg only displayed if not benign error

{

	log++ kw_params benign_error

	if test ! "$benign_error"; then log_err_hint! "$@"; fi

}

die() # usage: if msg uses $(...):    cmd || { save_e; [type=...] die msg; }

#              if msg uses only vars: cmd || [type=...] die msg

{ save_e; log++ kw_params type; "log_${type:-err}" "$1"; rethrow!; }

die_e() # usage: cmd || [benign_error=1] die_e [|| handle error]

{

	save_e; log++ kw_params benign_error

	if test "$e" = "$(sig_e SIGPIPE)"; then benign_error=1; fi

	if test "$benign_error"; then log_local; log++; fi

	type="${benign_error:+info}" die "command exited with \

$(if test "$benign_error"; then echo status; else echo error; fi) $e"

	rethrow

}

die_error_hidden() # usage: cmd || verbosity_min=# die_error_hidden [|| ...]

{

	save_e; log++ echo_func; log++ kw_params verbosity_min

	: "${verbosity_min:?}"; log++ echo_vars verbosity

	if test "$(verbosity_int)" -lt "$verbosity_min"; then

		log_err_hint 'to see error details, prepend `vb='"$verbosity_min"'` to the command'

	fi

	rethrow

}

#### paths

# cache realpath

: "${realpath_cache=}" # default off because slower than without

if test "$realpath_cache"; then

func_override realpath__no_cache

realpath() # caches the last result for efficiency

{

	local cache_key="$*"; load_cache

	if ! cached; then save_cache "$(realpath__no_cache "$@")" || return; fi

	echo_cached_value

}

fi

rel_path() # usage: base_dir=... path=... rel_path

{

	log_local; log++; kw_params base_dir path

	: "${base_dir:?}" "${path:?}"

	local path="$path/" # add *extra* / to match path when exactly = base_dir

	path="${path#$base_dir/}" # remove prefix shared with base_dir

	path="${path%/}" # remove any remaining extra trailing /

	if test ! "$path"; then path=.; fi # ensure non-empty

	echo_vars path

	echo "$path"

}

cd -P . # expand symlinks in $PWD so it matches the output of realpath

# do before setting $top_script_abs so realpath has less symlinks to resolve

canon_rel_path() # usage: [base_dir=...] canon_rel_path path

# falls back to original path if can't resolve

{

	kw_params base_dir; local path="$1" base_dir="${base_dir-$PWD}"

	canon_rel_path__try || echo "$path"

}

canon_rel_path__try()

{

	ensure_nested_func

	base_dir="$(realpath "$base_dir")" || return

	path="$(realpath "$path")" || return

	rel_path

}

canon_dir_rel_path() # usage: [base_dir=...] canon_dir_rel_path path

# if the path is a symlink, just its parent dir will be canonicalized

{

	kw_params base_dir; local base_dir="${base_dir-$PWD}"

	base_dir="$(realpath "$base_dir")" || return

	local path; path="$(realpath "$(dirname "$1")")/$(basename "$1")" || return

	rel_path

}

# makes $1 a canon_rel_path if it's a filesystem path

alias cmd2rel_path="$(cat <<'EOF'

if is_extern "$1" && test -e "$1"; then # not relative to PATH

	declare _1="$1"; shift

	_1="$(log++ canon_rel_path "$_1")" || return

	set -- "$_1" "$@"

fi

EOF

)"

# usage: path_parents path; use ${dirs[@]} # includes the path itself

function path_parents()

{

	echo_func; local path="$1" prev_path=; dirs=()

	while test "$path" != "$prev_path"; do

		prev_path="$path"

		dirs+=("$path")

		path="${path%/*}"

	done

}

alias path_parents='declare dirs; "path_parents"'

#### verbose output

### command echoing

alias echo_params='log "$*"'

fi # load new aliases

if self_being_included; then

echo_cmd() { echo_params; }

function echo_run() { echo_params; "$@"; }

# see echo_run alias after stub

echo_builtin() { echo_run builtin "$@"; } # usage: echo_builtin builtin_cmd...

echo_eval() { echo_params; builtin eval "$@"; }

## vars

echo_vars() # usage: echo_vars var... # also prints unset vars

{

	log_local; log++ # same log_level as echo_func

	if can_log; then

		local set_exprs= shared_flags=

		local var; for var in "${@%%=*}"; do

			if ! isset "$var"; then declare "$var"='<unset>'; fi

			# merge repeated flags

			local decl="$(declare -p "$var")"; decl="${decl#declare }"

			local flags="${decl%% *}" def="${decl#* }"

			if test ! "$shared_flags"; then shared_flags="$flags"; fi

			if test "$flags" != "$shared_flags"; then

				set_exprs="$set_exprs$flags "

			fi

			set_exprs="$set_exprs$def "

		done

		# put all vars on same line so they don't clutter up the logging output

		log "declare $shared_flags $set_exprs"

	fi

}

echo_export() { builtin export "$@"; echo_vars "$@"; }

alias export="echo_export" # automatically echo env vars when they are set

func_override kw_params__lang

kw_params() { kw_params__lang "$@"; echo_vars "$@"; } # echo all keyword params

## functions

# usage: func() { echo_func; ... }

function echo_func()

# usage: "echo_func" "$FUNCNAME" "$@" && indent || true

# exit status: whether function call was echoed

{

	log_local; log++; can_log || return

	local func="$1"; shift

	local loc; loc="$(log++ func_loc "$func")" || return

	echo_cmd "$func" "$@" "   $(plain "@$loc")"

}

# see echo_func alias after stub

fi # load new aliases

if self_being_included; then

#### fds

fd_exists() { (: <&"$1") 2>/dev/null; }

require_fd_not_exists() # usage: require_fd_not_exists fd || return 0

{ ! fd_exists "$1" || type=info die "fd $1 already exists, skipping"; }

set_fds() # usage: set_fds redirect...

# WARNING: does not currently support redirecting an fd to itself (due to bash

# bug that requires the dest fd to be closed before it can be reopened)

{

	echo_func

	# add #<>&- before every #<>&# reopen to fix strange bash bug

	local redirs=() i

	for i in "$@"; do

		# remove empty redirects resulting from using `redirs= cmd...` to clear

		# the redirs and then using $redirs as an array

		if test "$i"; then

			local redir_prefix="$(match_prefix '*[<>]' "$i")"

			local dest="$(        rm_prefix    '*[<>]' "$i")"

			if test "$dest" && ! starts_with '&' "$dest"; then # escape dest

				i="$redir_prefix$(printf %q "$dest")"

			fi

			if test "$redir_prefix"; then redirs+=("$redir_prefix&-"); fi

			redirs+=("$i")

		fi

	done

	set -- "${redirs[@]}"

	if (($# > 0)); then echo_eval exec "$@"; fi

}

fd_set_default() # usage: fd_set_default 'dest[<>]src'