Log message:
mksh: fix typos in DESCR

Log message:
Update mksh to R57.

R57 rolls up bugfixes, with few hard changes:

  * [gecko2] Update operating environment reporting for the Macintosh
  * [Martijn Dekker] make ${foo#'bar'} in here document behave like ksh93
  * [Martijn Dekker] quote empty strings for re-entry into shell
  * [tg, G.raud Meyer] Improve documentation, especially for tty states
  * [tg] Protect against entering line editing with bad saved tty state
  * [tg] Fix set -o allexport for arrays (which we apparently do)
  * [tg] Handle lseek(2) returning -1 as pointed out by Coverity Scan
  * [tg] Fix left-padding UTF-8 strings
  * [tg, G.raud Meyer] Fix using the ?-m? flag on the command line
  * [tg] Update to UCD 11.0.0
  * [multiplexd] Fix a segfault using ^W during search in Vi mode
  * [tg] Fix an error message; add a test for controlling tty
  * [tg] Permit unsetting LINES and COLUMNS, for those who need it
  * [tg] Fix manpage bug (RedHat BZ#1612173)
  * [tg] Minor spelling cleanup
  * [tg] Unbreak high-bit7 (n?n-ASCII) heredoc separators (LP#1779179)
  * [tg] Allow dumping high-bit7-char-containing strings in DEBUG mode
  * [tg] Add some testcases for behaviour questions popped up in IRC
  * [tg] Trick a GCC warning, to make up for it ignoring lint(1) hints
  * [tg] Add O_MAYEXEC support for CLIP OS
  * [tg] Make dup-to-self with ksh-style fd?3 closing work; catern via IRC
  * [tg] Add compat glue for newer GNU groff mdoc to the manpages
  * [tg] Trigger EXIT trap after single-command subshells (Debian #910276)
  * [tg] Document set -eo pipefail caveat (LP#1804504)
  * [tg] Fix MKSH_EARLY_LOCALE_TRACKING warning
  * [tg] Document that, when your Unix is broken, GIGO applies (LP#1817959)
  * [tg] Improve error message for inaccessible executables (LP#1817789)

Log message:
Update mksh to 56c.

R56c is a bugfix-only release everyone must upgrade to:

- [komh] Remove redundant OS/2-specific code, clean up others
- [komh, tg] Fix drive-qualified (absolute and relative) DOS-style path support
  in realpath functionality, partially other places
- [tg] Don't substitute ${ENV:-~/.mkshrc} result again
- [tg] Improve OS/2 $PATH (et al.) handling, drive-relative paths
- [tg] Add MKSH_ENVDIR compile-time option for Jehanne and Plan 9
- [tg] Limit nesting when parsing malformed code (Debian #878947)
- [tg] Update wcwidth data with bugfixed script (still Unicode 10; resulting
  values are identical to glibc git master for extant chars)
- [Dr. Werner Fink] Raise some time limits in the testsuite
- [Shamar] Add support for the Jehanne operating system
- [komh] Set stdin to text mode before executing child processes on OS/2
- [komh] Pass arguments via a resonse file if executing a child fails
- [Dr. Werner Fink] Early locale tracking as a compile-time option
- [tg] Fix regressions introduced with new fast character classes

Log message:
Update mksh to R56b.

R56b is a bugfix-only release everyone should upgrade to:

- [tg] Reference the FAQ webpage
- [panpo, Riviera] Fix documentation bug wrt. Esc+Ctrl-L
- [tg, Larry Hynes] Fix '0' movement in vi mode
- [tg] Replace broken libcs' offsetof macro with MirBSD's

R56 is a bugfix release with some experimental fixes:

- [tg, Seb] Do not apply alias name restrictions to hash/tilde tracking
- [tg] Restore '.', ':' and '[' in alias names ('[[' is still forbidden)
- [tg] Fix accidentally defanged $PATHSEP test
- [tg] On ^C (INTR and QUIT edchars), shove edit line into history
- [iSKUNK, tg] Begin porting to z/OS using EBCDIC encoding, incomplete
- [tg] Redo fast character classes code, adding POSIX and other helpers
- [tg] bind parses backslash-escaped '^' (and '\') as escaped
- [tg] Building with -DMKSH_ASSUME_UTF8=0 no longer causes a known failure in
  the testsuite
- [tg] New test.sh option -U to pass a UTF-8 locale to use in the tests
- [tg] re_format(7) BSD: [[ $x = *[[:\<:]]foo[[:\>:]]* ]]
- [tg, iSKUNK] Use Config in check.pl only if it exists
- [tg] New matching code for bracket expressions, full POSIX (8bit)
- [komh] Exclude FAT/HPFS/NTFS-unsafe tests on OS/2 (and Cygwin/MSYS)
- [tg] Update to Unicode 10.0.0
- [tg, selk] Make readonly idempotent
- [tg, multiplexd] When truncating the persistent history, do not change the
  underlying file, do all operations on the locked one; do not stop using the
  history at all if it has been truncated
- [tg, J?rg] Turn off UTF-8 mode upon turning on POSIX mode
- [Martijn Dekker, Geoff Clare, many on the Austin list, tg] In POSIX mode,
  make the exec builtin force a $PATH search plus execve
- [tg] Fix GCC 7, Coverity Scan warnings
- [tg, Michal Hlavinka] Track background process PIDs even interactive
- [tg] Always expose mksh's hexdump shell function; speed it up by working on
  the input in chunks; use character classes to make it EBCDIC safe
- [tg] Revamp dot.mkshrc default editor selection mechanism

Log message:
Update mksh to R55.

R55 is mostly a feature release with summary bugfixes:

  * [komh] Fix OS/2 search_access() and UNC path logic
  * [tg] Undocument printf(1) to avoid user confusion
  * [Jean Delvare, tg] Fix printf builtin -R option
  * [tg] Make ${var@x}, unknown x, fail (thanks izabera)
  * [tg] ${var=x} must evaluate x in scalar context (10x Martijn Dekker)
  * [tg] Fixup relation between lksh and mksh, reduce delta
  * [tg] Improve manpage display; add OS/2 $PATH FAQ
  * [Jean Delvare] Fix bugs in manpage
  * [tg] Review tilde expansion, removing ?odd use of KEEPASN? and introduce
    POSIX ?declaration utility? concept; wait isn?t one
  * [tg] Add \builtin utility, declaration utility forwarder
  * [tg] Make $'\xz' expand to xz, not \0
  * [tg] Use fixed string pooling (requires the above change in host mksh)
  * [tg] POSIX declaration commands can have varassign and redirections
  * [Martijn Dekker] Add typeset -g, replacing homegrown ?global?
  * [Harvey-OS] Disable NOPROSPECTOFWORK, APEX is reportedly fixed now
  * [tg] Display ulimit -a output with flags; improve Haiku
  * [tg] Drop old let] hack, use \builtin internally
  * [tg] Fix padding in Lb64encode in dot.mkshrc
  * [tg] Move FAQ content to a separate, new FAQ section in the manpage
  * [tg] Add new standard variable PATHSEP (?:?, ?;? on OS/2)
  * [Martijn Dekker] Fix LINENO in eval and alias
  * [komh] Fix ?\builtin? on OS/2
  * [tg] Improve (internal) character classes code for speed
  * [tg] Fix: the underscore is no drive letter
  * [tg] No longer hard-disable persistent history support in lksh
  * [tg] Introduce build flag -T for enabling ?textmode? on OS/2 (supporting
    CR+LF line endings, but incompatible with mksh proper)
  * [tg] Merge mksh-os2
  * [tg] Permit changing $OS2_SHELL during a running shell
  * [tg] Fix multibyte handling in ^R (Emacs search-history)
  * [tg] Allow ?typeset -p arrname[2]? to work
  * [tg] Make some error messages more consistent
  * [tg, komh] Disable UTF-8 detection code for OS/2 as unrealistic
  * [tg, sdaoden] Limit alias name chars to POSIX plus non-leading ?-?
  * [tg, Martijn Dekker] Expand aliases at COMSUB parse time
  * [tg] Make ?typeset -f? output alias-resistent
  * [tg, Martijn Dekker] Permit ?eval break? and ?eval continue?
  * [tg] Make -masm=intel safe on i386
  * [tg] Disambiguate $((?)) vs. $((?)?) in ?typeset -f? output
  * [Jean Delvare] Clarify the effect of exit and return in a subshell
  * [tg] Simplify compile-time asserts and make them actually compile-time
  * [tg] Fix ^O in Emacs mode if the line was modified (LP#1675842)
  * [tg] Address Coverity Scan? stuff? now that it builds again
  * [Martijn Dekker, tg] Add test -v
  * [tg] Document set -o posix/sh completely

R54 is a bugfix release with moderate new features:

  * [tg] Simplify and improve code and manual page
  * [tg] Try GCC 5?s new -malign-data=abi
  * [tg] Allow interrupting builtin cat even on fast devices (LP#1616692)
  * [tg] Update to Unicode 9.0.0
  * [Andreas Buschka] Correct English spelling
  * [tg] Handle set -e-related error propagation in || and && constructs
    correctly
  * [tg] Initialise memory for RNG even when not targeting Valgrind
  * [tg] Shrink binary size
  * [Brian Callahan] Improve support for the contemporary pcc compiler
  * [tg] Fix side effects with lazy evaluation; spotted by ormaaj
  * [tg] New flags -c (columnise), -l, -N for the print builtin
  * [Larry Hynes] Fix English, spelling mistakes, typos in the manpage
  * [tg, ormaah] Return 128+SIGALRM if read -t times out, like GNU bash
  * [Martijn Dekker] Install both manpages from Build.sh
  * [Martijn Dekker] Document case changes are ASCII-only
  * [Ronald G. Minnich, Elbing Miss, ?lvaro Jurado, tg] Begin porting to
    Harvey-OS and APEX (similar to Plan 9 and APE)
  * [KO Myung-Hun] More infrastructure for the OS/2 (EMX, KLIBC) port

R53a is a snapshot/feature release:

  * [lintian] Fix spelling
  * [tg] Unbreak multi-line command history broken by history flush
  * [tg] Fix redefining POSIX functions that were Korn functions before
  * [tg, TNF] Fix bounds checks in Vi editing mode
  * [tg] Handle combining characters at end of string or output correctly
  * [tg] Fix ${!#} ${!?} ${!-} (POSIX, prompted by izabera)
  * [tg] Fix shf.c-internal buffer overread on printing digits
  * [J?rg] Fix a typo in the testsuite
  * [arekm] Increase default edit line size (unless MKSH_SMALL)
  * [tg] Improve description of Emacs mode keybindings, especially ^U
  * [tg, arekm, jilles] Abort read builtin in case of read(2) errors
  * [tg, izabera, carstenh] Fix most of the ambiguous corner cases related to $
    {[pfx]var[op[word]]} (${@:-1} still unsupported)
  * [carstenh] Contribute some more testsuite coverage
  * [tg] WDS_TPUTS now emits QCHAR newline reentrant-safe
  * [tg] Fix var=<< implementation (LP#1380389)
  * [tg, FreeBSD] Make XSI test(1) extensions behave as if they were POSIX
  * [tg, izabera] Add $(<<<x) and $(<<EOF?) implementation
  * [tg] Lower minimum screen size accepted as ?sane? from the OS to 4?2
  * [tg, Torsten Sillke] Simplify tilde-expanded parameters
  * [tg, Torsten Sillke] Fix default PS1 for substring matches
  * [tg] Apply defer-builtin-with-arguments logic to realpath builtin
  * [tg] Rework string pooling (own vs. compiler?s) (LP#1580348)
  * [tg] Feature: print -A, prints arguments as characters
  * [tg, izabera] Replace <<< and >>> as ROL and ROR operators \ 
with their new ^
    < and ^> spelling as per this proposal
  * [tg, slagtc] Clear-to-EOL under tmux to work around its anti-feature
  * [tg, p120ph37] Remove support for using file descriptors with more than a
    single digit, in preparation for named file descriptors
  * [tg] Correct, but simplify (at the potential cost of more tty I/O than
    strictly necessary, though never redundant and (probably) not more than
    before when it was miscalculated), line clearing and redrawing
  * [slagtc, tg] Implement new evaluate-region editing command Esc+Ctrl-E
  * [tg] Prefer external rename utility over the recovery builtin
  * [tg] Remove redundant full-line redraws
  * [tg, Natureshadow] Fix errorlevel of ?.? (?dot? special builtin) when the
    sourced script does not run any commands, for POSIX compliance
  * [tg] Refactor op tokens and edchars to shave off some more bytes
  * [tg] Fix some bugs in the manpage and some occasional/minor code bugs
  * [tg, Brian Callahan] Mark tests requiring new perl as !need-pass
  * [tg, slagtc] Add $KSH_MATCH and, to make it usable, ${foo@/bar/baz}
  * [tg, Score_Under] Fix bogus patch from OpenBSD: only NULL the global source
    in unwind when actually reclaiming its Area
  * [izabera] Mention in the manpage that integer bases go up to 36
  * [Natureshadow] Fix /= operator broken during refactoring

R52c is a bugfix-only release:

  * [tg] Shave 200 bytes off .text by revisiting string pooling
  * [tg, J?rg] Fix manpage for ditroff on Schillix
  * [tg, wbx] Use sed 1q instead of unportable head(1)
  * [tg] Implement underrun debugging tool for area-based memory allocator
  * [tg] Fix history underrun when first interactive command is entered
  * [tg, bef0rd] Do not misinterpret ?${0/}? as ?${0//?, fixes segfault
  * [tg, St?phane Chazelas] Fix display problems with special parameters
  * [tg, St?phane Chazelas] Catch attempt to trim $* and $@ with ?, fixes
    segfault (Todd Miller did this in 2004 for ${x[*]} already, so just sync)
  * [Martijn Dekker] Fix ?command -p? with -Vv to behave as POSIX requires
  * [tg, jilles, Oleg Bulatov] Fix recusive parser with active heredocs
  * [tg] Flush even syntax-failing or interrupted commands to history
  * [tg, fmunozs] Fix invalid memory access for ?'\0'? in arithmetics
  * [tg] Explicitly reserve SIGEXIT and SIGERR for ksh
  * [tg, izabera] Catch missing here documents at EOF even under ?set -n?
  * [kre, tg] Document Austin#1015 handling (not considered a violation)
  * [tg, fmunozs] Fix buffer overread for empty nameref targets
  * [tg] Fix warnings pointed out by latest Debian gcc-snapshot
  * [tg, Martijn Dekker] Document upcoming set +o changes
  * [Martijn Dekker] Expand testsuite for command/whence

R52b is a strongly recommended bugfix-only release:

  * [tg] Recognise ksh93 compiled scripts and LZIP compressed files as binary
    (i.e. to not run as mksh plaintext script)
  * [tg] Document that we will implement locale tracking later
  * [tg] Add EEXIST to failback strerror(3)
  * [jilles] Make set -C; :>foo race-free
  * [tg] Don?t use unset in portable build script
  * [tg] Plug warning on GNU/kFreeBSD, GNU/Hurd
  * [tg] Document read -a resets the integer base
  * [J?rg] Fix manpage: time is not a builtin but a reserved word
  * [J?rg, tg] Make exit (and return) eat -1
  * [tg] parse ?$( (( ? ) ? ) ? )? correctly (LP#1532621), Jan Palus
  * [tg] reduce memory footprint by free(3)ing more aggressively
  * [tg] fix buffer overrun (LP#1533394), bugreport by izabera
  * [tg] correctly handle nested ADELIM parsing (LP#1453827), Teckids
  * [tg] permit ?read -A/-a arr[idx]? as long as only one element is read; fix
    corruption of array indic?s with this construct (LP#1533396), izabera
  * [tg] Sanitise OS-provided signal number in even more places
  * [tg] As requested by J?rg, be clear manpage advice is for mksh
  * [tg] Revert (as it was a regression) POSIX bugfix from R52/2005 related to
    accent gravis-style command substitution until POSIX decides either way
  * [tg] Handle export et al. after command (Austin#351)
  * [tg] Catch EPIPE in built-in cat and return as SIGPIPE (LP#1532621)
  * [tg] Fix errno in print/echo builtin; optimise that and unbksl
  * [tg] Update documentation, point out POSIX violation (Austin#1015)

R52 is a strongly recommended bugfix release:

  * [_0bitcount] Move moving external link from mksh(1) to the #ksh channel
    homepage linked therein
  * [tg] Make setenv ?set -u?-safe and fix when invoked with no args
  * [tg] Make ?typeset -f? output reentrant if name is a reserved word
  * [oksh] Zero-pad seconds in ?time? output to align columns
  * [tg] Check signals and errorlevels from OS to be within bounds
  * [komh, tg] Quote and document ?;? as PATH separator in some places
  * [oksh, tg] Simplify code to call afree() even if arg is NULL
  * [tg] Fix tree-printing and reentrancy of multiple here documents
  * [tg] Work around LP#1030581 by permitting exactly one space after
  * [tg, oksh] Code quality work, cleanups
  * [tg] New code for here documents/strings with several bugfixes
  * [tg] Stop using issetugid(2) for ?p checks, wrong tool for the job
  * [tg] Reintroduce some -o posix changes lost in 2005, plus fixes
  * [tg] Make ?source? into a built-in command
  * [tg] Drop ?stop? alias, lksh(1) functionality to auto-unalias
  * [tg] Fix \u0000 ignored in $'?' and print
  * [tg] Improve portability of Build.sh
  * [Jilles Tjoelker] Improve portability of testsuite
  * [tg] Fix tilde expansion for some substitutions (izabera, Chet, Geoff)
  * [tg] Improve reparsing of ((?) |?) as ( (?) |?)
  * [Martijn Dekker] Fix test(1) not returning evaluation errors
  * [tg] Fix ${*:+x} constructs (carstenh)
  * [tg] Make (( ? )) into a compound command (ormaaj)
  * [tg] Repair a few parameter substitution expansion mistakes

Log message:
Convert all occurrences (353 by my count) of

	MASTER_SITES= 	site1 \
			site2

style continuation lines to be simple repeated

	MASTER_SITES+= site1
	MASTER_SITES+= site2

lines. As previewed on tech-pkg. With thanks to rillig for fixing pkglint
accordingly.

Log message:
Bump PKGREVISION for perl-5.24.0 for everything mentioning perl.

Log message:
Add SHA512 digests for distfiles for shells category

Existing SHA1 digests verified, all found to be the same on the
machine holding the existing distfiles (morden).  Existing SHA1
digests retained for now as an audit trail.

Log message:
Update mksh to R51. From Changelog:

[tg] OpenBSD sync: handle integer base out of band like ksh93 does
[tg] Protect standard code (predefined aliases, internal code, aliases and \ 
functions in dot.mkshrc) from being overridden by aliases and, in some cases, \ 
shell functions (i.e. permit overriding but ignore it)
[tg] Implement GNU bash's enable for dot.mkshrc using magic aliases to redirect \ 
the builtins to external utilities; this differs from GNU bash in that enable \ 
takes precedence over functions
[tg] Move unaliasing an identifier when defining a POSIX-style function with the \ 
same name into lksh, as compatibility kludge
[tg] Korn shell style functions now have locally scoped shell options
[tg, iSKUNK] Change some ASCII-isms to be EBCDIC-aware or pluggable
[tg, Ypnose] Mention lksh build instructions on manpage and website
[tg] Overhaul signal handling; support new POSIX NSIG_MAX, add sysconf(_SC_NSIG) \ 
as a later TODO item
[tg] Fix signal bounds (1 <= signum < NSIG)
[tg] Improve manual pages, especially wrt. standards compliance
[tg, iSKUNK] Initial EBCDIC work for dot.mkshrc
[tg, iSKUNK] Add list of z/OS signals to Build.sh
[tg] Work around the sh(1) backslash-newline problem by moving the code \ 
triggering it out of *.opt and into the consumers
[colona] Bind another well-known ANSI Del key in the Emacs mode
[tg] Fix ${foo/*/x} pattern checks, spotted by izabera
[carstenh] Fix error output of cd function in dot.mkshrc
[tg] read partial returns in -N and timeout cases
[tg] Fix $LINENO inside PS1; spotted by carstenh
[tg] Ensure correct padding of at least 2 spaces in print_columns
[tg] Note issues with nested complex parameter expansions and follow-up bugfixes \ 
to expect
[OpenBSD] Some language fixes in documentation; comments
[tg] Reimplement multi-line command history (Debian #783978) + fixes
[Martijn Dekker] Fix command -v for "shell reserved words"
[tg] In dot.mkshrc make use of latest feature: local options
[tg] Fix ""$@ to emit a word
[tg] Change cat(1) hack to look first and not ignore builtin
[KO Myung-Hun] Begin porting mksh to OS/2
[komh, tg] Some generic minor bugfixes from OS/2 porting
[tg] Document mknod(8) isn’t normally part of mksh(1)
[tg] Quote arguments to : in build/test scripts as well
[tg] Add cat(1) hack for printf(1)-as-builtin: always prefer external
[tg] Explicitly use binary mode for any and all file I/O in stock mksh
[Ilya Zakharevich] Use termio, not termios(4), on OS/2
[tg] Set edchars to sane BSD defaults if any are NUL
[tg] Implement support for PC scancodes in Vi and Emacs editing mode
[komh] OS/2 uses ; as PATH separator plus support drive letters

Log message:
Update to R50f

Upstream changes:
R50f is a required security and bugfix release:

[tg] Add a patch marker for vendor patch versioning to mksh.1
[tg] SECURITY: make unset HISTFILE actually work
[tg] Document some more issues with the current history code
[tg] Remove some unused code
[tg] RCSID-only sync with OpenBSD, for bogus and irrelevant changes
[tg] Also disable field splitting for alias 'local=\typeset'
[tg] Fix read -n-1 to not be identical to read -N-1
[tg] Several fixes and improvements to lksh(1) and mksh(1) manpages
[tg] More code (int  size_t), comment and testsuite fixes
[tg] Make dot.mkshrc more robust (LP#1441853)
[tg] Fix issues with IFS='\' read, found by edualbus
[enh, tg] Fix integer overflows related to file descriptor parsing, found by \ 
Pawel Wylecial (LP#1440685); reduce memory usage for I/O redirs
[tg] Document in the manpage how to set ±U according to the current locale \ 
settings via LANG/LC_* parameters (cf. Debian #782225)
[igli, tg] Some code cleanup and restructuring
[tg, oksh] Handle number parsing and storing more carefully

R50e is a required bugfix release:
[tg] Add more tests detailing behaviour difference from GNU bash
[tg] Introduce a memory leak for x=<< fixing use of freed memory instead, \ 
bug tracked as LP#1380389 still live
[tg] Add x+=<< parallel to x=<<
[tg, ormaaj, jilles] POSIX "command" loses builtin special-ness
[tg] Fix LP#1381965 and LP#1381993 (more field splitting)
[jilles] Update location of FreeBSD testsuite for test(1)
[Martin Natano] Remove dead NULL elements from Emacs keybindings
[tg, Stéphane Chazelas, Geoff Clare] Change several testcases for $*/$@ \ 
expansion with/without quotes to expected-fail, with even more to come ☹
[tg] Fix miscalculating required memory for encoding the double-quoted parts of \ 
a here document or here string delimiter, leading to a buffer overflow; \ 
discovered by zacts from IRC
[RT] Rename a function conflicting with a MacRelix system header
[tg] Use size_t (and ssize_t) consistently, stop using ptrdiff_t; fixes some \ 
arithmetics and S/390 bugs
[tg] Remove old workarounds for Clang 3.2 scan-build
[tg] Remove all Clang/Coverity assertions, making room for new checks
[tg] Fix NSIG generation on Debian sid gcc-snapshot
[tg] Make a testcase not fail in a corner case
[tg] Fix issues detected by GCC’s new sanitisers: data type of a value to \ 
be shifted constantly must be unsigned (what not, in C…); shebang check \ 
array accesses are always unsigned char
[tg] Be even more explicit wrt. POSIX in the manpage
[tg] Fix shebang / file magic decoding
[tg] More int → bool conversion
[tg] Let Build.sh be run by GNU bash 1.12.1 (Slackware 1.01)
[Stéphane Chazelas, tg] Fix here string parsing issue
[tg] Point out more future changes in the manpage
[tg] Call setgid(2), setegid(2), setuid(2) before seteuid(2)
[tg] Fix spurious empty line after ENOENT “whence -v”, found by Ypnose
[tg] Optimise dot.mkshrc and modernise it a bit
[tg] Use MAXPATHLEN from <sys/param.h> for PATH_MAX fallback
[tg] Some code cleanup and warnings fixes
[tg] Add options -a argv0 and -c to exec
[jsg] Prevent use-after-free when hitting multiple errors unwinding
[tg] Fix use of $* and $@ in scalar context: within [[ … ]] and after case \ 
(spotted by Stéphane Chazelas) and in here documents (spotted by tg@); fix \ 
here document expansion
[tg] Unbreak when $@ shares double quotes with others
[tg] Fix set -x in PS4 expansion infinite loop