use std use "types"use "names"use "date"use "zoneinfo" pkg date =	type parsefail = union		`Doublefmt char		`Badsep (char, char)		`Badfmt char		`Badzone byte[:]		`Badname byte[:]		`Badchar		`Badampm		`Shortint		`Badint	;; 	/* date i/o */	const parsefmt	: (f : byte[:], s: byte[:]	-> std.result(instant, parsefail))	const parsefmtl	: (f : byte[:], s: byte[:]	-> std.result(instant, parsefail))	const parsefmtz	: (f : byte[:], s: byte[:], tz : byte[:]	-> std.result(instant, parsefail));; const UnixJulianDiff	= 719468 const parsefmt	= {f, s;	-> strparse(f, s, "", false)}const parsefmtl = {f, s;	-> strparse(f, s, "local", true)}const parsefmtz = {f, s, tz;	-> strparse(f, s, tz, true)} type parsedtz = union	`None	`Off duration	`Name byte[:];; const __init__ = {	var fail : parsefail	std.fmtinstall(std.typeof(fail), failfmt)} const strparse = {f, s, tz, replace	var d, err	var seen 	d = [.year = 0]	err = `std.None	seen = std.mkbs()	s = filldate(&d, f, s, seen, &err)	std.bsfree(seen) 	d.actual -= (d.tzoff : std.time)	match err	| `std.Some e:	-> `std.Err e	| `std.None:	/* no error, we're ok */	;; 	if replace		d = mkinstant(d.actual, tz)	;; 	-> `std.Ok d} const filldate = {d, f, s, seen, err	var fc, sc, z, am 	z = ""	am = `std.None	while f.len != 0		(fc, f) = std.charstep(f)		if fc == '%'			(fc, f) = std.charstep(f)			if std.bshas(seen, fc)				err# = `std.Some `Doublefmt fc				-> s			;;			std.bsput(seen, fc)			match fc			/* named things */			| 'a':	s = indexof(&d.day, s, _names.abbrevday[:], err)			| 'A':	s = indexof(&d.day, s, _names.fullday[:], err)			| 'b':	s = indexof(&d.mon, s, _names.abbrevmon[:], err)			| 'B':	s = indexof(&d.mon, s, _names.fullmon[:], err)			| 'c':	s = filldate(d, "%Y-%m-%d", s, seen, err)			| 'C':					s = intval(&d.year, s, 2, 2, err)				d.year += 1900			| 'd':	s = intval(&d.day, s, 2, 2, err)			| 'D':	s = filldate(d, "%m/%d/%y", s, seen, err)			| 'e':	s = intval(&d.day, s, 1, 2, err)			| 'F':	s = filldate(d, "%y-%m-%d", s, seen, err)			| 'h':	s = indexof(&d.day, s, _names.abbrevmon[:], err)			| 'H':	s = intval(&d.h, s, 1, 2, err)			| 'I':	s = intval(&d.h, s, 1, 2, err)			| 'k':	s = intval(&d.h, s, 1, 2, err)			| 'l':	s = intval(&d.h, s, 1, 2, err)			| 'm':	s = intval(&d.mon, s, 1, 2, err)			| 'M':	s = intval(&d.m, s, 1, 2, err)			| 'n':	s = matchstr(s, "\n", err)			| 'p':	s = matchampm(d, s, &am, err)			| 'P':	s = matchampm(d, s, &am, err)			| 'r':	s = filldate(d, "%H:%M:%S %P", s, seen, err) 			| 'R':	s = filldate(d, "%H:%M %P", s, seen, err)			| 's':	s = intval(&d.actual, s, 1, 64, err)			| 'S':	s = intval(&d.s, s, 1, 2, err)			| 't':	s = eatspace(s)			| 'u':	s = intval(&d.wday, s, 1, 1, err)			| 'x':	s = filldate(d, Datefmt, s, seen, err)			| 'X':	s = filldate(d, Timefmt, s, seen, err)			| 'y':	s = intval(&d.year, s, 1, 2, err)				d.year += 1900			| 'Y':					s = intval(&d.year, s, 1, 4, err)			| 'z':	s = tzoffset(&d.tzoff, s, err)			| 'Z':	(s, z) = tzstring(d, s, err)			| '%':	s = matchstr(s, "%", err)			| _:	std.fatal("unknown format character %c\n", fc)			;;		else			(sc, s) = std.charstep(s)			if std.isspace(fc) && std.isspace(sc)				s = eatspace(s)			elif sc != fc				err# = `std.Some `Badsep (fc, sc)				-> s			;;		;;		match err#		| `std.Some _:	-> s		| `std.None:		;;	;;	d.actual = recalc(d)	if z.len > 0		match _zoneinfo.findtzoff(z, d.actual)		| `std.Some o:	d.tzoff = o		| `std.None:	err# = `std.Some `Badzone z		;;	;; 	match am	| `std.None:	| `std.Some true:		d.h %= 12	| `std.Some false:		d.h %= 12		d.h += 12 	;;	-> s} const eatspace = {s	var c 	while std.isspace(std.decode(s))		(c, s) = std.charstep(s)	;;	-> s} const indexof = {dst, s, set, err	for var i = 0; i < set.len; i++		if s.len >= set[i].len && std.eq(s[:set[i].len], set[i])			dst# = i			-> s[set[i].len:]		;;	;;	err# = `std.Some `Badname s	dst# = 0	-> s} const tzoffset = {dst, s, err	var sgn	var tzoff 	if s.len < 1		err# = `std.Some `Badzone s		-> ""	;;	if std.eq(s[:1], "-")		sgn = -1	elif std.eq(s[:1], "+") 		sgn = 1	else		err# = `std.Some `Badzone s		-> s	;;	s = intval(&tzoff, s[1:], 2, 4, err) 	dst# = sgn * (tzoff / 100) * 3600 * 1_000_000 + (tzoff % 100) * 60 * 1_000_000	-> s} const tzstring = {d, s, err	var c, n 	n = 0	while true		c = std.decode(s[n:])		if c != '/' && !std.isalnum(c)			break		;;		n += std.charlen(c)	;;	if n < d._tzbuf.len		std.slcp(d._tzbuf[:n], s[:n])	else		err# = `std.Some `Badzone s[:n]	;;	-> (s[n:], s[:n])}  const matchstr = {s, str, err	if s.len <= str.len || !std.eq(s[:str.len], str)		err# = `std.Some `Badchar		-> s	;;	-> s[str.len:]} const matchampm = {d, s, am, err	if s.len < 2		err# = `std.Some `Badampm		-> s	;;	if std.eq(s[:2], "am") || std.eq(s[:2], "AM")		am# = `std.Some true		-> s[2:]	elif std.eq(s[:2], "pm") || std.eq(s[:2], "PM")		am# = `std.Some false		-> s[2:]	else		err# = `std.Some `Badampm		-> s	;;} generic intval = {dst : @a#, s : byte[:], min : @a, max : @a, err : std.option(parsefail)# -> byte[:] :: numeric,integral @a	var i, c, num 	num = s	for i = 0; i < min; i++		(c, s) = std.charstep(s)		if !std.isdigit(c)			err# = `std.Some `Shortint			-> s		;;	;; 	for i = min ; i < max; i++		c = std.decode(s)		if !std.isdigit(c)			break		;;		s = s[std.charlen(c):]	;; 	num = num[:i]	match std.intparse(num)	| `std.Some v:		dst# = v		-> s	| `std.None:		err# = `std.Some `Badint		-> s	;;} const failfmt = {sb, ap, opt	match std.vanext(ap)	| `Doublefmt chr:	std.sbfmt(sb, "saw duplicate format char '{}'", chr)	| `Badsep (e, f):	std.sbfmt(sb, "expected separator '{}', found '{}'", e, f)	| `Badfmt chr:		std.sbfmt(sb, "invalid format character '{}'", chr)	| `Badzone zone:	std.sbfmt(sb, "unknown time zone '{}'", zone)	| `Badname name:	std.sbfmt(sb, "could not find name '{}'", name)	| `Badchar:	std.sbfmt(sb, "unexpected character in parsed string")	| `Badampm:	std.sbfmt(sb, "invalid am/pm specifier")	| `Shortint:	std.sbfmt(sb, "integer had too few characters")	| `Badint:	std.sbfmt(sb, "integer could not be parsed")	;;}