shithub: mc

ref: 2c4eeb399845785a1dc317e4f2e3cb3c3c7c5370
dir: /lib/date/fmt.myr/

use std

use "types"
use "names"

pkg date = 
	const sbfmt	: (sb : std.strbuf#, args : std.valist#, opt : (byte[:], byte[:])[:] -> void)
;;

const __init__ = {
	var d : instant

	std.fmtinstall(std.typeof(d), sbfmt, [
		("D", false),
		("d", false),
		("t", false),
		("f", true),
	][:])
}

/* Always formats in proleptic Gregorian format */
const sbfmt = {sb, ap, opts
	var d : instant
	var fmt

	d = std.vanext(ap)
	fmt = Datetimefmt;
	for o in opts
		match o
		| ("d", ""):	fmt = Datefmt
		| ("t", ""):	fmt = Timefmt
		| ("D", ""):	fmt = Datetimefmt
		| ("f", opt):	fmt = opt
		| _:	std.fatal("unknown option")
		;;
	;;
	datefmt(sb, fmt, d)
}

const datefmt = {sb, fmt, d
	var c
	while fmt.len != 0
		(c, fmt) = std.strstep(fmt)
		if c == '%'
			(c, fmt) = std.strstep(fmt)
			match c
			| 'a':	std.sbfmt(sb, "{}", _names.abbrevday[d.day])
			| 'A':	std.sbfmt(sb, "{}", _names.fullday[d.day])
			| 'b':	std.sbfmt(sb, "{}", _names.abbrevmon[d.mon])
			| 'B':	std.sbfmt(sb, "{}", _names.fullmon[d.mon])
			| 'c':	datefmt(sb, "%Y-%m-%d %H:%M:%S %z", d)
			| 'C':	std.sbfmt(sb, "{p=0,w=2}", d.year % 100)
			| 'd':	std.sbfmt(sb, "{p=0,w=2}", d.day)
			| 'D':	datefmt(sb, "%m/%d/%y (wtf america)", d)
			| 'e':	std.sbfmt(sb, "{w=2}", d.day)
			| 'F':	datefmt(sb, "%Y-%m-%d", d)
			/*
			| 'G':	s = std.sbfmt(sb, ...?
			| 'g':
			*/
			| 'h':	std.sbfmt(sb, "{}", _names.abbrevmon[d.mon])
			| 'H':	std.sbfmt(sb, "{p=0,w=2}", d.h)
			| 'I':	std.sbfmt(sb, "{p=0,w=2}", d.h % 12)
			| 'j':	std.sbfmt(sb, "year day... unimplemented.")
			| 'k':	std.sbfmt(sb, "{}", d.h)
			| 'l':	std.sbfmt(sb, "{}", d.h % 12)
			| 'm':	std.sbfmt(sb, "{}", d.mon)
			| 'M':	std.sbfmt(sb, "{p=0,w=2}", d.m)
			| 'n':	std.sbfmt(sb, "\n")
			| 'O':	std.sbfmt(sb, "unsupported %O")
			| 'p':	std.sbfmt(sb, "{}", ["AM", "PM"][d.h/12])
			| 'P':	std.sbfmt(sb, "{}", ["am", "pm"][d.h/12])
			| 'r':	datefmt(sb, "%I:%M:%S %P", d) 
			| 'R':	datefmt(sb, "%H:%M", d)
			| 's':	std.sbfmt(sb, "{}", d.actual / 1_000_000)
			| 'S':	std.sbfmt(sb, "{p=0,w=2}", d.s)
			| 'T':	datefmt(sb, "%H:%M:%S", d)
			| 't':	std.sbfmt(sb, "\t")
			| 'u':	std.sbfmt(sb, "{}", d.wday)
			| 'U':	std.sbfmt(sb, "week number... unimplemented.")
			| 'x':	datefmt(sb, Datefmt, d)
			| 'X':	datefmt(sb, Timefmt, d)
			| 'y':	std.sbfmt(sb, "{}", d.year % 100)
			| 'Y':	std.sbfmt(sb, "{}", d.year)
			| 'z':	timezone(sb, d.tzoff)
			| 'Z':	std.sbfmt(sb, "{}", d.tzname)
			| '%':	std.sbfmt(sb, "%")
			| _:	std.fatal("unknown format character {}\n", c)
			;;
		else
			std.sbfmt(sb, "{}", c)
		;;
	;;
}

const timezone = {sb, off
	var h, m
	var sep

	sep = "+"
	if off < 0
		off = -off
		sep = "-"
	;;
	off /= 1_000_000
	h = off / 3600
	m = off % 3600
	-> std.sbfmt(sb, "{}{p=0,w=2}{p=0,w=2}", sep, h, m)
}