function choose_fmt(f/*:string*/, v/*:any*/) {
	var fmt = split_fmt(f);
	var l = fmt.length, lat = fmt[l-1].indexOf("@");
	if(l<4 && lat>-1) --l;
	if(fmt.length > 4) throw new Error("cannot find right format for |" + fmt.join("|") + "|");
	if(typeof v !== "number") return [4, fmt.length === 4 || lat>-1?fmt[fmt.length-1]:"@"];
	/* NOTE: most spreadsheet software do not support NaN or infinities */
	if(typeof v === "number" && !isFinite(v)) v = 0;
	switch(fmt.length) {
		case 1: fmt = lat>-1 ? ["General", "General", "General", fmt[0]] : [fmt[0], fmt[0], fmt[0], "@"]; break;
		case 2: fmt = lat>-1 ? [fmt[0], fmt[0], fmt[0], fmt[1]] : [fmt[0], fmt[1], fmt[0], "@"]; break;
		case 3: fmt = lat>-1 ? [fmt[0], fmt[1], fmt[0], fmt[2]] : [fmt[0], fmt[1], fmt[2], "@"]; break;
		case 4: break;
	}
	var ff = v > 0 ? fmt[0] : v < 0 ? fmt[1] : fmt[2];
	if(fmt[0].indexOf("[") === -1 && fmt[1].indexOf("[") === -1) return [l, ff];
	if(fmt[0].match(cfregex) != null || fmt[1].match(cfregex) != null) {
		var m1 = fmt[0].match(cfregex2);
		var m2 = fmt[1].match(cfregex2);
		return chkcond(v, m1) ? [l, fmt[0]] : chkcond(v, m2) ? [l, fmt[1]] : [l, fmt[m1 != null && m2 != null ? 2 : 1]];
	}
	return [l, ff];
}
function format(fmt/*:string|number*/,v/*:any*/,o/*:?any*/) {
	if(o == null) o = {};
	var sfmt = "";
	switch(typeof fmt) {
		case "string":
			if(fmt == "m/d/yy" && o.dateNF) sfmt = o.dateNF;
			else sfmt = fmt;
			break;
		case "number":
			if(fmt == 14 && o.dateNF) sfmt = o.dateNF;
			else sfmt = (o.table != null ? (o.table/*:any*/) : table_fmt)[fmt];
			if(sfmt == null) sfmt = (o.table && o.table[default_map[fmt]]) || table_fmt[default_map[fmt]];
			if(sfmt == null) sfmt = default_str[fmt] || "General";
			break;
	}
	if(isgeneral(sfmt,0)) return general_fmt(v, o);
	if(v instanceof Date) v = datenum_local(v, o.date1904);
	var f = choose_fmt(sfmt, v);
	if(isgeneral(f[1])) return general_fmt(v, o);
	if(v === true) v = "TRUE"; else if(v === false) v = "FALSE";
	else if(v === "" || v == null) return "";
	else if(isNaN(v) && f[1].indexOf("0") > -1) return "#VALUE!";
	else if(!isFinite(v) && f[1].indexOf("0") > -1) return "#DIV/0!";
	return eval_fmt(f[1], v, o, f[0]);
}