function eval_fmt(fmt/*:string*/, v/*:any*/, opts/*:any*/, flen/*:number*/) {
	if(typeof v == "number") v = normalize_xl_unsafe(v);
	var out = [], o = "", i = 0, c = "", lst='t', dt, j, cc;
	var hr='H';
	/* Tokenize */
	while(i < fmt.length) {
		switch((c = fmt.charAt(i))) {
			case 'G': /* General */
				if(!isgeneral(fmt, i)) throw new Error('unrecognized character ' + c + ' in ' +fmt);
				out[out.length] = {t:'G', v:'General'}; i+=7; break;
			case '"': /* Literal text */
				for(o="";(cc=fmt.charCodeAt(++i)) !== 34 && i < fmt.length;) o += String.fromCharCode(cc);
				out[out.length] = {t:'t', v:o}; ++i; break;
			case '\\': var w = fmt.charAt(++i), t = (w === "(" || w === ")") ? w : 't';
				out[out.length] = {t:t, v:w}; ++i; break;
			case '_': out[out.length] = {t:'t', v:" "}; i+=2; break;
			case '@': /* Text Placeholder */
				out[out.length] = {t:'T', v:v}; ++i; break;
			case 'B': case 'b':
				if(fmt.charAt(i+1) === "1" || fmt.charAt(i+1) === "2") {
					if(dt==null) { dt=parse_date_code(v, opts, fmt.charAt(i+1) === "2"); if(dt==null) return ""; }
					out[out.length] = {t:'X', v:fmt.substr(i,2)}; lst = c; i+=2; break;
				}
				/* falls through */
			case 'M': case 'D': case 'Y': case 'H': case 'S': case 'E':
				c = c.toLowerCase();
				/* falls through */
			case 'm': case 'd': case 'y': case 'h': case 's': case 'e': case 'g':
				if(v < 0) return "";
				if(dt==null) { dt=parse_date_code(v, opts); if(dt==null) return ""; }
				o = c; while(++i < fmt.length && fmt.charAt(i).toLowerCase() === c) o+=c;
				if(c === 'm' && lst.toLowerCase() === 'h') c = 'M';
				if(c === 'h') c = hr;
				out[out.length] = {t:c, v:o}; lst = c; break;
			case 'A': case 'a': case '上':
				var q={t:c, v:c};
				if(dt==null) dt=parse_date_code(v, opts);
				if(fmt.substr(i, 3).toUpperCase() === "A/P") { if(dt!=null) q.v = dt.H >= 12 ? fmt.charAt(i+2) : c; q.t = 'T'; hr='h';i+=3;}
				else if(fmt.substr(i,5).toUpperCase() === "AM/PM") { if(dt!=null) q.v = dt.H >= 12 ? "PM" : "AM"; q.t = 'T'; i+=5; hr='h'; }
				else if(fmt.substr(i,5).toUpperCase() === "上午/下午") { if(dt!=null) q.v = dt.H >= 12 ? "下午" : "上午"; q.t = 'T'; i+=5; hr='h'; }
				else { q.t = "t"; ++i; }
				if(dt==null && q.t === 'T') return "";
				out[out.length] = q; lst = c; break;
			case '[':
				o = c;
				while(fmt.charAt(i++) !== ']' && i < fmt.length) o += fmt.charAt(i);
				if(o.slice(-1) !== ']') throw 'unterminated "[" block: |' + o + '|';
				if(o.match(abstime)) {
					if(dt==null) { dt=parse_date_code(v, opts); if(dt==null) return ""; }
					out[out.length] = {t:'Z', v:o.toLowerCase()};
					lst = o.charAt(1);
				} else if(o.indexOf("$") > -1) {
					o = (o.match(/\$([^-\[\]]*)/)||[])[1]||"$";
					if(!fmt_is_date(fmt)) out[out.length] = {t:'t',v:o};
				}
				break;
			/* Numbers */
			case '.':
				if(dt != null) {
					o = c; while(++i < fmt.length && (c=fmt.charAt(i)) === "0") o += c;
					out[out.length] = {t:'s', v:o}; break;
				}
				/* falls through */
			case '0': case '#':
				o = c; while(++i < fmt.length && "0#?.,E+-%".indexOf(c=fmt.charAt(i)) > -1) o += c;
				out[out.length] = {t:'n', v:o}; break;
			case '?':
				o = c; while(fmt.charAt(++i) === c) o+=c;
				out[out.length] = {t:c, v:o}; lst = c; break;
			case '*': ++i; if(fmt.charAt(i) == ' ' || fmt.charAt(i) == '*') ++i; break; // **
			case '(': case ')': out[out.length] = {t:(flen===1?'t':c), v:c}; ++i; break;
			case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
				o = c; while(i < fmt.length && "0123456789".indexOf(fmt.charAt(++i)) > -1) o+=fmt.charAt(i);
				out[out.length] = {t:'D', v:o}; break;
			case ' ': out[out.length] = {t:c, v:c}; ++i; break;
			case '$': out[out.length] = {t:'t', v:'$'}; ++i; break;
			default:
				if(",$-+/():!^&'~{}<>=€acfijklopqrtuvwxzP".indexOf(c) === -1) throw new Error('unrecognized character ' + c + ' in ' + fmt);
				out[out.length] = {t:'t', v:c}; ++i; break;
		}
	}

	/* Scan for date/time parts */
	var bt = 0, ss0 = 0, ssm;
	for(i=out.length-1, lst='t'; i >= 0; --i) {
		switch(out[i].t) {
			case 'h': case 'H': out[i].t = hr; lst='h'; if(bt < 1) bt = 1; break;
			case 's':
				if((ssm=out[i].v.match(/\.0+$/))) { ss0=Math.max(ss0,ssm[0].length-1); bt = 4;}
				if(bt < 3) bt = 3;
			/* falls through */
			case 'd': case 'y': case 'e': lst=out[i].t; break;
			case 'M': lst=out[i].t; if(bt < 2) bt = 2; break;
			case 'm': if(lst === 's') { out[i].t = 'M'; if(bt < 2) bt = 2; } break;
			case 'X': /*if(out[i].v === "B2");*/
				break;
			case 'Z':
				if(bt < 1 && out[i].v.match(/[Hh]/)) bt = 1;
				if(bt < 2 && out[i].v.match(/[Mm]/)) bt = 2;
				if(bt < 3 && out[i].v.match(/[Ss]/)) bt = 3;
		}
	}

	/* time rounding depends on presence of minute / second / usec fields */
	var _dt;
	switch(bt) {
		case 0: break;
		case 1:
		case 2:
		case 3:
			if(dt.u >= 0.5) { dt.u = 0; ++dt.S; }
			if(dt.S >=  60) { dt.S = 0; ++dt.M; }
			if(dt.M >=  60) { dt.M = 0; ++dt.H; }
			if(dt.H >=  24) { dt.H = 0; ++dt.D; _dt = parse_date_code(dt.D); _dt.u = dt.u; _dt.S = dt.S; _dt.M = dt.M; _dt.H = dt.H; dt = _dt; }
			break;
		case 4:
			switch(ss0) {
				case 1: dt.u = Math.round(dt.u * 10)/10; break;
				case 2: dt.u = Math.round(dt.u * 100)/100; break;
				case 3: dt.u = Math.round(dt.u * 1000)/1000; break;
			}
			if(dt.u >=   1) { dt.u = 0; ++dt.S; }
			if(dt.S >=  60) { dt.S = 0; ++dt.M; }
			if(dt.M >=  60) { dt.M = 0; ++dt.H; }
			if(dt.H >=  24) { dt.H = 0; ++dt.D; _dt = parse_date_code(dt.D); _dt.u = dt.u; _dt.S = dt.S; _dt.M = dt.M; _dt.H = dt.H; dt = _dt; }
			break;
	}

	/* replace fields */
	var nstr = "", jj;
	for(i=0; i < out.length; ++i) {
		switch(out[i].t) {
			case 't': case 'T': case ' ': case 'D': break;
			case 'X': out[i].v = ""; out[i].t = ";"; break;
			case 'd': case 'm': case 'y': case 'h': case 'H': case 'M': case 's': case 'e': case 'b': case 'Z':
				/*::if(!dt) throw "unreachable"; */
				out[i].v = write_date(out[i].t.charCodeAt(0), out[i].v, dt, ss0);
				out[i].t = 't'; break;
			case 'n': case '?':
				jj = i+1;
				while(out[jj] != null && (
					(c=out[jj].t) === "?" || c === "D" ||
					((c === " " || c === "t") && out[jj+1] != null && (out[jj+1].t === '?' || out[jj+1].t === "t" && out[jj+1].v === '/')) ||
					(out[i].t === '(' && (c === ' ' || c === 'n' || c === ')')) ||
					(c === 't' && (out[jj].v === '/' || out[jj].v === ' ' && out[jj+1] != null && out[jj+1].t == '?'))
				)) {
					out[i].v += out[jj].v;
					out[jj] = {v:"", t:";"}; ++jj;
				}
				nstr += out[i].v;
				i = jj-1; break;
			case 'G': out[i].t = 't'; out[i].v = general_fmt(v,opts); break;
		}
	}
	var vv = "", myv, ostr;
	if(nstr.length > 0) {
		if(nstr.charCodeAt(0) == 40) /* '(' */ {
			myv = (v<0&&nstr.charCodeAt(0) === 45 ? -v : v);
			ostr = write_num('n', nstr, myv);
		} else {
			myv = (v<0 && flen > 1 ? -v : v);
			ostr = write_num('n', nstr, myv);
			if(myv < 0 && out[0] && out[0].t == 't') {
				ostr = ostr.substr(1);
				out[0].v = "-" + out[0].v;
			}
		}
		jj=ostr.length-1;
		var decpt = out.length;
		for(i=0; i < out.length; ++i) if(out[i] != null && out[i].t != 't' && out[i].v.indexOf(".") > -1) { decpt = i; break; }
		var lasti=out.length;
		if(decpt === out.length && ostr.indexOf("E") === -1) {
			for(i=out.length-1; i>= 0;--i) {
				if(out[i] == null || 'n?'.indexOf(out[i].t) === -1) continue;
				if(jj>=out[i].v.length-1) { jj -= out[i].v.length; out[i].v = ostr.substr(jj+1, out[i].v.length); }
				else if(jj < 0) out[i].v = "";
				else { out[i].v = ostr.substr(0, jj+1); jj = -1; }
				out[i].t = 't';
				lasti = i;
			}
			if(jj>=0 && lasti<out.length) out[lasti].v = ostr.substr(0,jj+1) + out[lasti].v;
		}
		else if(decpt !== out.length && ostr.indexOf("E") === -1) {
			jj = ostr.indexOf(".")-1;
			for(i=decpt; i>= 0; --i) {
				if(out[i] == null || 'n?'.indexOf(out[i].t) === -1) continue;
				j=out[i].v.indexOf(".")>-1&&i===decpt?out[i].v.indexOf(".")-1:out[i].v.length-1;
				vv = out[i].v.substr(j+1);
				for(; j>=0; --j) {
					if(jj>=0 && (out[i].v.charAt(j) === "0" || out[i].v.charAt(j) === "#")) vv = ostr.charAt(jj--) + vv;
				}
				out[i].v = vv;
				out[i].t = 't';
				lasti = i;
			}
			if(jj>=0 && lasti<out.length) out[lasti].v = ostr.substr(0,jj+1) + out[lasti].v;
			jj = ostr.indexOf(".")+1;
			for(i=decpt; i<out.length; ++i) {
				if(out[i] == null || ('n?('.indexOf(out[i].t) === -1 && i !== decpt)) continue;
				j=out[i].v.indexOf(".")>-1&&i===decpt?out[i].v.indexOf(".")+1:0;
				vv = out[i].v.substr(0,j);
				for(; j<out[i].v.length; ++j) {
					if(jj<ostr.length) vv += ostr.charAt(jj++);
				}
				out[i].v = vv;
				out[i].t = 't';
				lasti = i;
			}
		}
	}
	for(i=0; i<out.length; ++i) if(out[i] != null && 'n?'.indexOf(out[i].t)>-1) {
		myv = (flen >1 && v < 0 && i>0 && out[i-1].v === "-" ? -v:v);
		out[i].v = write_num(out[i].t, out[i].v, myv);
		out[i].t = 't';
	}
	var retval = "";
	for(i=0; i !== out.length; ++i) if(out[i] != null) retval += out[i].v;
	return retval;
}
SSF._eval = eval_fmt;