implement String; include "string.m"; splitl(s: string, cl: string): (string, string){	n := len s;	for(j := 0; j < n; j++) {		if(in(s[j], cl))			return (s[0:j], s[j:n]);	}	return (s,"");} splitr(s: string, cl: string): (string, string){	n := len s;	for(j := n-1; j >= 0; j--) {		if(in(s[j], cl))			return (s[0:j+1], s[j+1:n]);	}	return ("",s);} drop(s: string, cl: string): string{	n := len s;	for(j := 0; j < n; j++) {		if(!in(s[j], cl))			return (s[j:n]);	}	return "";} take(s: string, cl: string): string{	n := len s;	for(j := 0; j < n; j++) {		if(!in(s[j], cl))			return (s[0:j]);	}	return s;} in(c: int, s: string): int{	n := len s;	if(n == 0)		return 0;	ans := 0;	negate := 0;	if(s[0] == '^') {		negate = 1;		s = s[1:];		n--;	}	for(i := 0; i < n; i++) {		if(s[i] == '-' && i > 0 && i < n-1)  {			if(c >= s[i-1] && c <= s[i+1]) {				ans = 1;				break;			}			i++;		}		else		if(c == s[i]) {			ans = 1;			break;		}	}	if(negate)		ans = !ans;	return ans;} splitstrl(s: string, t: string): (string, string){	n := len s;	nt := len t;	if(nt == 0)		return ("", s);	c0 := t[0];    mainloop:	for(j := 0; j <= n-nt; j++) {		if(s[j] == c0) {			for(k := 1; k < nt; k++)				if(s[j+k] != t[k])					continue mainloop;			return(s[0:j], s[j:n]);		}	}	return (s,"");} splitstrr(s: string, t: string): (string, string){	n := len s;	nt := len t;	if(nt == 0)		return (s, "");	c0 := t[0];    mainloop:	for(j := n-nt; j >= 0; j--) {		if(s[j] == c0) {			for(k := 1; k < nt; k++)				if(s[j+k] != t[k])					continue mainloop;			return(s[0:j+nt], s[j+nt:n]);		}	}	return ("",s);} prefix(pre: string, s: string): int{	if(len s < len pre)		return 0;	for(k := 0; k < len pre; k++)		if(pre[k] != s[k])			return 0;	return 1;} tolower(s: string): string{	for(i := 0; i < len s; i++) {		c := s[i];		if(c >= 'A' && c <= 'Z')			s[i] += 'a' - 'A';	}	return s;} toupper(s: string): string{	for(i := 0; i < len s; i++) {		c := s[i];		if(c >= 'a' && c <= 'z')			s[i] += 'A' - 'a';	}	return s;} startnum(s: string, base: int): (int, int, int){	if(s == nil || base != 0 && (base < 2 || base > 36))		return (0, 0, 0); 	# skip possible leading white space	c := ' ';	for (i := 0; i < len s; i++) {		c = s[i];		if(c != ' ' && c != '\t' && c != '\n')			break;	} 	# optional sign	neg := 0;	if(c == '-' || c == '+') {		if(c == '-')			neg = 1;		i++;	} 	if(base == 0) {		# parse possible leading base designator		start := i;		base = -1;		for (; i < start+3 && i < len s; i++) {			c = s[i];			if (c == 'r' && i > start) {				base = int s[start:i];				i++;				break;			} else if (c < '0' || c > '9')				break;		}		if (base == -1) {			i = start;			base = 10;		} else if (base == 0 || base > 36)			return (0, 0, i);	}	if(i >= len s)		return (0, 0, 0); 	return (base, neg, i);} tobig(s: string, base: int): (big, string){	neg, i: int; 	(base, neg, i) = startnum(s, base);	if(base == 0)		return (big 0, s); 	# parse number itself.	# probably this should check for overflow, and max out, as limbo op does?	start := i;	n := big 0;	for (; i < len s; i++) {		if((d := digit(s[i], base)) < 0)			break;		n = n*big base + big d;	}	if (i == start)		return (big 0, s);	if (neg)		return (-n, s[i:]);	return (n, s[i:]);} toint(s: string, base: int): (int, string){	neg, i: int; 	(base, neg, i) = startnum(s, base);	if(base == 0)		return (0, s); 	# parse number itself.	# probably this should check for overflow, and max out, as limbo op does?	start := i;	n := 0;	for (; i < len s; i++){		if((d := digit(s[i], base)) < 0)			break;		n = n*base + d;	}	if (i == start)		return (0, s);	if (neg)		return (-n, s[i:]);	return (n, s[i:]);} digit(c: int, base: int): int{	if ('0' <= c && c <= '0' + base - 1)		return c-'0';	else if ('a' <= c && c < 'a' + base - 10)		return (c - 'a' + 10);	else if ('A' <= c && c  < 'A' + base - 10)		return (c - 'A' + 10);	else		return -1;	} rpow(x: real, n: int): real{	inv := 0;	if(n < 0){		n = -n;		inv = 1;	}	r := 1.0;	for(;;){		if(n&1)			r *= x;		if((n >>= 1) == 0)			break;		x *= x;	}	if(inv)		r = 1.0/r;	return r;} match(p: string, s: string, i: int): int{	if(i+len p > len s)		return 0;	for(j := 0; j < len p; j++){		c := s[i++];		if(c >= 'A' && c <= 'Z')			c += 'a'-'A';		if(p[j] != c)			return 0;	}	return 1;} toreal(s: string, base: int): (real, string){	neg, i: int; 	(base, neg, i) = startnum(s, base);	if(base == 0)		return (0.0, s); 	c := s[i];	if((c == 'i' || c == 'I') && match("infinity", s, i))		return (real s, s[i+8:]);	if((c == 'n' || c == 'N') && match("nan", s, i))		return (real s, s[i+3:]); 	if(digit(c, base) < 0)		return (0.0, s); 	num := 0.0;	for(; i < len s && (d := digit(s[i], base)) >= 0; i++)		num = num*real base + real d;	dig := 0;	# digits in fraction	if(i < len s && s[i] == '.'){		i++;		for(; i < len s && (d = digit(s[i], base)) >= 0; i++){			num = num*real base + real d;			dig++;		}	}	exp := 0;	eneg := 0;	if(i < len s && ((c = s[i]) == 'e' || c == 'E')){		start := i;	# might still be badly formed		i++;		if(i < len s && ((c = s[i]) == '-' || c == '+')){			i++;			if(c == '-'){				dig = -dig;				eneg = 1;			}		}		if(i < len s && s[i] >= '0' && s[i] <= '9'){	# exponents are always decimal			for(; i < len s && (d = digit(s[i], 10)) >= 0; i++)				exp = exp*base + d;		}else			i = start;	}	if(base == 10)		return (real s[0: i], s[i:]);	# conversion can be more accurate	exp -= dig;	if(exp < 0){		exp = -exp;		eneg = !eneg;	}	if(exp < 0 || exp > 19999)		exp = 19999;	# huge but otherwise arbitrary limit	dem := rpow(real base, exp);	if(eneg)		num /= dem;	else		num *= dem;	if(neg)		return  (-num,s[i:]);	return (num, s[i:]);} append(s: string, l: list of string): list of string{	t:	list of string; 	# Reverse l, prepend s, and reverse result.	while (l != nil) {		t = hd l :: t;		l = tl l;	}	t = s :: t;	do {		l = hd t :: l;		t = tl t;	} while (t != nil);	return l;} quoted(argv: list of string): string{	return quotedc(argv, nil);} quotedc(argv: list of string, cl: string): string{	s := "";	while(argv != nil){		arg := hd argv;		for(i := 0; i < len arg; i++){			c := arg[i];			if(c == ' ' || c == '\t' || c == '\n' || c == '\'' || in(c, cl))				break;		}		if(i < len arg || arg == nil){			s += "'" + arg[0:i];			for(; i < len arg; i++){				if (arg[i] == '\'')					s[len s] = '\'';				s[len s] = arg[i];			}			s[len s] = '\'';		}else			s += arg;		if(tl argv != nil)			s[len s] = ' ';		argv = tl argv;	}	return s;} unquoted(s: string): list of string{	args: list of string;	word: string;	inquote := 0;	for(j := len s; j > 0;){		c := s[j-1];		if(c == ' ' || c == '\t' || c == '\n'){			j--;			continue;		}		for(i := j-1; i >= 0 && ((c = s[i]) != ' ' && c != '\t' && c != '\n' || inquote); i--){	# collect word			if(c == '\''){				word = s[i+1:j] + word;				j = i;				if(!inquote || i == 0 || s[i-1] != '\'')					inquote = !inquote;				else					i--;			}		}		args = (s[i+1:j]+word) :: args;		word = nil;		j = i;	}	# if quotes were unbalanced, balance them and try again.	if(inquote)		return unquoted(s + "'");	return args;}