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{	ns := len s;	n := len pre;	if(ns < n)		return 0;	for(k := 0; k < n; k++) {		if(pre[k] != s[k])			return 0;	}	return 1;} tolower(s: string): string{	r := s;	for(i := 0; i < len r; i++) {		c := r[i];		if(c >= int 'A' && c <= int 'Z')			r[i] = r[i] + (int 'a' - int 'A');	}	return r;} toupper(s: string): string{	r := s;	for(i := 0; i < len r; i++) {		c := r[i];		if(c >= int 'a' && c <= int 'z')			r[i] = r[i] - (int 'a' - int 'A');	}	return r;} tobig(s: string, base: int): (big, string){	if (s == nil || base < 0 || base > 36 || base == 1)		return (big 0, s); 	# skip possible leading white space	c: int;	for (i := 0; i < len s; i++) {		c = s[i];		if(c != ' ' && c != '\t' && c != '\n')			break;	} 	# skip possible sign character	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 (big 0, s);	} 	# parse number itself.	# perhaps this should check for overflow, and max out, as limbo op does?	start := i;	dig := '9';	if (base < 10)		dig = '0' + base - 1;	n := big 0;	for (; i < len s; i++) {		c = s[i];		if ('0' <= c && c <= dig)			n = (n * big base) + big(c - '0');		else if ('a' <= c && c < 'a' + base - 10)			n = (n * big base) + big(c - 'a' + 10);		else if ('A' <= c && c  < 'A' + base - 10)			n = (n * big base) + big(c - 'A' + 10);		else			break;	}	if (i == start)		return (big 0, s);	if (neg)		return (-n, s[i:]);	return (n, s[i:]);} toint(s: string, base: int): (int, string){	if (s == nil || base < 0 || base > 36 || base == 1)		return (0, s); 	# skip possible leading white space	c: int;	for (i := 0; i < len s; i++) {		c = s[i];		if(c != ' ' && c != '\t' && c != '\n')			break;	} 	# skip possible sign character	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, s);	} 	# parse number itself.	# perhaps this should check for overflow, and max out, as limbo op does?	start := i;	dig := '9';	if (base < 10)		dig = '0' + base - 1;	n := 0;	for (; i < len s; i++) {		c = s[i];		if ('0' <= c && c <= dig)			n = (n * base) + (c - '0');		else if ('a' <= c && c < 'a' + base - 10)			n = (n * base) + (c - 'a' + 10);		else if ('A' <= c && c  < 'A' + base - 10)			n = (n * base) + (c - 'A' + 10);		else			break;	}	if (i == start)		return (0, s);	if (neg)		return (-n, s[i:]);	return (n, 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;}