implement Filepat; include "sys.m";	sys: Sys; include "readdir.m";	rdir: Readdir; include "filepat.m"; expand(pat: string): list of string{	if(sys == nil){		sys = load Sys Sys->PATH;	}	if(rdir == nil){		rdir = load Readdir Readdir->PATH;	}	(nil, elem) := sys->tokenize(pat, "/");	if(elem == nil)		return filepat1(pat, nil, 0); 	files: list of string;	if(pat[0] == '/')		files = "/" :: nil; 	while(elem != nil){		files = filepat1(hd elem, files, tl elem!=nil);		if(files == nil)			break;		elem = tl elem;	}	return files;} filepat1(pat: string, files: list of string, mustbedir: int): list of string{	if(files == nil)		return filepatdir(pat, "", nil, mustbedir); 	# reverse list; will rebuild in forward order	r: list of string;	while(files != nil){		r = hd files :: r;		files = tl files;	}	files = r; 	nfiles: list of string = nil;	while(files != nil){		nfiles = filepatdir(pat, hd files, nfiles, mustbedir);		files = tl files;	}	return nfiles;} filepatdir(pat: string, dir: string, files: list of string, mustbedir: int): list of string{	if(pat=="." || pat=="..") {		if(dir=="/" || dir=="")			files = (dir + pat) :: files;		else			files = (dir + "/" + pat) :: files;		return files;	}	dirname := dir;	if(dir == "")		dirname = ".";	# sort into descending order means resulting list will ascend	(d, n) := rdir->init(dirname, rdir->NAME|rdir->DESCENDING|rdir->COMPACT);	if(d == nil)		return files; 	# suppress duplicates	for(i:=1; i<n; i++)		if(d[i-1].name == d[i].name){			d[i-1:] = d[i:];			n--;			i--;		} 	for(i=0; i<n; i++){		if(match(pat, d[i].name) && (mustbedir==0 || (d[i].mode&Sys->DMDIR))){			if(dir=="/" || dir=="")				files = (dir + d[i].name) :: files;			else				files = (dir + "/" + d[i].name) :: files;		}	}	return files;} match(pat, name: string): int{	n := 0;	p := 0;	while(p < len pat){		r := pat[p++];		case r{		'*' =>			pat = pat[p:];			if(len pat==0)				return 1;			for(; n<=len name; n++)				if(match(pat, name[n:]))					return 1;			return 0;		'[' =>			if(n == len name)				return 0;			s := name[n++];			matched := 0;			invert := 0;			first := 1;			esc: int;			while(p < len pat){				(p, r, esc) = char(pat, p);				if(first && !esc && r=='^'){					invert = 1;					first = 0;					continue;				}				first = 0;				if(!esc && r==']')					break;				lo, hi: int;				(p, lo, hi) = range(pat, p-1);				if(lo<=s && s<=hi)					matched = 1;			}			if(!(!esc && r==']') || invert==matched)				return 0;		'?' =>			if(n==len name)				return 0;			n++;		'\\' =>			if(n==len name || p==len pat || pat[p++]!=name[n++])				return 0;		* =>			if(n==len name || r!=name[n++])				return 0;		}	}	return n == len name;} # return character or range (a-z)range(pat: string, p: int): (int, int, int){	(q, lo, nil) := char(pat, p);	(q1, hi, esc) := char(pat, q);	if(!esc && hi=='-'){		(q1, hi, nil) = char(pat, q1);		return (q1, lo, hi);	}	return (q, lo, lo);} # return possibly backslash-escaped next characterchar(pat: string, p: int): (int, int, int){	if(p == len pat)		return (p, 0, -1);	r := pat[p++];	if(p==len pat || r!='\\')		return (p, r, 0);	return (p+1, pat[p], 1);}