--- a/upreckon/config.py	Thu Aug 11 20:44:23 2011 +0300
+++ b/upreckon/config.py	Thu Aug 11 23:20:52 2011 +0300
@@ -23,6 +23,7 @@
                     'maxcputime': None,
                     'maxwalltime': None,
                     'maxmemory': None,
+                    'match': '$%',
                     'dummies': (),
                     'testsexcluded': (),
                     'padtests': 0,

--- a/upreckon/files.py	Thu Aug 11 20:44:23 2011 +0300
+++ b/upreckon/files.py	Thu Aug 11 23:20:52 2011 +0300
@@ -5,10 +5,10 @@
 from __future__ import division, with_statement
 
 from .compat import *
-import contextlib, os, posixpath, shutil, sys
+import contextlib, itertools, os, posixpath, re, shutil, sys
 
 # You don't need to know about anything else.
-__all__ = 'File',
+__all__ = 'File', 'regexp'
 
 # In these two variables, use full stops no matter what os.extsep is;
 # all full stops will be converted to os.extsep on the fly
@@ -239,4 +239,26 @@
 		if self.archive:
 			self.archive.extract(self.real_path, target)
 		else:
-			shutil.copy(self.real_path, target)
\ No newline at end of file
+			shutil.copy(self.real_path, target)
+
+def regexp(pattern, hastests=False, droplast=False):
+	# FIXME: add test archives
+	if not pattern:
+		yield os.curdir, ''
+		return
+	dirname, basename = posixpath.split(pattern)
+	if hastests:
+		dirnames = regexp(dirname, True)
+	else:
+		dirnames = itertools.chain(regexp(dirname), regexp(posixpath.join(dirname, 'tests'), True, True))
+	reobj = re.compile(pattern + '$', re.UNICODE)
+	for dirname, vdirname in dirnames:
+		try:
+			names = os.listdir(dirname)
+		except OSError:
+			continue
+		for name in names:
+			path = os.path.join(dirname, name)
+			vpath = posixpath.join(vdirname, name)
+			if re.match(reobj, vpath):
+				yield path, vpath if not droplast else vdirname

--- a/upreckon/problem.py	Thu Aug 11 20:44:23 2011 +0300
+++ b/upreckon/problem.py	Thu Aug 11 23:20:52 2011 +0300
@@ -4,7 +4,7 @@
 
 from .compat import *
 from .exceptions import *
-from . import config, testcases
+from . import config, files, testcases
 from __main__ import options
 
 import os, re, sys
@@ -248,6 +248,21 @@
 	except Exception:
 		prob.config.tests = tuple(prob.config.tests)
 	
+	if prob.config.match == 're':
+		if not prob.config.usegroups:
+			prob.config.tests = prob.config.tests, None
+		elif isinstance(prob.config.tests, basestring):
+			prob.config.tests = prob.config.tests, 2
+		parts = tuple(map(re.escape, prob.config.dummyinname.split('$')))
+		probname = re.escape(prob.name) + '/' if prob.name != os.curdir else ''
+		path = '%s%s(%s)' % (probname, parts[0], prob.config.dummies)
+		path += r'\1'.join(parts[1:])
+		prob.config.dummies = regexp(path, None)
+		parts = tuple(map(re.escape, prob.config.testcaseinname.split('$')))
+		path = '%s%s(%s)' % (probname, parts[0], prob.config.tests[0])
+		path += r'\1'.join(parts[1:])
+		prob.config.tests = regexp(path, prob.config.tests[1])
+	
 	if options.legacy:
 		prob.config.usegroups = False
 		newtests = []
@@ -335,3 +350,24 @@
 			s = str(i).zfill(prob.config.padtests)
 			if (yield _types[prob.config.kind](prob, s, False, getpoints(i, j))):
 				yield
+
+def regexp(pattern, group):
+	reobj = re.compile(pattern, re.UNICODE)
+	if not group:
+		ids = []
+		for path, vpath in files.regexp(pattern):
+			ids.append(re.match(reobj, vpath).group(1))
+		return natsorted(ids)
+	else:
+		ids = {}
+		for path, vpath in files.regexp(pattern):
+			m = re.match(reobj, vpath)
+			g = m.group(group)
+			ids.setdefault(g, [])
+			ids[g].append(m.group(1))
+		for g in ids:
+			ids[g] = natsorted(ids[g])
+		return [ids[g] for g in natsorted(keys(ids))]
+
+def natsorted(l):
+	return sorted(l, key=lambda s: [int(t) if t.isdigit() else t for t in re.split('(\d+)', s)])