Add utility library for line scanning

util.py

@@ -0,0 +1,26 @@
+def raiseerror(cls,*args):
+	raise cls(*args)
+
+import re
+
+def matchinglines(lines,regex):
+	ret = []
+	for i in range(len(lines)):
+		match = re.match(regex,lines[i])
+		if match is not None:
+			ret.append(i)
+	return ret
+
+def walkback(lines,start,regex):
+	possible_lines = matchinglines(lines,regex)
+	possible_lines = [x for x in possible_lines if x<=start]
+	possible_lines.sort()
+	if len(possible_lines)>=1:
+		return possible_lines[-1]
+
+def walkup(lines,start,regex):
+	possible_lines = matchinglines(lines,regex)
+	possible_lines = [x for x in possible_lines if x>=start]
+	possible_lines.sort()
+	if len(possible_lines)>=1:
+		return possible_lines[0]