@@ -0,0 +1,93 @@
+//  Copyright (c) 2016 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package nixattr
+
+import (
+	"unicode"
+)
+
+// States codify the classes that the parser recognizes.
+type State interface {
+	// is _sym_ the start character
+	StartSym(sym rune) bool
+
+	// is _sym_ a member of a class.
+	// peek, the next sym on the tape, can also be used to determine a class.
+	Member(sym rune, peek *rune) bool
+}
+
+func IsNonSplittingSymbolCase(sym rune) bool {
+	return unicode.IsPunct(sym) && sym != '.'
+}
+
+type LowerCaseState struct{}
+
+func (s *LowerCaseState) Member(sym rune, _ *rune) bool {
+	return unicode.IsLower(sym) || IsNonSplittingSymbolCase(sym) || unicode.IsNumber(sym)
+}
+
+func (s *LowerCaseState) StartSym(sym rune) bool {
+	return s.Member(sym, nil)
+}
+
+type UpperCaseState struct {
+	startedCollecting bool // denotes that the start character has been read
+	collectingUpper   bool // denotes if this is a class of all upper case letters
+}
+
+func (s *UpperCaseState) Member(sym rune, peek *rune) bool {
+	if !unicode.IsLower(sym) && !unicode.IsUpper(sym) {
+		return false
+	}
+
+	if peek != nil && unicode.IsUpper(sym) && unicode.IsLower(*peek) {
+		return false
+	}
+
+	if !s.startedCollecting {
+		// now we have to determine if upper-case letters are collected.
+		s.startedCollecting = true
+		s.collectingUpper = unicode.IsUpper(sym)
+
+		return true
+	}
+
+	return s.collectingUpper == unicode.IsUpper(sym)
+}
+
+func (s *UpperCaseState) StartSym(sym rune) bool {
+	return unicode.IsUpper(sym)
+}
+
+type NumberCaseState struct{}
+
+func (s *NumberCaseState) Member(sym rune, _ *rune) bool {
+	return unicode.IsNumber(sym) || IsNonSplittingSymbolCase(sym) || unicode.IsLower(sym)
+}
+
+func (s *NumberCaseState) StartSym(sym rune) bool {
+	return s.Member(sym, nil)
+}
+
+type NonAlphaNumericCaseState struct{}
+
+func (s *NonAlphaNumericCaseState) Member(sym rune, _ *rune) bool {
+	return !unicode.IsLower(sym) && !unicode.IsUpper(sym) && !unicode.IsNumber(sym) &&
+		!IsNonSplittingSymbolCase(sym)
+}
+
+func (s *NonAlphaNumericCaseState) StartSym(sym rune) bool {
+	return s.Member(sym, nil)
+}