diff --git a/FormalGrammars.cabal b/FormalGrammars.cabal
--- a/FormalGrammars.cabal
+++ b/FormalGrammars.cabal
@@ -1,5 +1,5 @@
 name:           FormalGrammars
-version:        0.2.1.0
+version:        0.2.1.1
 author:         Christian Hoener zu Siederdissen, 2013-2015
 copyright:      Christian Hoener zu Siederdissen, 2013-2015
 homepage:       https://github.com/choener/FormalGrammars
@@ -11,7 +11,7 @@
 build-type:     Simple
 stability:      experimental
 cabal-version:  >= 1.10.0
-tested-with:    GHC == 7.8.4, GHC == 7.10.1
+tested-with:    GHC == 7.8.4, GHC == 7.10.2
 synopsis:       (Context-free) grammars in formal language theory
 description:
                 <http://www.bioinf.uni-leipzig.de/Software/gADP/ generalized Algebraic Dynamic Programming>
@@ -69,23 +69,23 @@
 
 library
   build-depends: base                  >= 4.7     && < 4.9
-               , ADPfusion             >= 0.4.1   && < 0.4.2
-               , ansi-wl-pprint        == 0.6.7.*
-               , bytestring            == 0.10.*
+               , ADPfusion             >= 0.4.1   && < 0.5.1
+               , ansi-wl-pprint        >= 0.6.7   && < 0.6.8
+               , bytestring            >= 0.10    && < 0.11
                , containers
-               , data-default          == 0.5.*
-               , HaTeX                 == 3.16.*
-               , lens                  == 4.*
-               , mtl                   == 2.*
+               , data-default          >= 0.5     && < 0.6
+               , HaTeX                 >= 3.16    && < 3.17
+               , lens                  >= 4.0     && < 5.0
+               , mtl                   >= 2.0     && < 3.0
                , parsers               >= 0.12    && < 0.13
-               , PrimitiveArray        >= 0.6.0   && < 0.6.2
+               , PrimitiveArray        >= 0.6.0   && < 0.7.1
                , semigroups            >= 0.16    && < 0.17
                , template-haskell
-               , text                  == 1.*
+               , text                  >= 1.0     && < 1.3
                , transformers          >= 0.3     && < 0.5
-               , trifecta              == 1.5.*
-               , unordered-containers  == 0.2.*
-               , vector                == 0.10.*
+               , trifecta              >= 1.5     && < 1.6
+               , unordered-containers  >= 0.2     && < 0.3
+               , vector                >= 0.10    && < 0.12
   exposed-modules:
     FormalLanguage
     FormalLanguage.CFG
@@ -133,7 +133,7 @@
 executable GrammarPP
   build-depends: base
                , ansi-wl-pprint
-               , cmdargs          == 0.10.*
+               , cmdargs          >= 0.10   && < 0.11
                , FormalGrammars
   hs-source-dirs:
     src
diff --git a/FormalLanguage/CFG/Grammar/Util.hs b/FormalLanguage/CFG/Grammar/Util.hs
--- a/FormalLanguage/CFG/Grammar/Util.hs
+++ b/FormalLanguage/CFG/Grammar/Util.hs
@@ -134,3 +134,15 @@
   isll (Rule l _ []) = isSyntactic l
   isll (Rule l _ rs) = isSyntactic l && (allOf folded (not . isSyntactic) $ tail rs) -- at most one non-terminal
 
+isRightLinear :: Grammar -> Bool
+isRightLinear g = allOf folded isrl $ g^.rules where
+  isrl :: Rule -> Bool
+  isrl (Rule l _ []) = isSyntactic l
+  isrl (Rule l _ rs) = isSyntactic l && (allOf folded (not . isSyntactic) $ init rs)
+
+isLinear :: Grammar -> Bool
+isLinear g = allOf folded isl $ g^.rules where
+  isl :: Rule -> Bool
+  isl (Rule l _ []) = isSyntactic l
+  isl (Rule l _ rs) = isSyntactic l && (1 >= (length . filter isSyntactic $ rs))
+