diff --git a/glabrous.cabal b/glabrous.cabal
--- a/glabrous.cabal
+++ b/glabrous.cabal
@@ -1,5 +1,5 @@
 name:                glabrous
-version:             0.3.6
+version:             0.4.0
 synopsis:            A template DSL library
 description:         A minimalistic, Mustache-like syntax, truly logic-less,
                      pure Text template DSL library
diff --git a/src/Text/Glabrous.hs b/src/Text/Glabrous.hs
--- a/src/Text/Glabrous.hs
+++ b/src/Text/Glabrous.hs
@@ -28,6 +28,7 @@
   , toFinalText
   , compress
   , writeTemplateFile
+  , insert
 
   -- * 'Context'
   , Context (..)
@@ -44,6 +45,7 @@
   , variablesOf
   , isSet
   , unsetContext
+  , join
 
   -- ** JSON 'Context' file
   , readContextFile
@@ -59,7 +61,7 @@
 
   ) where
 
-import           Control.Monad
+import           Control.Monad            (guard)
 import           Data.Aeson
 import           Data.Aeson.Encode.Pretty (encodePretty)
 import qualified Data.ByteString.Lazy     as L
@@ -107,7 +109,7 @@
   where
     go _ts vs =
       case uncons _ts of
-        Just ((k,v),ts') -> go ts' $ H.insert k v vs
+        Just ((k,v),ts') -> go ts' (H.insert k v vs)
         Nothing          -> Context { variables = vs }
 
 -- | Delete variables from a 'Context' by these names.
@@ -120,7 +122,7 @@
   where
     go _ts vs =
       case uncons _ts of
-        Just (k,ts') -> go ts' $ H.delete k vs
+        Just (k,ts') -> go ts' (H.delete k vs)
         Nothing      -> Context { variables = vs }
 
 -- | Build a 'Context' from a list of 'Tag's and replacement 'T.Text's.
@@ -146,6 +148,17 @@
 readContextFile :: FilePath -> IO (Maybe Context)
 readContextFile f = decode <$> L.readFile f
 
+-- | Join two 'Context's if they don't share variables
+-- name, or get the intersection 'Context' out of them.
+join :: Context
+     -> Context
+     -> Either Context Context
+join c c' = do
+  let i = H.intersection (variables c) (variables c')
+  if i == H.empty
+    then Right Context { variables = H.union (variables c) (variables c') }
+    else Left Context { variables = i }
+
 -- | Write a 'Context' to a file.
 --
 -- @
@@ -156,7 +169,7 @@
 -- @
 --
 writeContextFile :: FilePath -> Context -> IO ()
-writeContextFile f c = L.writeFile f $ encodePretty c
+writeContextFile f c = L.writeFile f (encodePretty c)
 
 -- | Based on the given 'Context', write a JSON
 -- 'Context' file with all its variables empty.
@@ -169,7 +182,7 @@
 -- @
 --
 initContextFile :: FilePath -> Context -> IO ()
-initContextFile f Context {..} = L.writeFile f $
+initContextFile f Context{..} = L.writeFile f $
   encodePretty Context { variables = H.map (const T.empty) variables }
 
 -- | Build 'Just' a (sub)'Context' made of unset variables
@@ -200,13 +213,29 @@
 
 -- | Write a 'Template' to a file.
 writeTemplateFile :: FilePath -> Template -> IO ()
-writeTemplateFile f t = I.writeFile f $ toText t
+writeTemplateFile f t = I.writeFile f (toText t)
 
+-- | get 'Just' a new 'Template' by inserting a 'Template'
+-- into another one by replacing the 'Tag' named, or 'Nothing'.
+insert :: Template       -- ^ The Template to insert in
+       -> T.Text         -- ^ The Tag name to be replaced
+       -> Template       -- ^ The Template to be inserted
+       -> Maybe Template -- ^ Just the new Template, or Nothing
+insert te tn te' = do
+  guard (Tag tn `elem` content te)
+  return Template { content = foldl trans [] (content te) }
+  where
+    trans o t@(Tag tn') =
+      if tn' == tn
+        then o ++ content te'
+        else o ++ [t]
+    trans o l = o ++ [l]
+
 -- | Output the content of the given 'Template'
 -- as it is, with its 'Tag's, if they exist.
 toText :: Template -> T.Text
 toText Template{..} =
-  T.concat $ trans <$> content
+  T.concat (trans <$> content)
   where
     trans (Literal c) = c
     trans (Tag k)     = T.concat ["{{",k,"}}"]
@@ -281,7 +310,7 @@
 partialProcess' :: Template -> Context -> G.Result
 partialProcess' t c@Context{..} =
   case foldl trans ([],[]) (content t) of
-    (f,[]) -> Final $ toTextWithContext (const T.empty) c f
+    (f,[]) -> Final (toTextWithContext (const T.empty) c f)
     (p,p') -> G.Partial Template { content = p } (fromTagsList p')
   where
     trans (!c',!ts) t' =