disallow double courly braces

as per yesterday's discussion about extended scripting variables

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/Uris.hs b/lib/Uris.hs
index e2d9a5f..24ddd93 100644
--- a/lib/Uris.hs
+++ b/lib/Uris.hs
@@ -18,6 +18,7 @@ import           Data.Either.Combinators (maybeToRight)
 import           Data.Map.Strict         (Map)
 import qualified Data.Map.Strict         as M
 import           Data.Text               (Text, pack)
+import qualified Data.Text as T
 import           GHC.Generics            (Generic)
 import           GHC.TypeLits            (KnownSymbol, symbolVal)
 import           Text.Regex.TDFA         ((=~))
@@ -66,7 +67,7 @@ data SubstError =
 applySubst :: KnownSymbol s
   => Proxy s -> SchemaSet -> Text -> Either SubstError Text
 applySubst s substs uri =  do
-  when (uri =~ "{{{.*}}}")
+  when (T.isInfixOf (pack "{{") uri || T.isInfixOf (pack "}}") uri)
    $ Left VarsDisallowed
   (schema, domain, rest) <- note NotALink $ parseUri uri