fix the pattern matching in unStr, unInt, unDouble

1 files changed, 3 insertions, 0 deletions

diff --git a/src/PGF/Expr.hs b/src/PGF/Expr.hs
index 78dbfb6a8..bddbc84d4 100644
--- a/src/PGF/Expr.hs
+++ b/src/PGF/Expr.hs
@@ -112,6 +112,7 @@ mkStr s = ELit (LStr s)
 -- | Decomposes an expression into string literal

 unStr :: Expr -> Maybe String

 unStr (ELit (LStr s)) = Just s

+unStr _               = Nothing

 

 -- | Constructs an expression from integer literal

 mkInt :: Integer -> Expr

@@ -120,6 +121,7 @@ mkInt i = ELit (LInt i)
 -- | Decomposes an expression into integer literal

 unInt :: Expr -> Maybe Integer

 unInt (ELit (LInt i)) = Just i

+unInt _               = Nothing

 

 -- | Constructs an expression from real number literal

 mkDouble :: Double -> Expr

@@ -128,6 +130,7 @@ mkDouble f = ELit (LFlt f)
 -- | Decomposes an expression into real number literal

 unDouble :: Expr -> Maybe Double

 unDouble (ELit (LFlt f)) = Just f

+unDouble _               = Nothing

 

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 -- Parsing