added mkMeta and isMeta in PGF

1 files changed, 10 insertions, 0 deletions

diff --git a/src/PGF/Expr.hs b/src/PGF/Expr.hs
index bddbc84d4..cf0cb79aa 100644
--- a/src/PGF/Expr.hs
+++ b/src/PGF/Expr.hs
@@ -5,6 +5,7 @@ module PGF.Expr(Tree, BindType(..), Expr(..), Literal(..), Patt(..), Equation(..
                 mkStr,    unStr,

                 mkInt,    unInt,

                 mkDouble, unDouble,

+                mkMeta,   isMeta,

 

                 normalForm,

 

@@ -132,6 +133,15 @@ unDouble :: Expr -> Maybe Double
 unDouble (ELit (LFlt f)) = Just f

 unDouble _               = Nothing

 

+-- | Constructs an expression which is meta variable

+mkMeta :: Expr

+mkMeta = EMeta 0

+

+-- | Checks whether an expression is a meta variable

+isMeta :: Expr -> Bool

+isMeta (EMeta _) = True

+isMeta _         = False

+

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 -- Parsing

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