Adding chr to the list of Postgresql functions.

src/Database/Esqueleto/PostgreSQL.hs

@@ -6,6 +6,7 @@
 module Database.Esqueleto.PostgreSQL
   ( arrayAgg
   , stringAgg
+  , chr
   ) where
 
 import Data.String (IsString)
@@ -32,3 +33,12 @@ stringAgg
   -> SqlExpr (Value s) -- ^ Delimiter.
   -> SqlExpr (Value s) -- ^ Concatenation.
 stringAgg expr delim = unsafeSqlFunction "string_agg" (expr, delim)
+
+
+-- | (@chr@) Translate the given integer to a character. (Note the result will
+-- depend on the character set of your database.)
+--
+-- /Since: 2.2.11/
+chr :: IsString s
+    => SqlExpr (Value Int) -> SqlExpr (Value s)
+chr = unsafeSqlFunction "chr"

test/Test.hs

@@ -1356,8 +1356,12 @@ main = do
             from $ \p -> do
             return (EP.stringAgg (p ^. PersonName) (val " "))
           liftIO $ L.sort (words ret) `shouldBe` L.sort (map personName people)
-#endif
 
+      it "chr looks sane" $
+        run $ do
+          [Value (ret :: String)] <- select $ return (EP.chr (val 65))
+          liftIO $ ret `shouldBe` "A"
+#endif
 
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