Merge pull request yesodweb#458 from ecognium/patch-1

Improved documentation for ||.
meteficha · Aug 23, 2015 · b5b9e3a · b5b9e3a
2 parents 6c304b6 + d2d07a5
commit b5b9e3a
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/persistent/Database/Persist.hs b/persistent/Database/Persist.hs
@@ -67,7 +67,12 @@ f /<-. a = Filter f (Right a) NotIn
 
 infixl 3 ||.
 (||.) :: forall v. [Filter v] -> [Filter v] -> [Filter v]
--- | the OR of two lists of filters
+-- | the OR of two lists of filters. For example: 
+-- selectList([PersonAge >. 25, PersonAge <. 30] ||. [PersonIncome >. 15000, PersonIncome <. 25000]) []
+-- will filter records where a person's age is between (25 and 30) OR a person's income is between (15,000 and 25000). 
+-- If you are looking for an &&. operator to do (A AND B AND (C OR D)) you can use the ++ operator instead as there is no &&. For example: 
+-- selectList([PersonAge >. 25, PersonAge <. 30] ++ ([PersonCategory ==. 1] ||.  [PersonCategory ==. 5])) []
+-- will filter records where a person's age is between (25 and 30) AND (person's category is either 1 or 5)  
 a ||. b = [FilterOr  [FilterAnd a, FilterAnd b]]
 
 listToJSON :: [PersistValue] -> T.Text