3 files changed, 76 insertions, 8 deletions
diff --git a/src/Store/Query/Parser.hs b/src/Store/Query/Parser.hs
index 99ddc79..ce2a4dd 100644
--- a/src/Store/Query/Parser.hs
+++ b/src/Store/Query/Parser.hs
@@ -15,9 +15,11 @@ import Data.Vector qualified as V
 import Data.Void (Void)
 import Store.Exception (ParseError (ParseError))
 import Store.Query.Type
+import System.IO.Unsafe (unsafePerformIO)
 import Text.Megaparsec qualified as P
 import Text.Megaparsec.Char qualified as P
 import Text.Megaparsec.Char.Lexer qualified as P
+import Text.Regex.PCRE.String
 
 instance IsString Query where
   fromString =
@@ -51,7 +53,11 @@ instance IsString Query where
               w <- P.optional do
                 where_
                 whereClause
-              pure $ Select fs c js es w,
+              l <- P.optional do
+                limitClause
+              o <- P.optional do
+                offsetClause
+              pure $ Select fs c js es w l o,
             do
               update
               c <- collection
@@ -78,11 +84,14 @@ instance IsString Query where
       comma = void $ lexeme (P.string ",")
       embed = void $ lexeme (P.string "EMBED")
       eq = void $ lexeme (P.string "==")
+      match = void $ lexeme (P.string "=~")
       from = void $ lexeme (P.string "FROM")
       on = void $ lexeme (P.string "ON")
       or = void $ lexeme (P.string "OR")
       select = void $ lexeme (P.string "SELECT")
       where_ = void $ lexeme (P.string "WHERE")
+      offset_ = void $ lexeme (P.string "OFFSET")
+      limit_ = void $ lexeme (P.string "LIMIT")
 
       collection = lexeme $ P.takeWhile1P (Just "collection") (not . isSpace)
 
@@ -113,11 +122,30 @@ instance IsString Query where
             Where <$> comparison
           ]
 
-      comparison = do
-        a <- P.choice [Left <$> value, Right <$> field]
-        eq
-        b <- P.choice [Left <$> value, Right <$> field]
-        pure $ Eq a b
+      comparison =
+        P.choice
+          ( map
+              P.try
+              [ do
+                  a <- P.choice [Left <$> value, Right <$> field]
+                  eq
+                  b <- P.choice [Left <$> value, Right <$> field]
+                  pure $ Eq a b,
+                do
+                  a <- P.choice [Left <$> value, Right <$> field]
+                  match
+                  b <- regex
+                  pure $ Regex a b
+              ]
+          )
+
+      offsetClause = do
+        offset_
+        Offset <$> lexeme P.decimal
+
+      limitClause = do
+        limit_
+        Limit <$> lexeme P.decimal
 
       fieldSelector =
         lexeme $
@@ -230,6 +258,21 @@ instance IsString Query where
       fieldPart :: P.Parsec Void String String
       fieldPart = P.takeWhile1P Nothing (\c -> not (isSpace c) && c /= ',' && c /= '.')
 
+      regex = lexeme do
+        ( unsafePerformIO . compile compBlank execBlank
+            <$> between (Just (P.string "\\")) (P.string "/") (P.string "/")
+          )
+          >>= either (\e -> error ("regex failed to compile: " <> show e)) pure
+
+      between (Just e) start end = start >> go
+        where
+          go =
+            P.choice
+              [ e >> (:) <$> P.anySingle <*> go,
+                P.try ((const "") <$> end),
+                (:) <$> P.anySingle <*> go
+              ]
+
       joinType :: P.Parsec Void String JoinType
       joinType =
         P.choice
diff --git a/src/Store/Query/Printer.hs b/src/Store/Query/Printer.hs
index cff543f..ecde378 100644
--- a/src/Store/Query/Printer.hs
+++ b/src/Store/Query/Printer.hs
@@ -26,7 +26,7 @@ instance Show Query where
         Just "INTO",
         Just (showCollection c)
       ]
-  show (Select fs c js es w) =
+  show (Select fs c js es w l o) =
     intercalate " " . catMaybes $
       [ Just "SELECT",
         Just (showFieldSelector fs),
@@ -34,7 +34,9 @@ instance Show Query where
         Just (showCollection c),
         showJoinClauses js,
         showEmbedClauses es,
-        showWhereClause w
+        showWhereClause w,
+        showLimitClause l,
+        showOffsetClause o
       ]
   show (Update c v w) =
     intercalate " " . catMaybes $
@@ -106,6 +108,14 @@ showComparison (Eq a b) = intercalate " " [showArg a, "==", showArg b]
   where
     showArg = either showValue showField
 
+showOffsetClause :: Maybe OffsetClause -> Maybe String
+showOffsetClause (Just (Offset n)) = Just (" OFFSET %d" <> show n)
+showOffsetClause Nothing = Nothing
+
+showLimitClause :: Maybe LimitClause -> Maybe String
+showLimitClause (Just (Limit n)) = Just (" LIMIT %d" <> show n)
+showLimitClause Nothing = Nothing
+
 showValues :: [J.Value] -> Maybe String
 showValues [] = Nothing
 showValues vs = Just (intercalate ", " (map showValue vs))
diff --git a/src/Store/Query/Type.hs b/src/Store/Query/Type.hs
index 912d020..b431f6c 100644
--- a/src/Store/Query/Type.hs
+++ b/src/Store/Query/Type.hs
@@ -11,6 +11,8 @@ module Store.Query.Type
     JoinType (..),
     Query (..),
     WhereClause (..),
+    LimitClause (..),
+    OffsetClause (..),
   )
 where
 
@@ -18,6 +20,7 @@ import Data.Aeson qualified as J
 import Data.Map qualified as M
 import Store.Query.Field
 import Store.Query.Record
+import Text.Regex.PCRE
 
 data Query
   = Delete Collection (Maybe WhereClause)
@@ -28,6 +31,8 @@ data Query
       (JoinClauses FilePath)
       (EmbedClauses FilePath)
       (Maybe WhereClause)
+      (Maybe LimitClause)
+      (Maybe OffsetClause)
   | Update Collection J.Value (Maybe WhereClause)
 
 data FieldSelector
@@ -63,4 +68,14 @@ data WhereClause
 
 data Comparison
   = Eq (Either J.Value Field) (Either J.Value Field)
+  | Regex (Either J.Value Field) Regex
+  deriving (Show)
+
+instance Show Regex where
+  show _ = "<REGEX>"
+
+data LimitClause = Limit Int
+  deriving (Show)
+
+data OffsetClause = Offset Int
   deriving (Show)