diff --git a/library/Optima.hs b/library/Optima.hs
--- a/library/Optima.hs
+++ b/library/Optima.hs
@@ -8,6 +8,7 @@
   -- * Param
   Param,
   value,
+  switch,
   -- * Value
   Value,
   explicitlyParsed,
@@ -19,7 +20,7 @@
   defaultless,
   -- * ValueFormat
   ValueFormat,
-  enum,
+  formattedByEnum,
   unformatted,
 )
 where
@@ -49,6 +50,11 @@
 newtype Param a = Param (Maybe Char -> Text -> Optparse.Parser a)
 
 {-|
+Parameter product, which gets resolved by prefixing the names
+-}
+newtype ProductParam a = ProductParam (Text -> Optparse.Parser a)
+
+{-|
 Parameter value parser.
 -}
 newtype Value a = Value (Attoparsec.Parser a)
@@ -129,7 +135,16 @@
       paramHelp description format <>
       defaultValue def
 
+{-|
+A parameter with no value, the presence of which is interpreted as 'True'.
+-}
+switch :: Text {-^ Description. Can be empty -} -> Param Bool
+switch description =
+  Param (\ shortName longName ->
+    Optparse.switch
+      (longParamName longName <> foldMap Optparse.short shortName <> paramHelp description UnspecifiedFormat))
 
+
 -- ** Value
 -------------------------
 
@@ -174,8 +189,8 @@
 {-|
 Derive value format specification from the Enum instance.
 -}
-enum :: (Bounded a, Enum a, Show a) => ValueFormat a
-enum = let
+formattedByEnum :: (Bounded a, Enum a, Show a) => ValueFormat a
+formattedByEnum = let
   values = enumFromTo minBound (asTypeOf maxBound (descriptionToA description))
   descriptionToA = undefined :: ValueFormat a -> a
   description = EnumValueFormat (fmap (TextBuilder.string . show) values)
diff --git a/optima.cabal b/optima.cabal
--- a/optima.cabal
+++ b/optima.cabal
@@ -1,5 +1,5 @@
 name: optima
-version: 0.1
+version: 0.1.1
 category: CLI, Parsing, Options
 synopsis: Simple command line interface arguments parser
 homepage: https://github.com/metrix-ai/optima