PureScript's equivalent to Haskell's Hoogle is Pursuit. Just like Hoogle you can search using either names or type signatures:
http://pursuit.purescript.org/search?q=%2B
http://pursuit.purescript.org/search?q=Int+-%3E+Int+-%3E+Int
If you want programmatic access you can get the output in JSON format:
curl -H 'Accept: application/json' http://pursuit.purescript.org/search?q=Int+-%3E+Int+-%3E+Int