I'm using the PCRE library to validate the email in haskell.
Below is my code -
import ClassyPrelude
import Domain.Validation
import Text.Regex.PCRE.Heavy
import Control.Monad.Except
type Validation e a = a -> Maybe e
validate :: (a -> b) -> [Validation e a] -> a -> Either [e] b
validate constructor validations val =
case concatMap (\f -> maybeToList $ f val) validations of
[] -> Right $ constructor val
errs -> Left errs
newtype Email = Email { emailRaw :: Text } deriving (Show, Eq, Ord)
rawEmail :: Email -> Text
rawEmail = emailRaw
mkEmail :: Text -> Either [Text] Email
mkEmail =
validate Email
[ regexMatches
[re|^[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,64}$|]
"Not a valid email"
]
Below are my cabal settings -
default-extensions: TemplateHaskell
, ConstraintKinds
, FlexibleContexts
, NoImplicitPrelude
, OverloadedStrings
, TemplateHaskell
build-depends: base ^>=4.21.0.0
, katip >= 0.8.8.2
, string-random == 0.1.4.4
, mtl
, data-has
, classy-prelude
, pcre-heavy
, time
, time-lens
hs-source-dirs: src
default-language: GHC2024
When I do cabal build, I get the below error -
cabal build
Resolving dependencies...
Build profile: -w ghc-9.12.2 -O1
In order, the following will be built (use -v for more details):
- practical-web-dev-ghc-0.1.0.0 (lib) (first run)
- practical-web-dev-ghc-0.1.0.0 (exe:practical-web-dev-ghc) (first run)
Configuring library for practical-web-dev-ghc-0.1.0.0...
Preprocessing library for practical-web-dev-ghc-0.1.0.0...
Building library for practical-web-dev-ghc-0.1.0.0...
[1 of 5] Compiling Domain.Validation ( src/Domain/Validation.hs, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/Domain/Validation.o, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/Domain/Validation.dyn_o )
[2 of 5] Compiling Domain.Auth ( src/Domain/Auth.hs, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/Domain/Auth.o, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/Domain/Auth.dyn_o )
src/Domain/Auth.hs:42:57: error: [GHC-58481]
parse error on input ‘2’
|
42 | [re|^[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,64}$|]
| ^
[4 of 5] Compiling Logger ( src/Logger.hs, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/Logger.o, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/Logger.dyn_o )
[5 of 5] Compiling MyLib ( src/MyLib.hs, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/MyLib.o, dist-newstyle/build/aarch64-osx/ghc-9.12.2/practical-web-dev-ghc-0.1.0.0/build/MyLib.dyn_o )
Error: [Cabal-7125]
Failed to build practical-web-dev-ghc-0.1.0.0 (which is required by exe:practical-web-dev-ghc from practical-web-dev-ghc-0.1.0.0).
Note: The haskell version I'm using is
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.12.2
This is example from Practical Web Development with Haskell and the project is in github here
You need the QuasiQuotes extension. You can turn it on by adding it to the default-extensions field of your cabal file or by adding {-# Language QuasiQuotes #-} to the top of your Haskell file.