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Diffstat (limited to 'users/Profpatsch/my-prelude')
| -rw-r--r-- | users/Profpatsch/my-prelude/README.md | 42 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/default.nix | 48 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/my-prelude.cabal | 107 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/Aeson.hs | 176 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/AtLeast.hs | 51 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/MyPrelude.hs | 587 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/Postgres/Decoder.hs | 94 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/Postgres/MonadPostgres.hs | 583 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/Seconds.hs | 55 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/Test.hs | 115 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/Tool.hs | 75 | ||||
| -rw-r--r-- | users/Profpatsch/my-prelude/src/ValidationParseT.hs | 16 |
12 files changed, 1949 insertions, 0 deletions
diff --git a/users/Profpatsch/my-prelude/README.md b/users/Profpatsch/my-prelude/README.md new file mode 100644 index 000000000000..2cc068579a52 --- /dev/null +++ b/users/Profpatsch/my-prelude/README.md @@ -0,0 +1,42 @@ +# My Haskell Prelude + +Contains various modules I’ve found useful when writing Haskell. + +## Contents + +A short overview: + +### `MyPrelude.hs` + +A collection of re-exports and extra functions. This does *not* replace the `Prelude` module from `base`, but rather should be imported *in addition* to `Prelude`. + +Stuff like bad functions from prelude (partial stuff, or plain horrible stuff) are handled by a custom `.hlint` file, which you can find in [../.hlint.yaml](). + +The common style of haskell they try to enable is what I call “left-to-right Haskell”, +where one mostly prefers forward-chaining operators like `&`/`<&>`/`>>=` to backwards operators like `$`/`<$>`/`<=<`. In addition, all transformation function should follow the scheme of `aToB` instead of `B.fromA`, e.g. `Text.unpack`/`Text.pack` -> `textToString`/`stringToText`. Includes a bunch of text conversion functions one needs all the time, in the same style. + +These have been battle-tested in a production codebase of ~30k lines of Haskell. + +### `Label.hs` + +A very useful collection of anonymous labbeled tuples and enums of size 2 and 3. Assumes GHC >9.2 for `RecordDotSyntax` support. + +### `Pretty.hs` + +Colorful multiline pretty-printing of Haskell values. + +### `Test.hs` + +A wrapper around `hspec` which produces colorful test diffs. + +### `Aeson.hs` + +Helpers around Json parsing. + +### `Data.Error.Tree` + +Collect errors (from [`Data.Error`](https://hackage.haskell.org/package/error-1.0.0.0/docs/Data-Error.html)) into a tree, then display them in a nested fashion. Super useful for e.g. collecting and displaying nested parsing errors. + +### `RunCommand.hs` + +A module wrapping the process API with some helpful defaults for executing commands and printing what is executed to stderr. diff --git a/users/Profpatsch/my-prelude/default.nix b/users/Profpatsch/my-prelude/default.nix new file mode 100644 index 000000000000..5ed68026db50 --- /dev/null +++ b/users/Profpatsch/my-prelude/default.nix @@ -0,0 +1,48 @@ +{ depot, pkgs, lib, ... }: + +pkgs.haskellPackages.mkDerivation { + pname = "my-prelude"; + version = "0.0.1-unreleased"; + + src = depot.users.Profpatsch.exactSource ./. [ + ./my-prelude.cabal + ./src/Aeson.hs + ./src/AtLeast.hs + ./src/MyPrelude.hs + ./src/Test.hs + ./src/Seconds.hs + ./src/Tool.hs + ./src/ValidationParseT.hs + ./src/Postgres/Decoder.hs + ./src/Postgres/MonadPostgres.hs + ]; + + isLibrary = true; + + libraryHaskellDepends = [ + pkgs.haskellPackages.pa-prelude + pkgs.haskellPackages.pa-label + pkgs.haskellPackages.pa-error-tree + pkgs.haskellPackages.pa-json + pkgs.haskellPackages.pa-pretty + pkgs.haskellPackages.pa-field-parser + pkgs.haskellPackages.aeson-better-errors + pkgs.haskellPackages.resource-pool + pkgs.haskellPackages.error + pkgs.haskellPackages.hs-opentelemetry-api + pkgs.haskellPackages.hspec + pkgs.haskellPackages.hspec-expectations-pretty-diff + pkgs.haskellPackages.monad-logger + pkgs.haskellPackages.postgresql-simple + pkgs.haskellPackages.profunctors + pkgs.haskellPackages.PyF + pkgs.haskellPackages.semigroupoids + pkgs.haskellPackages.these + pkgs.haskellPackages.unliftio + pkgs.haskellPackages.validation-selective + pkgs.haskellPackages.vector + ]; + + license = lib.licenses.mit; + +} diff --git a/users/Profpatsch/my-prelude/my-prelude.cabal b/users/Profpatsch/my-prelude/my-prelude.cabal new file mode 100644 index 000000000000..c811c00e0adf --- /dev/null +++ b/users/Profpatsch/my-prelude/my-prelude.cabal @@ -0,0 +1,107 @@ +cabal-version: 3.0 +name: my-prelude +version: 0.0.1.0 +author: Profpatsch +maintainer: mail@profpatsch.de + +common common-options + ghc-options: + -Wall + -Wno-type-defaults + -Wunused-packages + -Wredundant-constraints + -fwarn-missing-deriving-strategies + + -- See https://downloads.haskell.org/ghc/latest/docs/users_guide/exts.html + -- for a description of all these extensions + default-extensions: + -- Infer Applicative instead of Monad where possible + ApplicativeDo + + -- Allow literal strings to be Text + OverloadedStrings + + -- Syntactic sugar improvements + LambdaCase + MultiWayIf + + -- Makes the (deprecated) usage of * instead of Data.Kind.Type an error + NoStarIsType + + -- Convenient and crucial to deal with ambiguous field names, commonly + -- known as RecordDotSyntax + OverloadedRecordDot + + -- does not export record fields as functions, use OverloadedRecordDot to access instead + NoFieldSelectors + + -- Record punning + RecordWildCards + + -- Improved Deriving + DerivingStrategies + DerivingVia + + -- Type-level strings + DataKinds + + -- to enable the `type` keyword in import lists (ormolu uses this automatically) + ExplicitNamespaces + + default-language: GHC2021 + + +library + import: common-options + hs-source-dirs: src + exposed-modules: + MyPrelude + Aeson + AtLeast + Test + Postgres.Decoder + Postgres.MonadPostgres + ValidationParseT + Seconds + Tool + + -- Modules included in this executable, other than Main. + -- other-modules: + + -- LANGUAGE extensions used by modules in this package. + -- other-extensions: + build-depends: + base >=4.15 && <5 + , pa-prelude + , pa-label + , pa-error-tree + , pa-json + , pa-pretty + , pa-field-parser + , aeson + , aeson-better-errors + , bytestring + , containers + , resource-pool + , resourcet + , scientific + , time + , error + , exceptions + , filepath + , hspec + , hspec-expectations-pretty-diff + , hs-opentelemetry-api + , monad-logger + , mtl + , postgresql-simple + , profunctors + , PyF + , semigroupoids + , selective + , text + , these + , unix + , unliftio + , validation-selective + , vector diff --git a/users/Profpatsch/my-prelude/src/Aeson.hs b/users/Profpatsch/my-prelude/src/Aeson.hs new file mode 100644 index 000000000000..73d611608224 --- /dev/null +++ b/users/Profpatsch/my-prelude/src/Aeson.hs @@ -0,0 +1,176 @@ +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE GHC2021 #-} +{-# LANGUAGE KindSignatures #-} +{-# LANGUAGE LambdaCase #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE UndecidableInstances #-} + +module Aeson where + +import Data.Aeson (Value (..)) +import Data.Aeson.BetterErrors qualified as Json +import Data.Aeson.KeyMap qualified as KeyMap +import Data.Error.Tree +import Data.Maybe (catMaybes) +import Data.Vector qualified as Vector +import Label +import PossehlAnalyticsPrelude +import Test.Hspec (describe, it, shouldBe) +import Test.Hspec qualified as Hspec + +-- | Convert a 'Json.ParseError' to a corresponding 'ErrorTree' +parseErrorTree :: Error -> Json.ParseError Error -> ErrorTree +parseErrorTree contextMsg errs = + errs + & Json.displayError prettyError + <&> newError + & nonEmpty + & \case + Nothing -> singleError contextMsg + Just errs' -> errorTree contextMsg errs' + +-- | Parse a key from the object, à la 'Json.key', return a labelled value. +-- +-- We don’t provide a version that infers the json object key, +-- since that conflates internal naming with the external API, which is dangerous. +-- +-- @@ +-- do +-- txt <- keyLabel @"myLabel" "jsonKeyName" Json.asText +-- pure (txt :: Label "myLabel" Text) +-- @@ +keyLabel :: + forall label err m a. + Monad m => + Text -> + Json.ParseT err m a -> + Json.ParseT err m (Label label a) +keyLabel = do + keyLabel' (Proxy @label) + +-- | Parse a key from the object, à la 'Json.key', return a labelled value. +-- Version of 'keyLabel' that requires a proxy. +-- +-- @@ +-- do +-- txt <- keyLabel' (Proxy @"myLabel") "jsonKeyName" Json.asText +-- pure (txt :: Label "myLabel" Text) +-- @@ +keyLabel' :: + forall label err m a. + Monad m => + Proxy label -> + Text -> + Json.ParseT err m a -> + Json.ParseT err m (Label label a) +keyLabel' Proxy key parser = label @label <$> Json.key key parser + +-- | Parse an optional key from the object, à la 'Json.keyMay', return a labelled value. +-- +-- We don’t provide a version that infers the json object key, +-- since that conflates internal naming with the external API, which is dangerous. +-- +-- @@ +-- do +-- txt <- keyLabelMay @"myLabel" "jsonKeyName" Json.asText +-- pure (txt :: Label "myLabel" (Maybe Text)) +-- @@ +keyLabelMay :: + forall label err m a. + Monad m => + Text -> + Json.ParseT err m a -> + Json.ParseT err m (Label label (Maybe a)) +keyLabelMay = do + keyLabelMay' (Proxy @label) + +-- | Parse an optional key from the object, à la 'Json.keyMay', return a labelled value. +-- Version of 'keyLabelMay' that requires a proxy. +-- +-- @@ +-- do +-- txt <- keyLabelMay' (Proxy @"myLabel") "jsonKeyName" Json.asText +-- pure (txt :: Label "myLabel" (Maybe Text)) +-- @@ +keyLabelMay' :: + forall label err m a. + Monad m => + Proxy label -> + Text -> + Json.ParseT err m a -> + Json.ParseT err m (Label label (Maybe a)) +keyLabelMay' Proxy key parser = label @label <$> Json.keyMay key parser + +-- | Like 'Json.key', but allows a list of keys that are tried in order. +-- +-- This is intended for renaming keys in an object. +-- The first key is the most up-to-date version of a key, the others are for backward-compatibility. +-- +-- If a key (new or old) exists, the inner parser will always be executed for that key. +keyRenamed :: Monad m => NonEmpty Text -> Json.ParseT err m a -> Json.ParseT err m a +keyRenamed (newKey :| oldKeys) inner = + keyRenamedTryOldKeys oldKeys inner >>= \case + Nothing -> Json.key newKey inner + Just parse -> parse + +-- | Like 'Json.keyMay', but allows a list of keys that are tried in order. +-- +-- This is intended for renaming keys in an object. +-- The first key is the most up-to-date version of a key, the others are for backward-compatibility. +-- +-- If a key (new or old) exists, the inner parser will always be executed for that key. +keyRenamedMay :: Monad m => NonEmpty Text -> Json.ParseT err m a -> Json.ParseT err m (Maybe a) +keyRenamedMay (newKey :| oldKeys) inner = + keyRenamedTryOldKeys oldKeys inner >>= \case + Nothing -> Json.keyMay newKey inner + Just parse -> Just <$> parse + +-- | Helper function for 'keyRenamed' and 'keyRenamedMay' that returns the parser for the first old key that exists, if any. +keyRenamedTryOldKeys :: Monad m => [Text] -> Json.ParseT err m a -> Json.ParseT err m (Maybe (Json.ParseT err m a)) +keyRenamedTryOldKeys oldKeys inner = do + oldKeys & traverse tryOld <&> catMaybes <&> nonEmpty <&> \case + Nothing -> Nothing + Just (old :| _moreOld) -> Just old + where + tryOld key = + Json.keyMay key (pure ()) <&> \case + Just () -> Just $ Json.key key inner + Nothing -> Nothing + +test_keyRenamed :: Hspec.Spec +test_keyRenamed = do + describe "keyRenamed" $ do + let parser = keyRenamed ("new" :| ["old"]) Json.asText + let p = Json.parseValue @() parser + it "accepts the new key and the old key" $ do + p (Object (KeyMap.singleton "new" (String "text"))) + `shouldBe` (Right "text") + p (Object (KeyMap.singleton "old" (String "text"))) + `shouldBe` (Right "text") + it "fails with the old key in the error if the inner parser is wrong" $ do + p (Object (KeyMap.singleton "old" Null)) + `shouldBe` (Left (Json.BadSchema [Json.ObjectKey "old"] (Json.WrongType Json.TyString Null))) + it "fails with the new key in the error if the inner parser is wrong" $ do + p (Object (KeyMap.singleton "new" Null)) + `shouldBe` (Left (Json.BadSchema [Json.ObjectKey "new"] (Json.WrongType Json.TyString Null))) + it "fails if the key is missing" $ do + p (Object KeyMap.empty) + `shouldBe` (Left (Json.BadSchema [] (Json.KeyMissing "new"))) + describe "keyRenamedMay" $ do + let parser = keyRenamedMay ("new" :| ["old"]) Json.asText + let p = Json.parseValue @() parser + it "accepts the new key and the old key" $ do + p (Object (KeyMap.singleton "new" (String "text"))) + `shouldBe` (Right (Just "text")) + p (Object (KeyMap.singleton "old" (String "text"))) + `shouldBe` (Right (Just "text")) + it "allows the old and new key to be missing" $ do + p (Object KeyMap.empty) + `shouldBe` (Right Nothing) + +-- | Create a json array from a list of json values. +jsonArray :: [Value] -> Value +jsonArray xs = xs & Vector.fromList & Array diff --git a/users/Profpatsch/my-prelude/src/AtLeast.hs b/users/Profpatsch/my-prelude/src/AtLeast.hs new file mode 100644 index 000000000000..3857c3a7cfe7 --- /dev/null +++ b/users/Profpatsch/my-prelude/src/AtLeast.hs @@ -0,0 +1,51 @@ +{-# LANGUAGE QuasiQuotes #-} + +module AtLeast where + +import Data.Aeson (FromJSON (parseJSON)) +import Data.Aeson.BetterErrors qualified as Json +import FieldParser (FieldParser) +import FieldParser qualified as Field +import GHC.Records (HasField (..)) +import GHC.TypeLits (KnownNat, natVal) +import PossehlAnalyticsPrelude + ( Natural, + Proxy (Proxy), + fmt, + prettyError, + (&), + ) + +-- | A natural number that must be at least as big as the type literal. +newtype AtLeast (min :: Natural) num = AtLeast num + -- Just use the instances of the wrapped number type + deriving newtype (Eq, Show) + +-- | This is the “destructor” for `AtLeast`, because of the phantom type (@min@) it cannot be inferred automatically. +instance HasField "unAtLeast" (AtLeast min num) num where + getField (AtLeast num) = num + +parseAtLeast :: + forall min num. + (KnownNat min, Integral num, Show num) => + FieldParser num (AtLeast min num) +parseAtLeast = + let minInt = natVal (Proxy @min) + in Field.FieldParser $ \from -> + if from >= (minInt & fromIntegral) + then Right (AtLeast from) + else Left [fmt|Must be at least {minInt & show} but was {from & show}|] + +instance + (KnownNat min, FromJSON num, Integral num, Bounded num, Show num) => + FromJSON (AtLeast min num) + where + parseJSON = + Json.toAesonParser + prettyError + ( do + num <- Json.fromAesonParser @_ @num + case Field.runFieldParser (parseAtLeast @min @num) num of + Left err -> Json.throwCustomError err + Right a -> pure a + ) diff --git a/users/Profpatsch/my-prelude/src/MyPrelude.hs b/users/Profpatsch/my-prelude/src/MyPrelude.hs new file mode 100644 index 000000000000..1be248d091a9 --- /dev/null +++ b/users/Profpatsch/my-prelude/src/MyPrelude.hs @@ -0,0 +1,587 @@ +{-# LANGUAGE ImplicitParams #-} +{-# LANGUAGE LambdaCase #-} +{-# LANGUAGE MagicHash #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE RankNTypes #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# OPTIONS_GHC -fexpose-all-unfoldings #-} + +module MyPrelude + ( -- * Text conversions + Text, + ByteString, + Word8, + fmt, + textToString, + stringToText, + showToText, + textToBytesUtf8, + textToBytesUtf8Lazy, + bytesToTextUtf8, + bytesToTextUtf8Lazy, + bytesToTextUtf8Lenient, + bytesToTextUtf8LenientLazy, + bytesToTextUtf8Unsafe, + bytesToTextUtf8UnsafeLazy, + toStrict, + toLazy, + toStrictBytes, + toLazyBytes, + charToWordUnsafe, + + -- * IO + putStrLn, + putStderrLn, + exitWithMessage, + + -- * WIP code + todo, + + -- * Records + HasField, + + -- * Control flow + (&), + (<&>), + (<|>), + foldMap1, + foldMap', + join, + when, + unless, + guard, + ExceptT (..), + runExceptT, + MonadThrow, + throwM, + MonadIO, + liftIO, + MonadReader, + asks, + Bifunctor, + first, + second, + bimap, + both, + foldMap, + fold, + foldl', + fromMaybe, + mapMaybe, + findMaybe, + Traversable, + for, + for_, + traverse, + traverse_, + traverseFold, + traverseFold1, + traverseFoldDefault, + MonadTrans, + lift, + + -- * Data types + Coercible, + coerce, + Proxy (Proxy), + Map, + annotate, + Validation (Success, Failure), + failure, + successes, + failures, + eitherToValidation, + eitherToListValidation, + validationToEither, + These (This, That, These), + eitherToThese, + eitherToListThese, + validationToThese, + thenThese, + thenValidate, + NonEmpty ((:|)), + singleton, + nonEmpty, + nonEmptyDef, + toList, + toNonEmptyDefault, + maximum1, + minimum1, + Generic, + Semigroup, + sconcat, + Monoid, + mconcat, + ifTrue, + ifExists, + Void, + absurd, + Identity (Identity, runIdentity), + Natural, + intToNatural, + Contravariant, + contramap, + (>$<), + (>&<), + Profunctor, + dimap, + lmap, + rmap, + Semigroupoid, + Category, + (>>>), + (&>>), + + -- * Enum definition + inverseFunction, + inverseMap, + + -- * Error handling + HasCallStack, + module Data.Error, + ) +where + +import Control.Applicative ((<|>)) +import Control.Category (Category, (>>>)) +import Control.Monad (guard, join, unless, when) +import Control.Monad.Catch (MonadThrow (throwM)) +import Control.Monad.Except + ( ExceptT (..), + runExceptT, + ) +import Control.Monad.IO.Class (MonadIO, liftIO) +import Control.Monad.Identity (Identity (Identity)) +import Control.Monad.Reader (MonadReader, asks) +import Control.Monad.Trans (MonadTrans (lift)) +import Data.Bifunctor (Bifunctor, bimap, first, second) +import Data.ByteString + ( ByteString, + ) +import Data.ByteString.Lazy qualified +import Data.Char qualified +import Data.Coerce (Coercible, coerce) +import Data.Data (Proxy (Proxy)) +import Data.Error +import Data.Foldable (Foldable (foldMap', toList), fold, foldl', for_, traverse_) +import Data.Foldable qualified as Foldable +import Data.Function ((&)) +import Data.Functor ((<&>)) +import Data.Functor.Contravariant (Contravariant (contramap), (>$<)) +import Data.Functor.Identity (Identity (runIdentity)) +import Data.List.NonEmpty (NonEmpty ((:|)), nonEmpty) +import Data.Map.Strict + ( Map, + ) +import Data.Map.Strict qualified as Map +import Data.Maybe (fromMaybe, mapMaybe) +import Data.Maybe qualified as Maybe +import Data.Profunctor (Profunctor, dimap, lmap, rmap) +import Data.Semigroup (Max (Max, getMax), Min (Min, getMin), sconcat) +import Data.Semigroup.Foldable (Foldable1 (fold1), foldMap1) +import Data.Semigroup.Traversable (Traversable1) +import Data.Semigroupoid (Semigroupoid (o)) +import Data.Text + ( Text, + ) +import Data.Text qualified +import Data.Text.Encoding qualified +import Data.Text.Encoding.Error qualified +import Data.Text.Lazy qualified +import Data.Text.Lazy.Encoding qualified +import Data.These (These (That, These, This)) +import Data.Traversable (for) +import Data.Void (Void, absurd) +import Data.Word (Word8) +import GHC.Exception (errorCallWithCallStackException) +import GHC.Exts (RuntimeRep, TYPE, raise#) +import GHC.Generics (Generic) +import GHC.Natural (Natural) +import GHC.Records (HasField) +import GHC.Stack (HasCallStack) +import PyF (fmt) +import System.Exit qualified +import System.IO qualified +import Validation + ( Validation (Failure, Success), + eitherToValidation, + failure, + failures, + successes, + validationToEither, + ) + +-- | Forward-applying 'contramap', like '&'/'$' and '<&>'/'<$>' but for '>$<'. +(>&<) :: Contravariant f => f b -> (a -> b) -> f a +(>&<) = flip contramap + +infixl 5 >&< + +-- | Forward semigroupoid application. The same as '(>>>)', but 'Semigroupoid' is not a superclass of 'Category' (yet). +-- +-- Specialized examples: +-- +-- @@ +-- for functions : (a -> b) -> (b -> c) -> (a -> c) +-- for Folds: Fold a b -> Fold b c -> Fold a c +-- @@ +(&>>) :: Semigroupoid s => s a b -> s b c -> s a c +(&>>) = flip Data.Semigroupoid.o + +-- like >>> +infixr 1 &>> + +-- | encode a Text to a UTF-8 encoded Bytestring +textToBytesUtf8 :: Text -> ByteString +textToBytesUtf8 = Data.Text.Encoding.encodeUtf8 + +-- | encode a lazy Text to a UTF-8 encoded lazy Bytestring +textToBytesUtf8Lazy :: Data.Text.Lazy.Text -> Data.ByteString.Lazy.ByteString +textToBytesUtf8Lazy = Data.Text.Lazy.Encoding.encodeUtf8 + +bytesToTextUtf8 :: ByteString -> Either Error Text +bytesToTextUtf8 = first exceptionToError . Data.Text.Encoding.decodeUtf8' + +bytesToTextUtf8Lazy :: Data.ByteString.Lazy.ByteString -> Either Error Data.Text.Lazy.Text +bytesToTextUtf8Lazy = first exceptionToError . Data.Text.Lazy.Encoding.decodeUtf8' + +-- | decode a Text from a ByteString that is assumed to be UTF-8 (crash if that is not the case) +bytesToTextUtf8Unsafe :: ByteString -> Text +bytesToTextUtf8Unsafe = Data.Text.Encoding.decodeUtf8 + +-- | decode a Text from a ByteString that is assumed to be UTF-8 (crash if that is not the case) +bytesToTextUtf8UnsafeLazy :: Data.ByteString.Lazy.ByteString -> Data.Text.Lazy.Text +bytesToTextUtf8UnsafeLazy = Data.Text.Lazy.Encoding.decodeUtf8 + +-- | decode a Text from a ByteString that is assumed to be UTF-8, +-- replace non-UTF-8 characters with the replacment char U+FFFD. +bytesToTextUtf8Lenient :: Data.ByteString.ByteString -> Data.Text.Text +bytesToTextUtf8Lenient = + Data.Text.Encoding.decodeUtf8With Data.Text.Encoding.Error.lenientDecode + +-- | decode a lazy Text from a lazy ByteString that is assumed to be UTF-8, +-- replace non-UTF-8 characters with the replacment char U+FFFD. +bytesToTextUtf8LenientLazy :: Data.ByteString.Lazy.ByteString -> Data.Text.Lazy.Text +bytesToTextUtf8LenientLazy = + Data.Text.Lazy.Encoding.decodeUtf8With Data.Text.Encoding.Error.lenientDecode + +-- | Make a lazy text strict +toStrict :: Data.Text.Lazy.Text -> Text +toStrict = Data.Text.Lazy.toStrict + +-- | Make a strict text lazy +toLazy :: Text -> Data.Text.Lazy.Text +toLazy = Data.Text.Lazy.fromStrict + +toStrictBytes :: Data.ByteString.Lazy.ByteString -> ByteString +toStrictBytes = Data.ByteString.Lazy.toStrict + +toLazyBytes :: ByteString -> Data.ByteString.Lazy.ByteString +toLazyBytes = Data.ByteString.Lazy.fromStrict + +textToString :: Text -> String +textToString = Data.Text.unpack + +stringToText :: String -> Text +stringToText = Data.Text.pack + +showToText :: (Show a) => a -> Text +showToText = stringToText . show + +-- | Unsafe conversion between 'Char' and 'Word8'. This is a no-op and +-- silently truncates to 8 bits Chars > '\255'. It is provided as +-- convenience for ByteString construction. +-- +-- Use if you want to get the 'Word8' representation of a character literal. +-- Don’t use on arbitrary characters! +-- +-- >>> charToWordUnsafe ',' +-- 44 +charToWordUnsafe :: Char -> Word8 +charToWordUnsafe = fromIntegral . Data.Char.ord +{-# INLINE charToWordUnsafe #-} + +-- | Single element in a (non-empty) list. +singleton :: a -> NonEmpty a +singleton a = a :| [] + +-- | If the given list is empty, use the given default element and return a non-empty list. +nonEmptyDef :: a -> [a] -> NonEmpty a +nonEmptyDef def xs = + xs & nonEmpty & \case + Nothing -> def :| [] + Just ne -> ne + +-- | Construct a non-empty list, given a default value if the ist list was empty. +toNonEmptyDefault :: a -> [a] -> NonEmpty a +toNonEmptyDefault def xs = case xs of + [] -> def :| [] + (x : xs') -> x :| xs' + +-- | @O(n)@. Get the maximum element from a non-empty structure. +maximum1 :: (Foldable1 f, Ord a) => f a -> a +maximum1 xs = xs & foldMap1 Max & getMax + +-- | @O(n)@. Get the minimum element from a non-empty structure. +minimum1 :: (Foldable1 f, Ord a) => f a -> a +minimum1 xs = xs & foldMap1 Min & getMin + +-- | Annotate a 'Maybe' with an error message and turn it into an 'Either'. +annotate :: err -> Maybe a -> Either err a +annotate err = \case + Nothing -> Left err + Just a -> Right a + +-- | Map the same function over both sides of a Bifunctor (e.g. a tuple). +both :: Bifunctor bi => (a -> b) -> bi a a -> bi b b +both f = bimap f f + +-- | Find the first element for which pred returns `Just a`, and return the `a`. +-- +-- Example: +-- @ +-- >>> :set -XTypeApplications +-- >>> import qualified Text.Read +-- +-- >>> findMaybe (Text.Read.readMaybe @Int) ["foo"] +-- Nothing +-- >>> findMaybe (Text.Read.readMaybe @Int) ["foo", "34.40", "34", "abc"] +-- Just 34 +findMaybe :: Foldable t => (a -> Maybe b) -> t a -> Maybe b +findMaybe mPred list = + let pred' x = Maybe.isJust $ mPred x + in case Foldable.find pred' list of + Just a -> mPred a + Nothing -> Nothing + +-- | Like 'eitherToValidation', but puts the Error side into a NonEmpty list +-- to make it combine with other validations. +eitherToListValidation :: Either a c -> Validation (NonEmpty a) c +eitherToListValidation = first singleton . eitherToValidation + +-- | Convert an 'Either' to a 'These'. +eitherToThese :: Either err a -> These err a +eitherToThese (Left err) = This err +eitherToThese (Right a) = That a + +-- | Like 'eitherToThese', but puts the Error side into a NonEmpty list +-- to make it combine with other theses. +eitherToListThese :: Either err a -> These (NonEmpty err) a +eitherToListThese (Left e) = This (singleton e) +eitherToListThese (Right a) = That a + +-- | Convert a 'Validation' to a 'These'. +validationToThese :: Validation err a -> These err a +validationToThese (Failure err) = This err +validationToThese (Success a) = That a + +-- | Nested '>>=' of a These inside some other @m@. +-- +-- Use if you want to collect errors and successes, and want to chain multiple function returning 'These'. +thenThese :: + (Monad m, Semigroup err) => + (a -> m (These err b)) -> + m (These err a) -> + m (These err b) +thenThese f x = do + th <- x + join <$> traverse f th + +-- | Nested validating bind-like combinator inside some other @m@. +-- +-- Use if you want to collect errors, and want to chain multiple functions returning 'Validation'. +thenValidate :: + (Monad m) => + (a -> m (Validation err b)) -> + m (Validation err a) -> + m (Validation err b) +thenValidate f x = + eitherToValidation <$> do + x' <- validationToEither <$> x + case x' of + Left err -> pure $ Left err + Right a -> validationToEither <$> f a + +-- | Put the text to @stderr@. +putStderrLn :: Text -> IO () +putStderrLn msg = + System.IO.hPutStrLn System.IO.stderr $ textToString msg + +exitWithMessage :: Text -> IO a +exitWithMessage msg = do + putStderrLn msg + System.Exit.exitWith $ System.Exit.ExitFailure (-1) + +-- | Run some function producing applicative over a traversable data structure, +-- then collect the results in a Monoid. +-- +-- Very helpful with side-effecting functions returning @(Validation err a)@: +-- +-- @ +-- let +-- f :: Text -> IO (Validation (NonEmpty Error) Text) +-- f t = pure $ if t == "foo" then Success t else Failure (singleton ("not foo: " <> t)) +-- +-- in traverseFold f [ "foo", "bar", "baz" ] +-- == Failure ("not foo bar" :| ["not foo baz"]) +-- @ +-- +-- … since @(Semigroup err => Validation err a)@ is a @Semigroup@/@Monoid@ itself. +traverseFold :: (Applicative ap, Traversable t, Monoid m) => (a -> ap m) -> t a -> ap m +traverseFold f xs = + -- note: could be weakened to (Foldable t) via `getAp . foldMap (Ap . f)` + fold <$> traverse f xs +{-# INLINE traverseFold #-} + +-- | Like 'traverseFold', but fold over a semigroup instead of a Monoid, by providing a starting element. +traverseFoldDefault :: (Applicative ap, Traversable t, Semigroup m) => m -> (a -> ap m) -> t a -> ap m +traverseFoldDefault def f xs = foldDef def <$> traverse f xs + where + foldDef = foldr (<>) +{-# INLINE traverseFoldDefault #-} + +-- | Same as 'traverseFold', but with a 'Semigroup' and 'Traversable1' restriction. +traverseFold1 :: (Applicative ap, Traversable1 t, Semigroup s) => (a -> ap s) -> t a -> ap s +-- note: cannot be weakened to (Foldable1 t) because there is no `Ap` for Semigroup (No `Apply` typeclass) +traverseFold1 f xs = fold1 <$> traverse f xs +{-# INLINE traverseFold1 #-} + +-- | Use this in places where the code is still to be implemented. +-- +-- It always type-checks and will show a warning at compile time if it was forgotten in the code. +-- +-- Use instead of 'error' and 'undefined' for code that hasn’t been written. +-- +-- Uses the same trick as https://hackage.haskell.org/package/protolude-0.3.0/docs/src/Protolude.Error.html#error +{-# WARNING todo "'todo' (undefined code) remains in code" #-} +todo :: forall (r :: RuntimeRep). forall (a :: TYPE r). HasCallStack => a +todo = raise# (errorCallWithCallStackException "This code was not yet implemented: TODO" ?callStack) + +-- | Convert an integer to a 'Natural' if possible +-- +-- Named the same as the function from "GHC.Natural", but does not crash. +intToNatural :: Integral a => a -> Maybe Natural +intToNatural i = + if i < 0 + then Nothing + else Just $ fromIntegral i + +-- | @inverseFunction f@ creates a function that is the inverse of a given function +-- @f@. It does so by constructing 'M.Map' internally for each value @f a@. The +-- implementation makes sure that the 'M.Map' is constructed only once and then +-- shared for every call. +-- +-- __Memory usage note:__ don't inverse functions that have types like 'Int' +-- as their result. In this case the created 'M.Map' will have huge size. +-- +-- The complexity of reversed mapping is \(\mathcal{O}(\log n)\). +-- +-- __Performance note:__ make sure to specialize monomorphic type of your functions +-- that use 'inverseFunction' to avoid 'M.Map' reconstruction. +-- +-- One of the common 'inverseFunction' use-case is inverting the 'show' or a 'show'-like +-- function. +-- +-- >>> data Color = Red | Green | Blue deriving (Show, Enum, Bounded) +-- >>> parse = inverseFunction show :: String -> Maybe Color +-- >>> parse "Red" +-- Just Red +-- >>> parse "Black" +-- Nothing +-- +-- __Correctness note:__ 'inverseFunction' expects /injective function/ as its argument, +-- i.e. the function must map distinct arguments to distinct values. +-- +-- Typical usage of this function looks like this: +-- +-- @ +-- __data__ GhcVer +-- = Ghc802 +-- | Ghc822 +-- | Ghc844 +-- | Ghc865 +-- | Ghc881 +-- __deriving__ ('Eq', 'Ord', 'Show', 'Enum', 'Bounded') +-- +-- showGhcVer :: GhcVer -> 'Text' +-- showGhcVer = \\__case__ +-- Ghc802 -> "8.0.2" +-- Ghc822 -> "8.2.2" +-- Ghc844 -> "8.4.4" +-- Ghc865 -> "8.6.5" +-- Ghc881 -> "8.8.1" +-- +-- parseGhcVer :: 'Text' -> 'Maybe' GhcVer +-- parseGhcVer = 'inverseFunction' showGhcVer +-- +-- Taken from relude’s @Relude.Extra.Enum@. +inverseFunction :: + forall a k. + (Bounded a, Enum a, Ord k) => + (a -> k) -> + (k -> Maybe a) +inverseFunction f k = Map.lookup k $ inverseMap f + +-- | Like `inverseFunction`, but instead of returning the function +-- it returns a mapping from all possible outputs to their possible inputs. +-- +-- This has the same restrictions of 'inverseFunction'. +inverseMap :: + forall a k. + (Bounded a, Enum a, Ord k) => + (a -> k) -> + Map k a +inverseMap f = + universe + <&> (\a -> (f a, a)) + & Map.fromList + where + universe :: [a] + universe = [minBound .. maxBound] + +-- | If the predicate is true, return the @m@, else 'mempty'. +-- +-- This can be used (together with `ifExists`) to e.g. create lists with optional elements: +-- +-- >>> import Data.Monoid (Sum(..)) +-- +-- >>> :{ mconcat [ +-- ifTrue (1 == 1) [1], +-- [2, 3, 4], +-- ifTrue False [5], +-- ] +-- :} +-- [1,2,3,4] +-- +-- Or any other Monoid: +-- +-- >>> mconcat [ Sum 1, ifTrue (1 == 1) (Sum 2), Sum 3 ] + +-- Sum {getSum = 6} + +ifTrue :: Monoid m => Bool -> m -> m +ifTrue pred' m = if pred' then m else mempty + +-- | If the given @Maybe@ is @Just@, return the @m@, else return mempty. + +-- This can be used (together with `ifTrue`) to e.g. create lists with optional elements: +-- +-- >>> import Data.Monoid (Sum(..)) +-- +-- >>> :{ mconcat [ +-- ifExists (Just [1]), +-- [2, 3, 4], +-- ifExists Nothing, +-- ] +-- :} +-- [1,2,3,4] +-- +-- Or any other Monoid: +-- +-- >>> mconcat [ Sum 1, ifExists (Just (Sum 2)), Sum 3 ] + +-- Sum {getSum = 6} + +ifExists :: Monoid m => Maybe m -> m +ifExists = fold diff --git a/users/Profpatsch/my-prelude/src/Postgres/Decoder.hs b/users/Profpatsch/my-prelude/src/Postgres/Decoder.hs new file mode 100644 index 000000000000..008b89b4ba3d --- /dev/null +++ b/users/Profpatsch/my-prelude/src/Postgres/Decoder.hs @@ -0,0 +1,94 @@ +module Postgres.Decoder where + +import Control.Applicative (Alternative) +import Data.Aeson qualified as Json +import Data.Aeson.BetterErrors qualified as Json +import Data.Error.Tree +import Data.Typeable (Typeable) +import Database.PostgreSQL.Simple (Binary (fromBinary)) +import Database.PostgreSQL.Simple.FromField qualified as PG +import Database.PostgreSQL.Simple.FromRow qualified as PG +import Json qualified +import Label +import PossehlAnalyticsPrelude + +-- | A Decoder of postgres values. Allows embedding more complex parsers (like a 'Json.ParseT'). +newtype Decoder a = Decoder (PG.RowParser a) + deriving newtype (Functor, Applicative, Alternative, Monad) + +-- | Parse a `bytea` field, equivalent to @Binary ByteString@ but avoids the pitfall of having to use 'Binary'. +bytea :: Decoder ByteString +bytea = fromField @(Binary ByteString) <&> (.fromBinary) + +-- | Parse a nullable `bytea` field, equivalent to @Binary ByteString@ but avoids the pitfall of having to use 'Binary'. +byteaMay :: Decoder (Maybe ByteString) +byteaMay = fromField @(Maybe (Binary ByteString)) <&> fmap (.fromBinary) + +-- | Turn any type that implements 'PG.fromField' into a 'Decoder'. Use type applications to prevent accidental conversions: +-- +-- @ +-- fromField @Text :: Decoder Text +-- @ +fromField :: PG.FromField a => Decoder a +fromField = Decoder $ PG.fieldWith PG.fromField + +-- | Turn any type that implements 'PG.fromField' into a 'Decoder' and wrap the result into the given 'Label'. Use type applications to prevent accidental conversions: +-- +-- @ +-- fromField @"myField" @Text :: Decoder (Label "myField" Text) +-- @ +fromFieldLabel :: forall lbl a. PG.FromField a => Decoder (Label lbl a) +fromFieldLabel = label @lbl <$> fromField + +-- | Parse fields out of a json value returned from the database. +-- +-- ATTN: The whole json record has to be transferred before it is parsed, +-- so if you only need a tiny bit of it, use `->` and `->>` in your SQL statement +-- and return only the fields you need from the query. +-- +-- In that case pay attention to NULL though: +-- +-- @ +-- SELECT '{"foo": {}}'::jsonb->>'foo' IS NULL +-- → TRUE +-- @ +-- +-- Also note: `->>` will coerce the json value to @text@, regardless of the content. +-- So the JSON object @{"foo": {}}"@ would be returned as the text: @"{\"foo\": {}}"@. +json :: Typeable a => Json.ParseT ErrorTree Identity a -> Decoder a +json parser = Decoder $ PG.fieldWith $ \field bytes -> do + val <- PG.fromField @Json.Value field bytes + case Json.parseValue parser val of + Left err -> + PG.returnError + PG.ConversionFailed + field + (err & Json.parseErrorTree "Cannot decode jsonb column" & prettyErrorTree & textToString) + Right a -> pure a + +-- | Parse fields out of a nullable json value returned from the database. +-- +-- ATTN: The whole json record has to be transferred before it is parsed, +-- so if you only need a tiny bit of it, use `->` and `->>` in your SQL statement +-- and return only the fields you need from the query. +-- +-- In that case pay attention to NULL though: +-- +-- @ +-- SELECT '{"foo": {}}'::jsonb->>'foo' IS NULL +-- → TRUE +-- @ +-- +-- Also note: `->>` will coerce the json value to @text@, regardless of the content. +-- So the JSON object @{"foo": {}}"@ would be returned as the text: @"{\"foo\": {}}"@. +jsonMay :: Typeable a => Json.ParseT ErrorTree Identity a -> Decoder (Maybe a) +jsonMay parser = Decoder $ PG.fieldWith $ \field bytes -> do + val <- PG.fromField @(Maybe Json.Value) field bytes + case Json.parseValue parser <$> val of + Nothing -> pure Nothing + Just (Left err) -> + PG.returnError + PG.ConversionFailed + field + (err & Json.parseErrorTree "Cannot decode jsonb column" & prettyErrorTree & textToString) + Just (Right a) -> pure (Just a) diff --git a/users/Profpatsch/my-prelude/src/Postgres/MonadPostgres.hs b/users/Profpatsch/my-prelude/src/Postgres/MonadPostgres.hs new file mode 100644 index 000000000000..45c94b2009ca --- /dev/null +++ b/users/Profpatsch/my-prelude/src/Postgres/MonadPostgres.hs @@ -0,0 +1,583 @@ +{-# LANGUAGE DeriveAnyClass #-} +{-# LANGUAGE QuasiQuotes #-} +{-# LANGUAGE TemplateHaskell #-} +{-# OPTIONS_GHC -Wno-orphans #-} + +module Postgres.MonadPostgres where + +import AtLeast (AtLeast) +import Control.Exception +import Control.Monad.Except +import Control.Monad.Logger (MonadLogger, logDebug, logWarn) +import Control.Monad.Reader (MonadReader (ask), ReaderT (..)) +import Control.Monad.Trans.Resource +import Data.Aeson (FromJSON) +import Data.Error.Tree +import Data.Int (Int64) +import Data.Kind (Type) +import Data.List qualified as List +import Data.Pool (Pool) +import Data.Pool qualified as Pool +import Data.Text qualified as Text +import Data.Typeable (Typeable) +import Database.PostgreSQL.Simple (Connection, FormatError, FromRow, Query, QueryError, ResultError, SqlError, ToRow) +import Database.PostgreSQL.Simple qualified as PG +import Database.PostgreSQL.Simple qualified as Postgres +import Database.PostgreSQL.Simple.FromRow qualified as PG +import Database.PostgreSQL.Simple.ToField (ToField) +import Database.PostgreSQL.Simple.ToRow (ToRow (toRow)) +import Database.PostgreSQL.Simple.Types (Query (..)) +import GHC.Records (HasField (..)) +import Label +import OpenTelemetry.Trace.Core qualified as Otel hiding (inSpan, inSpan') +import OpenTelemetry.Trace.Monad qualified as Otel +import PossehlAnalyticsPrelude +import Postgres.Decoder +import Postgres.Decoder qualified as Dec +import Pretty (showPretty) +import Seconds +import System.Exit (ExitCode (..)) +import Tool +import UnliftIO (MonadUnliftIO (withRunInIO)) +import UnliftIO.Process qualified as Process +import UnliftIO.Resource qualified as Resource +import Prelude hiding (span) + +-- | Postgres queries/commands that can be executed within a running transaction. +-- +-- These are implemented with the @postgresql-simple@ primitives of the same name +-- and will behave the same unless othewise documented. +class (Monad m) => MonadPostgres (m :: Type -> Type) where + -- | Execute an INSERT, UPDATE, or other SQL query that is not expected to return results. + + -- Returns the number of rows affected. + execute :: (ToRow params, Typeable params) => Query -> params -> Transaction m (Label "numberOfRowsAffected" Natural) + + -- | Execute an INSERT, UPDATE, or other SQL query that is not expected to return results. Does not take parameters. + + -- Returns the number of rows affected. + execute_ :: Query -> Transaction m (Label "numberOfRowsAffected" Natural) + + -- | Execute a multi-row INSERT, UPDATE, or other SQL query that is not expected to return results. + -- + -- Returns the number of rows affected. If the list of parameters is empty, this function will simply return 0 without issuing the query to the backend. If this is not desired, consider using the 'PG.Values' constructor instead. + executeMany :: (ToRow params, Typeable params) => Query -> [params] -> Transaction m (Label "numberOfRowsAffected" Natural) + + -- | Execute INSERT ... RETURNING, UPDATE ... RETURNING, or other SQL query that accepts multi-row input and is expected to return results. Note that it is possible to write query conn "INSERT ... RETURNING ..." ... in cases where you are only inserting a single row, and do not need functionality analogous to 'executeMany'. + -- + -- If the list of parameters is empty, this function will simply return [] without issuing the query to the backend. If this is not desired, consider using the 'PG.Values' constructor instead. + executeManyReturningWith :: (ToRow q) => Query -> [q] -> Decoder r -> Transaction m [r] + + -- | Run a query, passing parameters and result row parser. + queryWith :: (PG.ToRow params, Typeable params, Typeable r) => PG.Query -> params -> Decoder r -> Transaction m [r] + + -- | Run a query without any parameters and result row parser. + queryWith_ :: (Typeable r) => PG.Query -> Decoder r -> Transaction m [r] + + -- | Run a query, passing parameters, and fold over the resulting rows. + -- + -- This doesn’t have to realize the full list of results in memory, + -- rather results are streamed incrementally from the database. + -- + -- When dealing with small results, it may be simpler (and perhaps faster) to use query instead. + -- + -- This fold is _not_ strict. The stream consumer is responsible for forcing the evaluation of its result to avoid space leaks. + -- + -- If you can, prefer aggregating in the database itself. + foldRows :: + (FromRow row, ToRow params, Typeable row, Typeable params) => + Query -> + params -> + a -> + (a -> row -> Transaction m a) -> + Transaction m a + + -- | Run a given transaction in a transaction block, rolling back the transaction + -- if any exception (postgres or Haskell Exception) is thrown during execution. + -- + -- Re-throws the exception. + -- + -- Don’t do any long-running things on the Haskell side during a transaction, + -- because it will block a database connection and potentially also lock + -- database tables from being written or read by other clients. + -- + -- Nonetheless, try to push transactions as far out to the handlers as possible, + -- don’t do something like @runTransaction $ query …@, because it will lead people + -- to accidentally start nested transactions (the inner transaction is run on a new connections, + -- thus can’t see any changes done by the outer transaction). + -- Only handlers should run transactions. + runTransaction :: Transaction m a -> m a + +-- | Run a query, passing parameters. +query :: forall m params r. (PG.ToRow params, PG.FromRow r, Typeable params, Typeable r, MonadPostgres m) => PG.Query -> params -> Transaction m [r] +query qry params = queryWith qry params (Decoder PG.fromRow) + +-- | Run a query without any parameters. +query_ :: forall m r. (Typeable r, PG.FromRow r, MonadPostgres m) => PG.Query -> Transaction m [r] +query_ qry = queryWith_ qry (Decoder PG.fromRow) + +-- TODO: implement via fold, so that the result doesn’t have to be realized in memory +querySingleRow :: + ( MonadPostgres m, + ToRow qParams, + Typeable qParams, + FromRow a, + Typeable a, + MonadThrow m + ) => + Query -> + qParams -> + Transaction m a +querySingleRow qry params = do + query qry params >>= ensureSingleRow + +-- TODO: implement via fold, so that the result doesn’t have to be realized in memory +querySingleRowMaybe :: + ( MonadPostgres m, + ToRow qParams, + Typeable qParams, + FromRow a, + Typeable a, + MonadThrow m + ) => + Query -> + qParams -> + Transaction m (Maybe a) +querySingleRowMaybe qry params = do + rows <- query qry params + case rows of + [] -> pure Nothing + [one] -> pure (Just one) + -- TODO: Should we MonadThrow this here? It’s really an implementation detail of MonadPostgres + -- that a database function can error out, should probably handled by the instances. + more -> throwM $ SingleRowError {numberOfRowsReturned = (List.length more)} + +ensureSingleRow :: (MonadThrow m) => [a] -> m a +ensureSingleRow = \case + -- TODO: Should we MonadThrow this here? It’s really an implementation detail of MonadPostgres + -- that a database function can error out, should probably handled by the instances. + [] -> throwM (SingleRowError {numberOfRowsReturned = 0}) + [one] -> pure one + more -> + throwM $ + SingleRowError + { numberOfRowsReturned = + -- TODO: this is VERY bad, because it requires to parse the full database output, even if there’s 10000000000 elements + List.length more + } + +newtype Transaction m a = Transaction {unTransaction :: (ReaderT Connection m a)} + deriving newtype + ( Functor, + Applicative, + Monad, + MonadThrow, + MonadLogger, + MonadIO, + MonadUnliftIO, + MonadTrans, + Otel.MonadTracer + ) + +runTransaction' :: Connection -> Transaction m a -> m a +runTransaction' conn transaction = runReaderT transaction.unTransaction conn + +-- | [Resource Pool](http://hackage.haskell.org/package/resource-pool-0.2.3.2/docs/Data-Pool.html) configuration. +data PoolingInfo = PoolingInfo + { -- | Minimal amount of resources that are + -- always available. + numberOfStripes :: AtLeast 1 Int, + -- | Time after which extra resources + -- (above minimum) can stay in the pool + -- without being used. + unusedResourceOpenTime :: Seconds, + -- | Max number of resources that can be + -- in the Pool at any time + maxOpenResourcesPerStripe :: AtLeast 1 Int + } + deriving stock (Generic, Eq, Show) + deriving anyclass (FromJSON) + +initMonadPostgres :: + (Text -> IO ()) -> + -- | Info describing the connection to the Postgres DB + Postgres.ConnectInfo -> + -- | Configuration info for pooling attributes + PoolingInfo -> + -- | Created Postgres connection pool + ResourceT IO (Pool Postgres.Connection) +initMonadPostgres logInfoFn connectInfo poolingInfo = do + (_releaseKey, connPool) <- + Resource.allocate + (logInfoFn "Creating Postgres Connection Pool" >> createPGConnPool) + (\pool -> logInfoFn "Destroying Postgres Connection Pool" >> destroyPGConnPool pool) + pure connPool + where + -- \| Create a Postgres connection pool + createPGConnPool :: + IO (Pool Postgres.Connection) + createPGConnPool = + Pool.createPool + poolCreateResource + poolfreeResource + poolingInfo.numberOfStripes.unAtLeast + (poolingInfo.unusedResourceOpenTime & secondsToNominalDiffTime) + (poolingInfo.maxOpenResourcesPerStripe.unAtLeast) + where + poolCreateResource = Postgres.connect connectInfo + poolfreeResource = Postgres.close + + -- \| Destroy a Postgres connection pool + destroyPGConnPool :: + -- \| Pool to be destroyed + (Pool Postgres.Connection) -> + IO () + destroyPGConnPool p = Pool.destroyAllResources p + +-- | Catch any Postgres exception that gets thrown, +-- print the query that was run and the query parameters, +-- then rethrow inside an 'Error'. +handlePGException :: + forall a params tools m. + (ToRow params, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool) => + tools -> + Text -> + Query -> + -- | Depending on whether we used `format` or `formatMany`. + Either params [params] -> + IO a -> + Transaction m a +handlePGException tools queryType query' params io = do + withRunInIO $ \unliftIO -> + io + `catches` [ Handler $ unliftIO . logQueryException @SqlError, + Handler $ unliftIO . logQueryException @QueryError, + Handler $ unliftIO . logQueryException @ResultError, + Handler $ unliftIO . logFormatException + ] + where + -- TODO: use throwInternalError here (after pulling it into the MonadPostgres class) + throwAsError = unwrapIOError . Left . newError + throwErr err = liftIO $ throwAsError $ prettyErrorTree $ nestedMultiError "A Postgres query failed" err + logQueryException :: (Exception e) => e -> Transaction m a + logQueryException exc = do + formattedQuery <- case params of + Left one -> pgFormatQuery' tools query' one + Right many -> pgFormatQueryMany' tools query' many + throwErr + ( singleError [fmt|Query Type: {queryType}|] + :| [ nestedError "Exception" (exc & showPretty & newError & singleError), + nestedError "Query" (formattedQuery & newError & singleError) + ] + ) + logFormatException :: FormatError -> Transaction m a + logFormatException fe = throwErr (fe & showPretty & newError & singleError & singleton) + +-- | Perform a Postgres action within a transaction +withPGTransaction :: + -- | Postgres connection pool to be used for the action + (Pool Postgres.Connection) -> + -- | DB-action to be performed + (Postgres.Connection -> IO a) -> + -- | Result of the DB-action + IO a +withPGTransaction connPool f = + Pool.withResource + connPool + (\conn -> Postgres.withTransaction conn (f conn)) + +runPGTransactionImpl :: (MonadUnliftIO m) => m (Pool Postgres.Connection) -> Transaction m a -> m a +{-# INLINE runPGTransactionImpl #-} +runPGTransactionImpl zoom (Transaction transaction) = do + pool <- zoom + withRunInIO $ \unliftIO -> + withPGTransaction pool $ \conn -> do + unliftIO $ runReaderT transaction conn + +executeImpl :: + (ToRow params, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool, Otel.MonadTracer m) => + m tools -> + m DebugLogDatabaseQueries -> + Query -> + params -> + Transaction m (Label "numberOfRowsAffected" Natural) +{-# INLINE executeImpl #-} +executeImpl zoomTools zoomDebugLogDatabaseQueries qry params = + Otel.inSpan' "Postgres Query (execute)" Otel.defaultSpanArguments $ \span -> do + tools <- lift @Transaction zoomTools + logDatabaseQueries <- lift @Transaction zoomDebugLogDatabaseQueries + traceQueryIfEnabled tools span logDatabaseQueries qry (HasSingleParam params) + conn <- Transaction ask + PG.execute conn qry params + & handlePGException tools "execute" qry (Left params) + >>= toNumberOfRowsAffected "executeImpl" + +executeImpl_ :: + (MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool, Otel.MonadTracer m) => + m tools -> + m DebugLogDatabaseQueries -> + Query -> + Transaction m (Label "numberOfRowsAffected" Natural) +{-# INLINE executeImpl_ #-} +executeImpl_ zoomTools zoomDebugLogDatabaseQueries qry = + Otel.inSpan' "Postgres Query (execute)" Otel.defaultSpanArguments $ \span -> do + tools <- lift @Transaction zoomTools + logDatabaseQueries <- lift @Transaction zoomDebugLogDatabaseQueries + traceQueryIfEnabled @() tools span logDatabaseQueries qry HasNoParams + conn <- Transaction ask + PG.execute_ conn qry + & handlePGException tools "execute_" qry (Left ()) + >>= toNumberOfRowsAffected "executeImpl_" + +executeManyImpl :: + (ToRow params, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool, Otel.MonadTracer m) => + m tools -> + m DebugLogDatabaseQueries -> + Query -> + [params] -> + Transaction m (Label "numberOfRowsAffected" Natural) +executeManyImpl zoomTools zoomDebugLogDatabaseQueries qry params = + Otel.inSpan' "Postgres Query (execute)" Otel.defaultSpanArguments $ \span -> do + tools <- lift @Transaction zoomTools + logDatabaseQueries <- lift @Transaction zoomDebugLogDatabaseQueries + traceQueryIfEnabled tools span logDatabaseQueries qry (HasMultiParams params) + conn <- Transaction ask + PG.executeMany conn qry params + & handlePGException tools "executeMany" qry (Right params) + >>= toNumberOfRowsAffected "executeManyImpl" + +toNumberOfRowsAffected :: (MonadIO m) => Text -> Int64 -> m (Label "numberOfRowsAffected" Natural) +toNumberOfRowsAffected functionName i64 = + i64 + & intToNatural + & annotate [fmt|{functionName}: postgres returned a negative number of rows affected: {i64}|] + -- we throw this directly in IO here, because we don’t want to e.g. have to propagate MonadThrow through user code (it’s an assertion) + & unwrapIOError + & liftIO + <&> label @"numberOfRowsAffected" + +executeManyReturningWithImpl :: + (ToRow params, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool, Otel.MonadTracer m) => + m tools -> + m DebugLogDatabaseQueries -> + Query -> + [params] -> + Decoder r -> + Transaction m [r] +{-# INLINE executeManyReturningWithImpl #-} +executeManyReturningWithImpl zoomTools zoomDebugLogDatabaseQueries qry params (Decoder fromRow) = do + Otel.inSpan' "Postgres Query (execute)" Otel.defaultSpanArguments $ \span -> do + tools <- lift @Transaction zoomTools + logDatabaseQueries <- lift @Transaction zoomDebugLogDatabaseQueries + traceQueryIfEnabled tools span logDatabaseQueries qry (HasMultiParams params) + conn <- Transaction ask + PG.returningWith fromRow conn qry params + & handlePGException tools "executeManyReturning" qry (Right params) + +foldRowsImpl :: + (FromRow row, ToRow params, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool) => + m tools -> + Query -> + params -> + a -> + (a -> row -> Transaction m a) -> + Transaction m a +{-# INLINE foldRowsImpl #-} +foldRowsImpl zoomTools qry params accumulator f = do + conn <- Transaction ask + tools <- lift @Transaction zoomTools + withRunInIO + ( \runInIO -> + do + PG.fold + conn + qry + params + accumulator + (\acc row -> runInIO $ f acc row) + & handlePGException tools "fold" qry (Left params) + & runInIO + ) + +pgFormatQueryNoParams' :: + (MonadIO m, MonadLogger m, HasField "pgFormat" tools Tool) => + tools -> + Query -> + Transaction m Text +pgFormatQueryNoParams' tools q = + lift $ pgFormatQueryByteString tools q.fromQuery + +pgFormatQuery :: (ToRow params, MonadIO m) => Query -> params -> Transaction m ByteString +pgFormatQuery qry params = Transaction $ do + conn <- ask + liftIO $ PG.formatQuery conn qry params + +pgFormatQueryMany :: (MonadIO m, ToRow params) => Query -> [params] -> Transaction m ByteString +pgFormatQueryMany qry params = Transaction $ do + conn <- ask + liftIO $ PG.formatMany conn qry params + +queryWithImpl :: + (ToRow params, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool, Otel.MonadTracer m) => + m tools -> + m DebugLogDatabaseQueries -> + Query -> + params -> + Decoder r -> + Transaction m [r] +{-# INLINE queryWithImpl #-} +queryWithImpl zoomTools zoomDebugLogDatabaseQueries qry params (Decoder fromRow) = do + Otel.inSpan' "Postgres Query (execute)" Otel.defaultSpanArguments $ \span -> do + tools <- lift @Transaction zoomTools + logDatabaseQueries <- lift @Transaction zoomDebugLogDatabaseQueries + traceQueryIfEnabled tools span logDatabaseQueries qry (HasSingleParam params) + conn <- Transaction ask + PG.queryWith fromRow conn qry params + & handlePGException tools "query" qry (Left params) + +queryWithImpl_ :: (MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool) => m tools -> Query -> Decoder r -> Transaction m [r] +{-# INLINE queryWithImpl_ #-} +queryWithImpl_ zoomTools qry (Decoder fromRow) = do + tools <- lift @Transaction zoomTools + conn <- Transaction ask + liftIO (PG.queryWith_ fromRow conn qry) + & handlePGException tools "query" qry (Left ()) + +pgQuery :: (ToRow params, FromRow r, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool) => tools -> Query -> params -> Transaction m [r] +pgQuery tools qry params = do + conn <- Transaction ask + PG.query conn qry params + & handlePGException tools "query" qry (Left params) + +pgQuery_ :: (FromRow r, MonadUnliftIO m, MonadLogger m, HasField "pgFormat" tools Tool) => tools -> Query -> Transaction m [r] +pgQuery_ tools qry = do + conn <- Transaction ask + PG.query_ conn qry + & handlePGException tools "query_" qry (Left ()) + +data SingleRowError = SingleRowError + { -- | How many columns were actually returned by the query + numberOfRowsReturned :: Int + } + deriving stock (Show) + +instance Exception SingleRowError where + displayException (SingleRowError {..}) = [fmt|Single row expected from SQL query result, {numberOfRowsReturned} rows were returned instead."|] + +pgFormatQuery' :: (MonadIO m, ToRow params, MonadLogger m, HasField "pgFormat" tools Tool) => tools -> Query -> params -> Transaction m Text +pgFormatQuery' tools q p = + pgFormatQuery q p + >>= lift . pgFormatQueryByteString tools + +pgFormatQueryMany' :: (MonadIO m, ToRow params, MonadLogger m, HasField "pgFormat" tools Tool) => tools -> Query -> [params] -> Transaction m Text +pgFormatQueryMany' tools q p = + pgFormatQueryMany q p + >>= lift . pgFormatQueryByteString tools + +-- | Read the executable name "pg_format" +postgresToolsParser :: ToolParserT IO (Label "pgFormat" Tool) +postgresToolsParser = label @"pgFormat" <$> readTool "pg_format" + +pgFormatQueryByteString :: (MonadIO m, MonadLogger m, HasField "pgFormat" tools Tool) => tools -> ByteString -> m Text +pgFormatQueryByteString tools queryBytes = do + do + (exitCode, stdout, stderr) <- + Process.readProcessWithExitCode + tools.pgFormat.toolPath + ["-"] + (queryBytes & bytesToTextUtf8Lenient & textToString) + case exitCode of + ExitSuccess -> pure (stdout & stringToText) + ExitFailure status -> do + $logWarn [fmt|pg_format failed with status {status} while formatting the query, using original query string. Is there a syntax error?|] + $logDebug + ( prettyErrorTree + ( nestedMultiError + "pg_format output" + ( nestedError "stdout" (singleError (stdout & stringToText & newError)) + :| [(nestedError "stderr" (singleError (stderr & stringToText & newError)))] + ) + ) + ) + $logDebug [fmt|pg_format stdout: stderr|] + pure (queryBytes & bytesToTextUtf8Lenient) + +data DebugLogDatabaseQueries + = -- | Do not log the database queries + DontLogDatabaseQueries + | -- | Log the database queries as debug output; + LogDatabaseQueries + | -- | Log the database queries as debug output and additionally the EXPLAIN output (from the query analyzer, not the actual values after execution cause that’s a bit harder to do) + LogDatabaseQueriesAndExplain + deriving stock (Show, Enum, Bounded) + +data HasQueryParams param + = HasNoParams + | HasSingleParam param + | HasMultiParams [param] + +-- | Log the postgres query depending on the given setting +traceQueryIfEnabled :: + ( ToRow params, + MonadUnliftIO m, + MonadLogger m, + HasField "pgFormat" tools Tool, + Otel.MonadTracer m + ) => + tools -> + Otel.Span -> + DebugLogDatabaseQueries -> + Query -> + HasQueryParams params -> + Transaction m () +traceQueryIfEnabled tools span logDatabaseQueries qry params = do + -- In case we have query logging enabled, we want to do that + let formattedQuery = case params of + HasNoParams -> pgFormatQueryNoParams' tools qry + HasSingleParam p -> pgFormatQuery' tools qry p + HasMultiParams ps -> pgFormatQueryMany' tools qry ps + let doLog errs = + Otel.addAttributes + span + $ ( ("postgres.query", Otel.toAttribute @Text errs.query) + : ( errs.explain + & foldMap + ( \ex -> + [("postgres.explain", Otel.toAttribute @Text ex)] + ) + ) + ) + let doExplain = do + q <- formattedQuery + Otel.inSpan "Postgres EXPLAIN Query" Otel.defaultSpanArguments $ do + queryWithImpl_ + (pure tools) + ( "EXPLAIN " + <> ( + -- TODO: this is not nice, but the only way to get the `executeMany` form to work with this + -- because we need the query with all elements already interpolated. + Query (q & textToBytesUtf8) + ) + ) + (Dec.fromField @Text) + <&> Text.intercalate "\n" + case logDatabaseQueries of + DontLogDatabaseQueries -> pure () + LogDatabaseQueries -> do + q <- formattedQuery + doLog (T2 (label @"query" q) (label @"explain" Nothing)) + LogDatabaseQueriesAndExplain -> do + q <- formattedQuery + -- XXX: stuff like `CREATE SCHEMA` cannot be EXPLAINed, so we should catch exceptions here + -- and just ignore anything that errors (if it errors because of a problem with the query, it would have been caught by the query itself. + ex <- doExplain + doLog (T2 (label @"query" q) (label @"explain" (Just ex))) + +instance (ToField t1) => ToRow (Label l1 t1) where + toRow t2 = toRow $ PG.Only $ getField @l1 t2 + +instance (ToField t1, ToField t2) => ToRow (T2 l1 t1 l2 t2) where + toRow t2 = toRow (getField @l1 t2, getField @l2 t2) + +instance (ToField t1, ToField t2, ToField t3) => ToRow (T3 l1 t1 l2 t2 l3 t3) where + toRow t3 = toRow (getField @l1 t3, getField @l2 t3, getField @l3 t3) diff --git a/users/Profpatsch/my-prelude/src/Seconds.hs b/users/Profpatsch/my-prelude/src/Seconds.hs new file mode 100644 index 000000000000..8d05f30be8c3 --- /dev/null +++ b/users/Profpatsch/my-prelude/src/Seconds.hs @@ -0,0 +1,55 @@ +module Seconds where + +import Data.Aeson (FromJSON) +import Data.Aeson qualified as Json +import Data.Aeson.Types (FromJSON (parseJSON)) +import Data.Scientific +import Data.Time (NominalDiffTime) +import FieldParser +import FieldParser qualified as Field +import GHC.Natural (naturalToInteger) +import PossehlAnalyticsPrelude + +-- | A natural number of seconds. +newtype Seconds = Seconds {unSeconds :: Natural} + deriving stock (Eq, Show) + +-- | Parse a decimal number as a number of seconds +textToSeconds :: FieldParser Text Seconds +textToSeconds = Seconds <$> Field.decimalNatural + +scientificToSeconds :: FieldParser Scientific Seconds +scientificToSeconds = + ( Field.boundedScientificIntegral @Int "Number of seconds" + >>> Field.integralToNatural + ) + & rmap Seconds + +-- Microseconds, represented internally with a 64 bit Int +newtype MicrosecondsInt = MicrosecondsInt {unMicrosecondsInt :: Int} + deriving stock (Eq, Show) + +-- | Try to fit a number of seconds into a MicrosecondsInt +secondsToMicrosecondsInt :: FieldParser Seconds MicrosecondsInt +secondsToMicrosecondsInt = + lmap + (\sec -> naturalToInteger sec.unSeconds * 1_000_000) + (Field.bounded "Could not fit into an Int after multiplying with 1_000_000 (seconds to microseconds)") + & rmap MicrosecondsInt + +secondsToNominalDiffTime :: Seconds -> NominalDiffTime +secondsToNominalDiffTime sec = + sec.unSeconds + & naturalToInteger + & fromInteger @NominalDiffTime + +instance FromJSON Seconds where + parseJSON = Field.toParseJSON jsonNumberToSeconds + +-- | Parse a json number as a number of seconds. +jsonNumberToSeconds :: FieldParser' Error Json.Value Seconds +jsonNumberToSeconds = Field.jsonNumber >>> scientificToSeconds + +-- | Return the number of seconds in a week +secondsInAWeek :: Seconds +secondsInAWeek = Seconds (3600 * 24 * 7) diff --git a/users/Profpatsch/my-prelude/src/Test.hs b/users/Profpatsch/my-prelude/src/Test.hs new file mode 100644 index 000000000000..862ee16c255d --- /dev/null +++ b/users/Profpatsch/my-prelude/src/Test.hs @@ -0,0 +1,115 @@ +{-# LANGUAGE LambdaCase #-} + +{- Generate Test suites. + +Restricted version of hspec, introduction: http://hspec.github.io/getting-started.html +-} +module Test + ( Spec, + runTest, + testMain, + + -- * Structure + describe, + it, + + -- * Expectations + Expectation, + testOk, + testErr, + shouldBe, + shouldNotBe, + shouldSatisfy, + shouldNotSatisfy, + + -- * Setup & Teardown (hooks http://hspec.github.io/writing-specs.html#using-hooks) + before, + before_, + beforeWith, + beforeAll, + beforeAll_, + beforeAllWith, + after, + after_, + afterAll, + afterAll_, + around, + around_, + aroundWith, + aroundAll, + aroundAllWith, + + -- * Common helpful predicates (use with 'shouldSatisfy') + isRight, + isLeft, + + -- * Pretty printing of errors + errColored, + module Pretty, + ) +where + +-- export more expectations if needed + +import Data.Either + ( isLeft, + isRight, + ) +import Pretty +import Test.Hspec + ( Expectation, + HasCallStack, + Spec, + after, + afterAll, + afterAll_, + after_, + around, + aroundAll, + aroundAllWith, + aroundWith, + around_, + before, + beforeAll, + beforeAllWith, + beforeAll_, + beforeWith, + before_, + describe, + hspec, + it, + ) +import Test.Hspec.Expectations.Pretty + ( expectationFailure, + shouldBe, + shouldNotBe, + shouldNotSatisfy, + shouldSatisfy, + ) + +-- | Run a test directly (e.g. from the repl) +runTest :: Spec -> IO () +runTest = hspec + +-- | Run a testsuite +testMain :: + -- | Name of the test suite + String -> + -- | The tests in this test module + Spec -> + IO () +testMain testSuiteName tests = hspec $ describe testSuiteName tests + +-- | test successful +testOk :: Expectation +testOk = pure () + +-- | Abort the test with an error message. +-- If you want to display a Haskell type, use `errColored`. +testErr :: HasCallStack => String -> Expectation +testErr = expectationFailure + +-- | Display a list of 'Err's as a colored error message +-- and abort the test. +errColored :: [Pretty.Err] -> Expectation +errColored = testErr . Pretty.prettyErrs diff --git a/users/Profpatsch/my-prelude/src/Tool.hs b/users/Profpatsch/my-prelude/src/Tool.hs new file mode 100644 index 000000000000..066f68bbe0df --- /dev/null +++ b/users/Profpatsch/my-prelude/src/Tool.hs @@ -0,0 +1,75 @@ +{-# LANGUAGE QuasiQuotes #-} + +module Tool where + +import Data.Error.Tree +import Label +import PossehlAnalyticsPrelude +import System.Environment qualified as Env +import System.Exit qualified as Exit +import System.FilePath ((</>)) +import System.Posix qualified as Posix +import ValidationParseT + +data Tool = Tool + { -- | absolute path to the executable + toolPath :: FilePath + } + deriving stock (Show) + +-- | Reads all tools from the @toolsEnvVar@ variable or aborts. +readTools :: + Label "toolsEnvVar" Text -> + -- | Parser for Tools we bring with us at build time. + -- + -- These are executables that we need available, and that we have to ship with the distribution of @pa-cli@. + ToolParserT IO tools -> + IO tools +readTools env toolParser = + Env.lookupEnv (env.toolsEnvVar & textToString) >>= \case + Nothing -> do + Exit.die [fmt|Please set {env.toolsEnvVar} to a directory with all tools we need (see `Tools` in the code).|] + Just toolsDir -> + (Posix.fileExist toolsDir & ifTrueOrErr () [fmt|{env.toolsEnvVar} directory does not exist: {toolsDir}|]) + & thenValidate + ( \() -> + (Posix.getFileStatus toolsDir <&> Posix.isDirectory) + & ifTrueOrErr () [fmt|{env.toolsEnvVar} does not point to a directory: {toolsDir}|] + ) + & thenValidate + (\() -> toolParser.unToolParser toolsDir) + <&> first (errorTree [fmt|Could not find all tools in {env.toolsEnvVar}|]) + >>= \case + Failure err -> Exit.die (err & prettyErrorTree & textToString) + Success t -> pure t + +newtype ToolParserT m a = ToolParserT + { unToolParser :: + FilePath -> + m (Validation (NonEmpty Error) a) + } + deriving + (Functor, Applicative) + via (ValidationParseT FilePath m) + +-- | Given a file path and the name of the tool executable, see whether it is an executable and return its full path. +readTool :: Text -> ToolParserT IO Tool +readTool exeName = ToolParserT $ \toolDir -> do + let toolPath :: FilePath = toolDir </> (exeName & textToString) + let read' = True + let write = False + let exec = True + Posix.fileExist toolPath + & ifTrueOrErr () [fmt|Tool does not exist: {toolPath}|] + & thenValidate + ( \() -> + Posix.fileAccess toolPath read' write exec + & ifTrueOrErr (Tool {..}) [fmt|Tool is not readable/executable: {toolPath}|] + ) + +-- | helper +ifTrueOrErr :: Functor f => a -> Text -> f Bool -> f (Validation (NonEmpty Error) a) +ifTrueOrErr true err io = + io <&> \case + True -> Success true + False -> Failure $ singleton $ newError err diff --git a/users/Profpatsch/my-prelude/src/ValidationParseT.hs b/users/Profpatsch/my-prelude/src/ValidationParseT.hs new file mode 100644 index 000000000000..593b7ebf3918 --- /dev/null +++ b/users/Profpatsch/my-prelude/src/ValidationParseT.hs @@ -0,0 +1,16 @@ +module ValidationParseT where + +import Control.Selective (Selective) +import Data.Functor.Compose (Compose (..)) +import PossehlAnalyticsPrelude + +-- | A simple way to create an Applicative parser that parses from some environment. +-- +-- Use with DerivingVia. Grep codebase for examples. +newtype ValidationParseT env m a = ValidationParseT {unValidationParseT :: env -> m (Validation (NonEmpty Error) a)} + deriving + (Functor, Applicative, Selective) + via ( Compose + ((->) env) + (Compose m (Validation (NonEmpty Error))) + ) |