headed-megaparsec (empty) → 0.1

raw patch · 6 files changed

+470/−0 lines, 6 filesdep +basedep +bytestringdep +case-insensitivesetup-changed

Dependencies added: base, bytestring, case-insensitive, containers, megaparsec, parser-combinators, selective, text, unordered-containers

Files

• LICENSE +22/−0
• Setup.hs +2/−0
• headed-megaparsec.cabal +37/−0
• library/HeadedMegaparsec.hs +287/−0
• library/HeadedMegaparsec/Megaparsec.hs +19/−0
• library/HeadedMegaparsec/Prelude.hs +103/−0

@@ -0,0 +1,22 @@+Copyright (c) 2019, Nikita Volkov++Permission is hereby granted, free of charge, to any person+obtaining a copy of this software and associated documentation+files (the "Software"), to deal in the Software without+restriction, including without limitation the rights to use,+copy, modify, merge, publish, distribute, sublicense, and/or sell+copies of the Software, and to permit persons to whom the+Software is furnished to do so, subject to the following+conditions:++The above copyright notice and this permission notice shall be+included in all copies or substantial portions of the Software.++THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR+OTHER DEALINGS IN THE SOFTWARE.

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,37 @@+name: headed-megaparsec+version: 0.1+category: Parsers, Parsing, Megaparsec+synopsis: More informative parser+homepage: https://github.com/nikita-volkov/headed-megaparsec+bug-reports: https://github.com/nikita-volkov/headed-megaparsec/issues+author: Nikita Volkov <nikita.y.volkov@mail.ru>+maintainer: Nikita Volkov <nikita.y.volkov@mail.ru>+copyright: (c) 2019, Nikita Volkov+license: MIT+license-file: LICENSE+build-type: Simple+cabal-version: >=1.10++source-repository head+  type: git+  location: git://github.com/nikita-volkov/headed-megaparsec.git++library+  hs-source-dirs: library+  default-extensions: ApplicativeDo, Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFoldable, DeriveFunctor, DeriveGeneric, DeriveTraversable, DuplicateRecordFields, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples+  default-language: Haskell2010+  exposed-modules:+    HeadedMegaparsec+  other-modules:+    HeadedMegaparsec.Megaparsec+    HeadedMegaparsec.Prelude+  build-depends:+    base >=4.9 && <5,+    bytestring >=0.10 && <0.11,+    case-insensitive >=1.2 && <2,+    containers >=0.6 && <0.7,+    megaparsec >=7 && <9,+    parser-combinators >=1.1 && <1.3,+    selective >=0.3 && <0.4,+    text >=1 && <2,+    unordered-containers >=0.2.10 && <0.3

@@ -0,0 +1,287 @@+module HeadedMegaparsec+(+  -- * Types+  HeadedParsec,+  -- * Execution+  toParsec,+  -- * Transformation+  wrapToHead,+  label,+  dbg,+  filter,+  -- * Construction+  parse,+  endHead,+)+where++import HeadedMegaparsec.Prelude hiding (try, head, tail, filter)+import Control.Applicative.Combinators+import Text.Megaparsec (Parsec, Stream)+import qualified HeadedMegaparsec.Megaparsec as Megaparsec+import qualified Text.Megaparsec as Megaparsec+import qualified Text.Megaparsec.Debug as Megaparsec+import qualified Text.Megaparsec.Char as MegaparsecChar+import qualified Text.Megaparsec.Char.Lexer as MegaparsecLexer+import qualified Data.Text as Text++{- $setup++>>> :set -XApplicativeDo++-}++-- * Types+-------------------------++{-|+Headed parser.++Abstracts over explicit composition between consecutive megaparsec `try` blocks,+providing for better error messages.++With headed parser you don't need to use `try` at all.++==__Examples__++>>> :{+  let+    select :: HeadedParsec Void Text (Maybe [Either Char Int], Maybe Int)+    select = do+      head (string' "select")+      _targets <- optional (head space1 *> targets)+      _limit <- optional (head space1 *> limit)+      return (_targets, _limit)+      where+        targets = sepBy1 target commaSeparator+        target =+          head (Left <$> char '*') <|>+          head (Right <$> Lexer.decimal)+        commaSeparator = head (space *> char ',' *> space)+        limit =+          head (string' "limit" *> space1) *>+          tail Lexer.decimal+    test :: Text -> IO ()+    test = parseTest (toParsec select <* eof)+:}++>>> test "select 1, "+...+unexpected ','+...++>>> test "select limit "+...+unexpected end of input+expecting integer or white space++>>> test "select 1, 2 limit 2"+(Just [Right 1,Right 2],Just 2)++-}+newtype HeadedParsec err strm a = HeadedParsec (Parsec err strm (Either a (Parsec err strm a)))++{-|+A helper required for hacking `dbg`.+-}+data Showable a = Showable String a+++-- * Instances+-------------------------++-- ** Showable+-------------------------++instance Show (Showable a) where+  show (Showable msg _) = msg++-- ** HeadedParsec+-------------------------++instance Functor (HeadedParsec err strm) where+  fmap fn (HeadedParsec p) = HeadedParsec (fmap (bimap fn (fmap fn)) p)++instance (Ord err, Stream strm) => Applicative (HeadedParsec err strm) where+  pure = HeadedParsec . pure . Left+  (<*>) (HeadedParsec p1) (HeadedParsec p2) = HeadedParsec $ do+    junction1 <- p1+    case junction1 of+      Left aToB -> do+        junction2 <- p2+        case junction2 of+          Left a -> return (Left (aToB a))+          Right tailP2 -> return $ Right $ do+            a <- tailP2+            return (aToB a)+      Right tailP1 -> return $ Right $ do+        aToB <- tailP1+        junction2 <- p2+        case junction2 of+          Left a -> return (aToB a)+          Right tailP2 -> do+            a <- tailP2+            return (aToB a)++instance (Ord err, Stream strm) => Selective (HeadedParsec err strm) where+  select (HeadedParsec p1) (HeadedParsec p2) = HeadedParsec $ do+    junction1 <- p1+    case junction1 of+      Left eitherAOrB -> case eitherAOrB of+        Right b -> return (Left b)+        Left a -> do+          junction2 <- p2+          case junction2 of+            Left aToB -> return (Left (aToB a))+            Right tailP2 -> return (Right (fmap ($ a) tailP2))+      Right tailP1 -> return $ Right $ do+        eitherAOrB <- tailP1+        case eitherAOrB of+          Right b -> return b+          Left a -> do+            junction2 <- p2+            case junction2 of+              Left aToB -> return (aToB a)+              Right tailP2 -> fmap ($ a) tailP2++instance (Ord err, Stream strm) => Monad (HeadedParsec err strm) where+  return = pure+  (>>=) (HeadedParsec p1) k2 = HeadedParsec $ do+    junction1 <- p1+    case junction1 of+      Left a -> case k2 a of HeadedParsec p2 -> p2+      Right tailP1 -> return $ Right $ do+        a <- tailP1+        Megaparsec.contPossibly $ case k2 a of HeadedParsec p2 -> p2++{-|+Alternation is performed only the basis of heads.+Bodies do not participate.+-}+instance (Ord err, Stream strm) => Alternative (HeadedParsec err strm) where+  empty = HeadedParsec empty+  (<|>) (HeadedParsec p1) (HeadedParsec p2) = HeadedParsec (Megaparsec.try p1 <|> p2)++{-|+Alternation is performed only the basis of heads.+Bodies do not participate.+-}+instance (Ord err, Stream strm) => MonadPlus (HeadedParsec err strm) where+  mzero = empty+  mplus = (<|>)++instance (Ord err, Stream strm) => MonadFail (HeadedParsec err strm) where+  fail = HeadedParsec . fail+++-- * Execution+-------------------------++{-|+Convert headed parser into megaparsec parser.+-}+toParsec :: (Ord err, Stream strm) => HeadedParsec err strm a -> Parsec err strm a+toParsec (HeadedParsec p) = Megaparsec.contPossibly p+++-- * Helpers+-------------------------++mapParsec :: (Parsec err1 strm1 (Either res1 (Parsec err1 strm1 res1)) -> Parsec err2 strm2 (Either res2 (Parsec err2 strm2 res2))) -> HeadedParsec err1 strm1 res1 -> HeadedParsec err2 strm2 res2+mapParsec fn (HeadedParsec p) = HeadedParsec (fn p)+++-- * Transformation+-------------------------++{-|+Wrap a parser to be usable as a whole in a head block,+allowing it in effect to be composed with the following parsers into a single `try` when executed,+no matter whether it contains `endHead` or not.+-}+wrapToHead :: (Ord err, Stream strm) => HeadedParsec err strm a -> HeadedParsec err strm a+wrapToHead = mapParsec $ fmap Left . Megaparsec.contPossibly++{-|+Label a headed parser.+Works the same way as megaparsec's `Megaparsec.label`.+-}+label :: (Ord err, Stream strm) => String -> HeadedParsec err strm a -> HeadedParsec err strm a+label label = mapParsec (Megaparsec.label label)++{-|+Make a parser print debugging information when evaluated.+The first parameter is a custom label.++This function is a wrapper around `Megaparsec.dbg`.+It generates two debugging entries: one for head and one for tail.+-}+dbg :: (Ord err, Megaparsec.ShowErrorComponent err, Stream strm, Show a) => String -> HeadedParsec err strm a -> HeadedParsec err strm a+dbg label = mapParsec $ \ p -> do+  Showable _ junction <- Megaparsec.dbg (label <> "/head") (fmap (either (\ a -> Showable (show a) (Left a)) (Showable "<tail parser>" . Right)) p)+  case junction of+    Left a -> return (Left a)+    Right tailP -> return $ Right $ Megaparsec.dbg (label <> "/tail") tailP++{-|+Filter the results of parser based on a predicate,+failing with a parameterized message.+-}+filter :: (Ord err, Stream strm) => (a -> String) -> (a -> Bool) -> HeadedParsec err strm a -> HeadedParsec err strm a+filter err pred = mapParsec $ \ p -> do+  junction <- p+  case junction of+    Left a -> if pred a+      then return (Left a)+      else fail (err a)+    Right tailP -> return $ Right $ do+      a <- tailP+      if pred a+        then return a+        else fail (err a)+++-- *+-------------------------++{-|+Lift a megaparsec parser as a head parser.+-}+head :: (Ord err, Stream strm) => Parsec err strm a -> HeadedParsec err strm a+head = HeadedParsec . fmap Left++{-|+Lift a megaparsec parser as a tail parser.++Composing consecutive tails results in one tail.++Composing consecutive head and tail leaves the head still composable with preceding head.+-}+tail :: (Stream strm) => Parsec err strm a -> HeadedParsec err strm a+tail = HeadedParsec . return . Right++{-|+Lift both head and tail megaparsec parsers, composing their results.+-}+headAndTail :: (Ord err, Stream strm) => (head -> tail -> a) -> Parsec err strm head -> Parsec err strm tail -> HeadedParsec err strm a+headAndTail fn headP tailP = HeadedParsec $ do+  a <- headP+  return $ Right $ do+    b <- tailP+    return (fn a b)++{-|+Lift a megaparsec parser.+-}+parse :: (Ord err, Stream strm) => Parsec err strm a -> HeadedParsec err strm a+parse = head+++-- * Control+-------------------------++{-|+Make all the following parsers compose as tail.+-}+endHead :: (Stream strm) => HeadedParsec err strm ()+endHead = HeadedParsec (return (Right (return ())))

@@ -0,0 +1,19 @@+{-|+Extra megaparsec combinators.+-}+module HeadedMegaparsec.Megaparsec+where++import HeadedMegaparsec.Prelude hiding (try, head, body)+import Text.Megaparsec hiding (some, endBy1, someTill, sepBy1, sepEndBy1)+import Text.Megaparsec.Char+import Control.Applicative.Combinators+import qualified Text.Megaparsec.Char.Lexer as Lexer+++contPossibly :: (Ord err, Stream strm) => Parsec err strm (Either a (Parsec err strm a)) -> Parsec err strm a+contPossibly p = do+  junction <- try p+  case junction of+    Left a -> return a+    Right cont -> cont

@@ -0,0 +1,103 @@+module HeadedMegaparsec.Prelude+( +  module Exports,+  showAsText,+)+where++-- base+-------------------------+import Control.Applicative as Exports+import Control.Arrow as Exports hiding (first, second)+import Control.Category as Exports+import Control.Concurrent as Exports+import Control.Exception as Exports+import Control.Monad as Exports hiding (fail, mapM_, sequence_, forM_, msum, mapM, sequence, forM)+import Control.Monad.IO.Class as Exports+import Control.Monad.Fail as Exports+import Control.Monad.Fix as Exports hiding (fix)+import Control.Monad.ST as Exports+import Data.Bifunctor as Exports+import Data.Bits as Exports+import Data.Bool as Exports+import Data.Char as Exports+import Data.Coerce as Exports+import Data.Complex as Exports+import Data.Data as Exports+import Data.Dynamic as Exports+import Data.Either as Exports+import Data.Fixed as Exports+import Data.Foldable as Exports+import Data.Function as Exports hiding (id, (.))+import Data.Functor as Exports+import Data.Functor.Identity as Exports+import Data.Int as Exports+import Data.IORef as Exports+import Data.Ix as Exports+import Data.List as Exports hiding (sortOn, isSubsequenceOf, uncons, concat, foldr, foldl1, maximum, minimum, product, sum, all, and, any, concatMap, elem, foldl, foldr1, notElem, or, find, maximumBy, minimumBy, mapAccumL, mapAccumR, foldl')+import Data.List.NonEmpty as Exports (NonEmpty(..))+import Data.Maybe as Exports+import Data.Monoid as Exports hiding (Last(..), First(..), (<>))+import Data.Ord as Exports+import Data.Proxy as Exports+import Data.Ratio as Exports+import Data.Semigroup as Exports+import Data.STRef as Exports+import Data.String as Exports+import Data.Traversable as Exports+import Data.Tuple as Exports+import Data.Unique as Exports+import Data.Version as Exports+import Data.Void as Exports+import Data.Word as Exports+import Debug.Trace as Exports+import Foreign.ForeignPtr as Exports+import Foreign.Ptr as Exports+import Foreign.StablePtr as Exports+import Foreign.Storable as Exports hiding (sizeOf, alignment)+import GHC.Conc as Exports hiding (orElse, withMVar, threadWaitWriteSTM, threadWaitWrite, threadWaitReadSTM, threadWaitRead)+import GHC.Exts as Exports (lazy, inline, sortWith, groupWith, IsList(fromList, Item))+import GHC.Generics as Exports (Generic, Generic1)+import GHC.IO.Exception as Exports+import Numeric as Exports+import Prelude as Exports hiding (fail, concat, foldr, mapM_, sequence_, foldl1, maximum, minimum, product, sum, all, and, any, concatMap, elem, foldl, foldr1, notElem, or, mapM, sequence, id, (.))+import System.Environment as Exports+import System.Exit as Exports+import System.IO as Exports+import System.IO.Error as Exports+import System.IO.Unsafe as Exports+import System.Mem as Exports+import System.Mem.StableName as Exports+import System.Timeout as Exports+import Text.ParserCombinators.ReadP as Exports (ReadP, ReadS, readP_to_S, readS_to_P)+import Text.ParserCombinators.ReadPrec as Exports (ReadPrec, readPrec_to_P, readP_to_Prec, readPrec_to_S, readS_to_Prec)+import Text.Printf as Exports (printf, hPrintf)+import Text.Read as Exports (Read(..), readMaybe, readEither)+import Unsafe.Coerce as Exports++-- selective+-------------------------+import Control.Selective as Exports++-- bytestring+-------------------------+import Data.ByteString as Exports (ByteString)++-- text+-------------------------+import Data.Text as Exports (Text)++-- containers+-------------------------+import Data.IntMap.Strict as Exports (IntMap)+import Data.IntSet as Exports (IntSet)+import Data.Map.Strict as Exports (Map)+import Data.Sequence as Exports (Seq)+import Data.Set as Exports (Set)++-- case-insensitive+-------------------------+import Data.CaseInsensitive as Exports (CI, FoldCase)++showAsText :: Show a => a -> Text+showAsText = show >>> fromString