co-parser.hs

{- stack
  ghci
  --package containers
  --package megaparsec
  --package parser-combinators
  --package mtl
  --package lifted-base
  --package transformers-base
  --package pretty-simple
  --package pqueue
  --package clock
  --ghc-options "-Wall -Wno-name-shadowing"
-}

-- start snippet imports
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE RecordWildCards #-}
module CoInterpreter where

import Control.Concurrent (forkIO, threadDelay)
import Control.Concurrent.MVar.Lifted
import Control.Monad (unless, void, when)
import Control.Monad.Base (MonadBase, liftBase)
import Control.Monad.Combinators.Expr (Operator (..), makeExprParser)
import Control.Monad.Cont (ContT, MonadCont, callCC, runContT)
import Control.Monad.Except (ExceptT, MonadError (..), runExceptT)
import Control.Monad.IO.Class (MonadIO, liftIO)
import Control.Monad.State.Strict (MonadState, StateT, evalStateT)
import qualified Control.Monad.State.Strict as State
import Data.Foldable (for_, traverse_)
import Data.IORef.Lifted
import qualified Data.Map.Strict as Map
import Data.Maybe (fromMaybe)
import qualified Data.PQueue.Prio.Min as PQ
import Data.Time.Clock.POSIX (getPOSIXTime)
import Data.Void (Void)
import System.Clock (Clock (Monotonic), fromNanoSecs, getTime, TimeSpec)
import System.Environment (getArgs, getProgName)
import System.IO (hPutStrLn, stderr)
import Text.Megaparsec hiding (runParser)
import Text.Megaparsec.Char
import qualified Text.Megaparsec.Char.Lexer as L
import Text.Pretty.Simple
  ( CheckColorTty (..),
    OutputOptions (..),
    defaultOutputOptionsNoColor,
    pPrintOpt,
  )
-- end snippet imports

-- start snippet ast-expression
data Expr
  = LNull
  | LBool Bool
  | LStr String
  | LNum Integer
  | Variable Identifier
  | Binary BinOp Expr Expr
  | Call Expr [Expr]
  | Lambda [Identifier] [Stmt]
  | Receive Expr
  deriving (Show, Eq)

type Identifier = String

data BinOp =
    Plus
  | Minus
  | Slash
  | Star
  | Equals
  | NotEquals
  | LessThan
  | GreaterThan
  deriving (Show, Eq)
-- end snippet ast-expression

-- start snippet ast-statement
data Stmt
  = ExprStmt Expr
  | VarStmt Identifier Expr
  | AssignStmt Identifier Expr
  | IfStmt Expr [Stmt]
  | WhileStmt Expr [Stmt]
  | FunctionStmt Identifier [Identifier] [Stmt]
  | ReturnStmt (Maybe Expr)
  | YieldStmt
  | SpawnStmt Expr
  | SendStmt Expr Identifier
  deriving (Show, Eq)

type Program = [Stmt]
-- end snippet ast-statement

-- start snippet basic-parsers
type Parser = Parsec Void String

sc :: Parser ()
sc = L.space space1 lineCmnt blockCmnt
  where
    lineCmnt = L.skipLineComment "//"
    blockCmnt = L.skipBlockComment "/*" "*/"

lexeme :: Parser a -> Parser a
lexeme = L.lexeme sc

symbol :: String -> Parser String
symbol = L.symbol sc

reserved :: String -> Parser ()
reserved w = (lexeme . try) $ string w *> notFollowedBy alphaNumChar

parens, braces :: Parser a -> Parser a
parens = between (symbol "(") (symbol ")")
braces = between (symbol "{") (symbol "}")

semi, identifier, stringLiteral :: Parser String
semi = symbol ";"
identifier = lexeme ((:) <$> letterChar <*> many alphaNumChar)
stringLiteral = char '"' >> manyTill L.charLiteral (char '"') <* sc

integer :: Parser Integer
integer = lexeme (L.signed sc L.decimal)
-- end snippet basic-parsers

-- start snippet parser-utils
runParser :: Parser a -> String -> Either String a
runParser parser code = do
  case parse parser "" code of
    Left err -> Left $ errorBundlePretty err
    Right prog -> Right prog

pPrint :: (MonadIO m, Show a) => a -> m ()
pPrint =
  pPrintOpt CheckColorTty $
    defaultOutputOptionsNoColor
      { outputOptionsIndentAmount = 2,
        outputOptionsCompact = True,
        outputOptionsCompactParens = True
      }
-- end snippet parser-utils

-- start snippet expr-op
operators :: [[Operator Parser Expr]]
operators =
  [ [Prefix $ Receive <$ symbol "<-"],
    [ binary Slash $ symbol "/",
      binary Star $ symbol "*"],
    [ binary Plus $ symbol "+",
      binary Minus $ try (symbol "-" <* notFollowedBy (char '>'))
    ],
    [ binary LessThan $ symbol "<",
      binary GreaterThan $ symbol ">"
    ],
    [ binary Equals $ symbol "==",
      binary NotEquals $ symbol "!="
    ]
  ]
  where
    binary op symP = InfixL $ Binary op <$ symP
-- end snippet expr-op

-- start snippet expr-term
term :: Parser Expr
term = primary >>= call
  where
    call e =
      ( lookAhead (symbol "(")
        >> symbol "("
        >> Call e <$> sepBy expr (symbol ",") <* symbol ")"
        >>= call )
      <|> pure e

    primary = LNull <$ reserved "null"
          <|> LBool True <$ reserved "true"
          <|> LBool False <$ reserved "false"
          <|> LStr <$> stringLiteral
          <|> LNum <$> integer
          <|> Lambda
            <$> (reserved "function" *> parens (sepBy identifier $ symbol ","))
            <*> braces (many stmt)
          <|> Variable <$> identifier
          <|> parens expr
-- end snippet expr-term

-- start snippet expr
expr :: Parser Expr
expr = makeExprParser term operators
-- end snippet expr

-- start snippet stmt
stmt :: Parser Stmt
stmt =
  IfStmt <$> (reserved "if" *> parens expr) <*> braces (many stmt)
    <|> WhileStmt <$> (reserved "while" *> parens expr) <*> braces (many stmt)
    <|> VarStmt <$> (reserved "var" *> identifier) <*> (symbol "=" *> expr <* semi)
    <|> YieldStmt <$ (reserved "yield" <* semi)
    <|> SpawnStmt <$> (reserved "spawn" *> expr <* semi)
    <|> ReturnStmt <$> (reserved "return" *> optional expr <* semi)
    <|> FunctionStmt
      <$> (try $ reserved "function" *> identifier)
      <*> parens (sepBy identifier $ symbol ",")
      <*> braces (many stmt)
    <|> try (AssignStmt <$> identifier <*> (symbol "=" *> expr <* semi))
    <|> try (SendStmt <$> expr <*> (symbol "->" *> identifier <* semi))
    <|> ExprStmt <$> expr <* semi
-- end snippet stmt

-- start snippet program
program :: Parser Program
program = sc *> many stmt <* eof
-- end snippet program