egison-4.1.0: hs-src/Language/Egison/Parser/NonS.hs
{-# LANGUAGE TupleSections #-}
{-# LANGUAGE NamedFieldPuns #-}
{- |
Module : Language.Egison.Parser.NonS
Licence : MIT
This module provides the parser for the new syntax.
-}
module Language.Egison.Parser.NonS
(
-- * Parse a string
parseTopExprs
, parseTopExpr
, parseExprs
, parseExpr
, upperReservedWords
, lowerReservedWords
) where
import Control.Monad.State (get, gets, put)
import Data.Char (isAsciiUpper, isLetter)
import Data.Either (isRight)
import Data.Functor (($>))
import Data.List (groupBy, insertBy)
import Data.Maybe (isJust, isNothing)
import Data.Text (pack)
import Control.Monad.Combinators.Expr
import Text.Megaparsec
import Text.Megaparsec.Char
import qualified Text.Megaparsec.Char.Lexer as L
import Language.Egison.AST hiding (Assoc(..))
import qualified Language.Egison.AST as E
import Language.Egison.RState
parseTopExprs :: String -> RuntimeM (Either String [TopExpr])
parseTopExprs = doParse $ many (L.nonIndented sc topExpr) <* eof
parseTopExpr :: String -> RuntimeM (Either String TopExpr)
parseTopExpr = doParse $ sc >> topExpr <* eof
parseExprs :: String -> RuntimeM (Either String [Expr])
parseExprs = doParse $ many (L.nonIndented sc expr) <* eof
parseExpr :: String -> RuntimeM (Either String Expr)
parseExpr = doParse $ sc >> expr <* eof
--
-- Parser
--
type Parser = ParsecT CustomError String RuntimeM
data CustomError
= IllFormedSection Op Op
| IllFormedDefine
| LastStmtInDoBlock
deriving (Eq, Ord)
instance ShowErrorComponent CustomError where
showErrorComponent (IllFormedSection op op') =
"The operator " ++ info op ++ " must have lower precedence than " ++ info op'
where
info op =
"'" ++ repr op ++ "' [" ++ show (assoc op) ++ " " ++ show (priority op) ++ "]"
showErrorComponent IllFormedDefine =
"Failed to parse the left hand side of definition expression."
showErrorComponent LastStmtInDoBlock =
"The last statement in a 'do' block must be an expression."
doParse :: Parser a -> String -> RuntimeM (Either String a)
doParse p input = do
result <- runParserT p "egison" input
case result of
Left e -> return $ Left (errorBundlePretty e)
Right r -> return $ Right r
--
-- Expressions
--
topExpr :: Parser TopExpr
topExpr = Load <$> (reserved "load" >> stringLiteral)
<|> LoadFile <$> (reserved "loadFile" >> stringLiteral)
<|> Execute <$> (reserved "execute" >> expr)
<|> (reserved "def" >> defineExpr)
<|> infixExpr
<|> Test <$> expr
<?> "toplevel expression"
-- Sort binaryop table on the insertion
addNewOp :: Op -> Bool -> Parser ()
addNewOp newop isPattern | isPattern = do
pstate <- get
put $! pstate { patternOps = insertBy
(\x y -> compare (priority y) (priority x))
newop
(patternOps pstate) }
addNewOp newop _ = do
pstate <- get
put $! pstate { exprOps = insertBy
(\x y -> compare (priority y) (priority x))
newop
(exprOps pstate) }
infixExpr :: Parser TopExpr
infixExpr = do
assoc <- (reserved "infixl" $> E.InfixL)
<|> (reserved "infixr" $> E.InfixR)
<|> (reserved "infix" $> E.InfixN)
isPattern <- isRight <$> eitherP (reserved "expression") (reserved "pattern")
priority <- fromInteger <$> positiveIntegerLiteral
sym <- if isPattern then newPatOp >>= checkP else some opChar >>= check
let newop = Op { repr = sym, priority, assoc, isWedge = False }
addNewOp newop isPattern
return (InfixDecl isPattern newop)
where
check :: String -> Parser String
check ('!':_) = fail $ "cannot declare infix starting with '!'"
check x | x `elem` reservedOp = fail $ show x ++ " cannot be a new infix"
| otherwise = return x
-- Checks if given string is valid for pattern op.
checkP :: String -> Parser String
checkP x | x `elem` reservedPOp = fail $ show x ++ " cannot be a new pattern infix"
| otherwise = return x
reservedOp = [":", ":=", "->"]
reservedPOp = ["&", "|", ":=", "->"]
defineExpr :: Parser TopExpr
defineExpr = do
ops <- gets exprOps
f <- parens (stringToVarWithIndices . repr <$> choice (map (infixLiteral . repr) ops))
<|> varWithIndicesLiteral
args <- many arg
_ <- symbol ":="
body <- expr
case args of
[] -> return (Define f body)
_ -> return (Define f (LambdaExpr args body))
expr :: Parser Expr
expr = do
body <- exprWithoutWhere
bindings <- optional (reserved "where" >> alignSome binding)
return $ case bindings of
Nothing -> body
Just bindings -> LetRecExpr bindings body
exprWithoutWhere :: Parser Expr
exprWithoutWhere = opExpr
-- Expressions that can be the arguments for the operators.
exprInOp :: Parser Expr
exprInOp =
ifExpr
<|> patternMatchExpr
<|> lambdaExpr
<|> lambdaLikeExpr
<|> letExpr
<|> withSymbolsExpr
<|> doExpr
<|> seqExpr
<|> capplyExpr
<|> matcherExpr
<|> algebraicDataMatcherExpr
<|> tensorExpr
<|> functionExpr
<|> refsExpr
<|> atomOrApplyExpr
<?> "expression"
-- Also parses exprInOp
opExpr :: Parser Expr
opExpr = do
ops <- gets exprOps
makeExprParser exprInOp (makeExprTable ops)
makeExprTable :: [Op] -> [[Operator Parser Expr]]
makeExprTable ops =
-- Generate binary operator table from |ops|
map (map toOperator) (groupBy (\x y -> priority x == priority y) ops)
where
-- notFollowedBy (in unary and binary) is necessary for section expression.
unary :: String -> Parser (Expr -> Expr)
unary sym = PrefixExpr <$> try (operator sym <* notFollowedBy (symbol ")"))
binary :: Op -> Parser (Expr -> Expr -> Expr)
binary op = do
-- Operators should be indented than pos1 in order to avoid
-- "1\n-2" (2 topExprs, 1 and -2) to be parsed as "1 - 2".
op <- try (indented >> infixLiteral (repr op) <* notFollowedBy (symbol ")"))
return $ InfixExpr op
toOperator :: Op -> Operator Parser Expr
toOperator op =
case assoc op of
E.InfixL -> InfixL (binary op)
E.InfixR -> InfixR (binary op)
E.InfixN -> InfixN (binary op)
E.Prefix -> Prefix (unary (repr op))
ifExpr :: Parser Expr
ifExpr = reserved "if" >> IfExpr <$> expr <* reserved "then" <*> expr <* reserved "else" <*> expr
patternMatchExpr :: Parser Expr
patternMatchExpr = makeMatchExpr (reserved "match") (MatchExpr BFSMode)
<|> makeMatchExpr (reserved "matchDFS") (MatchExpr DFSMode)
<|> makeMatchExpr (reserved "matchAll") (MatchAllExpr BFSMode)
<|> makeMatchExpr (reserved "matchAllDFS") (MatchAllExpr DFSMode)
<?> "pattern match expression"
where
makeMatchExpr keyword ctor = ctor <$> (keyword >> expr)
<*> (reserved "as" >> expr)
<*> (reserved "with" >> matchClauses1)
-- Parse more than 1 match clauses.
matchClauses1 :: Parser [MatchClause]
matchClauses1 =
-- If the first bar '|' is missing, then it is expected to have only one match clause.
(lookAhead (symbol "|") >> alignSome matchClause) <|> (:[]) <$> matchClauseWithoutBar
where
matchClauseWithoutBar :: Parser MatchClause
matchClauseWithoutBar = (,) <$> pattern <*> (symbol "->" >> expr)
matchClause :: Parser MatchClause
matchClause = (,) <$> (symbol "|" >> pattern) <*> (symbol "->" >> expr)
lambdaExpr :: Parser Expr
lambdaExpr = symbol "\\" >> (
makeMatchLambdaExpr (reserved "match") MatchLambdaExpr
<|> makeMatchLambdaExpr (reserved "matchAll") MatchAllLambdaExpr
<|> try (LambdaExpr <$> some arg <* symbol "->") <*> expr
<|> PatternFunctionExpr <$> tupleOrSome lowerId <*> (symbol "=>" >> pattern))
<?> "lambda or pattern function expression"
where
makeMatchLambdaExpr keyword ctor = do
matcher <- keyword >> reserved "as" >> expr
clauses <- reserved "with" >> matchClauses1
return $ ctor matcher clauses
lambdaLikeExpr :: Parser Expr
lambdaLikeExpr =
(reserved "memoizedLambda" >> MemoizedLambdaExpr <$> tupleOrSome lowerId <*> (symbol "->" >> expr))
<|> (reserved "cambda" >> CambdaExpr <$> lowerId <*> (symbol "->" >> expr))
arg :: Parser (Arg ArgPattern)
arg = InvertedScalarArg <$> (string "*$" >> argPatternAtom)
<|> TensorArg <$> (char '%' >> argPatternAtom)
<|> ScalarArg <$> (char '$' >> argPatternAtom)
<|> TensorArg <$> argPattern
<?> "argument"
argPattern :: Parser ArgPattern
argPattern =
argPatternAtom
argPatternAtom :: Parser ArgPattern
argPatternAtom
= APWildCard <$ symbol "_"
<|> APTuplePat <$> parens (sepBy arg comma)
<|> APPatVar <$> ident
letExpr :: Parser Expr
letExpr = do
binds <- reserved "let" >> oneLiner <|> alignSome binding
body <- reserved "in" >> expr
return $ LetRecExpr binds body
where
oneLiner :: Parser [BindingExpr]
oneLiner = braces $ sepBy binding (symbol ";")
binding :: Parser BindingExpr
binding = do
id <- Left <$> try varWithIndicesLiteral' <|> Right <$> pdAtom
args <- many arg
body <- symbol ":=" >> expr
case (id, args) of
(Left var, []) -> return $ BindWithIndices var body
(Right pdp, []) -> return $ Bind pdp body
(Right pdp, _) -> return $ Bind pdp (LambdaExpr args body)
_ -> error "unreachable"
withSymbolsExpr :: Parser Expr
withSymbolsExpr = WithSymbolsExpr <$> (reserved "withSymbols" >> brackets (sepBy ident comma)) <*> expr
doExpr :: Parser Expr
doExpr = do
stmts <- reserved "do" >> oneLiner <|> alignSome statement
case reverse stmts of
[] -> return $ DoExpr [] (makeApply "return" [])
Bind (PDTuplePat []) expr:_ -> return $ DoExpr (init stmts) expr
_:_ -> customFailure LastStmtInDoBlock
where
statement :: Parser BindingExpr
statement = (reserved "let" >> binding) <|> Bind (PDTuplePat []) <$> expr
oneLiner :: Parser [BindingExpr]
oneLiner = braces $ sepBy statement (symbol ";")
seqExpr :: Parser Expr
seqExpr = SeqExpr <$> (reserved "seq" >> atomExpr) <*> atomExpr
capplyExpr :: Parser Expr
capplyExpr = CApplyExpr <$> (reserved "capply" >> atomExpr) <*> atomExpr
matcherExpr :: Parser Expr
matcherExpr = do
reserved "matcher"
-- Assuming it is unlikely that users want to write matchers with only 1
-- pattern definition, the first '|' (bar) is made indispensable in matcher
-- expression.
MatcherExpr <$> alignSome (symbol "|" >> patternDef)
where
patternDef :: Parser (PrimitivePatPattern, Expr, [(PrimitiveDataPattern, Expr)])
patternDef = do
pp <- ppPattern
returnMatcher <- reserved "as" >> expr <* reserved "with"
datapat <- alignSome (symbol "|" >> dataCases)
return (pp, returnMatcher, datapat)
dataCases :: Parser (PrimitiveDataPattern, Expr)
dataCases = (,) <$> pdPattern <*> (symbol "->" >> expr)
algebraicDataMatcherExpr :: Parser Expr
algebraicDataMatcherExpr = do
reserved "algebraicDataMatcher"
AlgebraicDataMatcherExpr <$> alignSome (symbol "|" >> patternDef)
where
patternDef = indentBlock lowerId atomExpr
tensorExpr :: Parser Expr
tensorExpr =
(reserved "tensor" >> TensorExpr <$> atomExpr <*> atomExpr)
<|> (reserved "generateTensor" >> GenerateTensorExpr <$> atomExpr <*> atomExpr)
<|> (reserved "contract" >> TensorContractExpr <$> atomExpr)
<|> (reserved "tensorMap" >> TensorMapExpr <$> atomExpr <*> atomExpr)
<|> (reserved "tensorMap2" >> TensorMap2Expr <$> atomExpr <*> atomExpr <*> atomExpr)
<|> (reserved "transpose" >> TransposeExpr <$> atomExpr <*> atomExpr)
functionExpr :: Parser Expr
functionExpr = FunctionExpr <$> (reserved "function" >> parens (sepBy ident comma))
refsExpr :: Parser Expr
refsExpr =
(reserved "subrefs" >> SubrefsExpr False <$> atomExpr <*> atomExpr)
<|> (reserved "subrefs!" >> SubrefsExpr True <$> atomExpr <*> atomExpr)
<|> (reserved "suprefs" >> SuprefsExpr False <$> atomExpr <*> atomExpr)
<|> (reserved "suprefs!" >> SuprefsExpr True <$> atomExpr <*> atomExpr)
<|> (reserved "userRefs" >> UserrefsExpr False <$> atomExpr <*> atomExpr)
<|> (reserved "userRefs!" >> UserrefsExpr True <$> atomExpr <*> atomExpr)
collectionExpr :: Parser Expr
collectionExpr = symbol "[" >> betweenOrFromExpr <|> elementsExpr
where
betweenOrFromExpr = do
start <- try (expr <* symbol "..")
end <- optional expr <* symbol "]"
case end of
Just end' -> return $ makeApply "between" [start, end']
Nothing -> return $ makeApply "from" [start]
elementsExpr = CollectionExpr <$> (sepBy expr comma <* symbol "]")
-- Parse an atomic expression starting with '(', which can be:
-- * a tuple
-- * an arbitrary expression wrapped with parenthesis
-- * section
tupleOrParenExpr :: Parser Expr
tupleOrParenExpr = do
elems <- symbol "(" >> try (sepBy expr comma <* symbol ")") <|> (section <* symbol ")")
case elems of
[x] -> return x -- expression wrapped in parenthesis
_ -> return $ TupleExpr elems -- tuple
where
section :: Parser [Expr]
-- Start from right, in order to parse expressions like (-1 +) correctly
section = (:[]) <$> (rightSection <|> leftSection)
-- Sections without the left operand: eg. (+), (+ 1)
leftSection :: Parser Expr
leftSection = do
ops <- gets exprOps
op <- choice $ map (infixLiteral . repr) ops
rarg <- optional expr
case rarg of
-- Disabling for now... (See issue 159)
-- Just (InfixExpr op' _ _)
-- | assoc op' /= InfixR && priority op >= priority op' ->
-- customFailure (IllFormedSection op op')
_ -> return (SectionExpr op Nothing rarg)
-- Sections with the left operand but lacks the right operand: eg. (1 +)
rightSection :: Parser Expr
rightSection = do
ops <- gets exprOps
larg <- opExpr
op <- choice $ map (infixLiteral . repr) ops
case larg of
-- InfixExpr op' _ _
-- | assoc op' /= InfixL && priority op >= priority op' ->
-- customFailure (IllFormedSection op op')
_ -> return (SectionExpr op (Just larg) Nothing)
vectorExpr :: Parser Expr
vectorExpr = VectorExpr <$> between (symbol "[|") (symbol "|]") (sepEndBy expr comma)
hashExpr :: Parser Expr
hashExpr = HashExpr <$> hashBraces (sepEndBy hashElem comma)
where
hashBraces = between (symbol "{|") (symbol "|}")
hashElem = parens $ (,) <$> expr <*> (comma >> expr)
index :: Parser a -> Parser (IndexExpr a)
index p = SupSubscript <$> (string "~_" >> p)
<|> try (char '_' >> subscript)
<|> try (char '~' >> superscript)
<|> try (Userscript <$> (char '|' >> p))
<?> "index"
where
subscript = do
e1 <- p
e2 <- optional (string "..._" >> p)
case e2 of
Nothing -> return $ Subscript e1
Just e2' -> return $ MultiSubscript e1 e2'
superscript = do
e1 <- p
e2 <- optional (string "...~" >> p)
case e2 of
Nothing -> return $ Superscript e1
Just e2' -> return $ MultiSuperscript e1 e2'
atomOrApplyExpr :: Parser Expr
atomOrApplyExpr = do
(func, args) <- indentBlock atomExpr atomExpr
return $ case args of
[] -> func
_ -> ApplyExpr func args
-- (Possibly indexed) atomic expressions
atomExpr :: Parser Expr
atomExpr = do
e <- atomExpr'
override <- isNothing <$> optional (try (string "..." <* lookAhead (index atomExpr')))
indices <- many (index atomExpr')
return $ case indices of
[] -> e
_ -> IndexedExpr override e indices
-- Atomic expressions without index
atomExpr' :: Parser Expr
atomExpr' = anonParamFuncExpr -- must come before |constantExpr|
<|> ConstantExpr <$> constantExpr
<|> FreshVarExpr <$ symbol "#"
<|> VarExpr <$> ident
<|> vectorExpr -- must come before |collectionExpr|
<|> collectionExpr
<|> tupleOrParenExpr
<|> hashExpr
<|> QuoteExpr <$> (char '\'' >> atomExpr') -- must come after |constantExpr|
<|> QuoteSymbolExpr <$> (char '`' >> atomExpr')
<|> AnonParamExpr <$> try (char '%' >> positiveIntegerLiteral)
<?> "atomic expression"
anonParamFuncExpr :: Parser Expr
anonParamFuncExpr = do
n <- try (L.decimal <* char '#') -- No space after the index
body <- atomExpr -- No space after '#'
return $ AnonParamFuncExpr n body
constantExpr :: Parser ConstantExpr
constantExpr = numericExpr
<|> BoolExpr <$> boolLiteral
<|> CharExpr <$> try charLiteral -- try for quoteExpr
<|> StringExpr . pack <$> stringLiteral
<|> SomethingExpr <$ reserved "something"
<|> UndefinedExpr <$ reserved "undefined"
numericExpr :: Parser ConstantExpr
numericExpr = FloatExpr <$> try positiveFloatLiteral
<|> IntegerExpr <$> positiveIntegerLiteral
<?> "numeric expression"
--
-- Pattern
--
pattern :: Parser Pattern
pattern = letPattern
<|> forallPattern
<|> loopPattern
<|> opPattern
<?> "pattern"
letPattern :: Parser Pattern
letPattern =
reserved "let" >> LetPat <$> alignSome binding <*> (reserved "in" >> pattern)
forallPattern :: Parser Pattern
forallPattern =
reserved "forall" >> ForallPat <$> atomPattern <*> atomPattern
loopPattern :: Parser Pattern
loopPattern =
LoopPat <$> (reserved "loop" >> char '$' >> ident) <*> loopRange
<*> atomPattern <*> atomPattern
where
loopRange :: Parser LoopRange
loopRange =
parens $ do start <- expr
ends <- option (defaultEnds start) (try $ comma >> expr)
as <- option WildCard (comma >> pattern)
return $ LoopRange start ends as
defaultEnds s =
makeApply "from"
[makeApply "-'" [s, ConstantExpr (IntegerExpr 1)]]
seqPattern :: Parser Pattern
seqPattern = do
pats <- braces $ sepBy pattern comma
return $ foldr SeqConsPat SeqNilPat pats
opPattern :: Parser Pattern
opPattern = do
ops <- gets patternOps
makeExprParser applyOrAtomPattern (makePatternTable ops)
makePatternTable :: [Op] -> [[Operator Parser Pattern]]
makePatternTable ops =
let ops' = map toOperator ops
in map (map snd) (groupBy (\x y -> fst x == fst y) ops')
where
toOperator :: Op -> (Int, Operator Parser Pattern)
toOperator op = (priority op, infixToOperator binary op)
binary :: Op -> Parser (Pattern -> Pattern -> Pattern)
binary op = do
op <- try (indented >> patInfixLiteral (repr op))
return $ InfixPat op
applyOrAtomPattern :: Parser Pattern
applyOrAtomPattern = (do
(func, args) <- indentBlock (try atomPattern) atomPattern
case (func, args) of
(_, []) -> return func
(InductivePat x [], _) -> return $ InductiveOrPApplyPat x args
_ -> return $ DApplyPat func args)
<|> (do
(func, args) <- indentBlock atomExpr atomPattern
return $ PApplyPat func args)
collectionPattern :: Parser Pattern
collectionPattern = brackets $ do
elems <- sepBy pattern comma
return $ foldr (InfixPat consOp) nilPat elems
where
nilPat = InductivePat "nil" []
consOp = findOpFrom "::" reservedPatternOp
-- (Possibly indexed) atomic pattern
atomPattern :: Parser Pattern
atomPattern = do
pat <- atomPattern'
indices <- many . try $ char '_' >> atomExpr'
return $ case indices of
[] -> pat
_ -> IndexedPat pat indices
-- Atomic pattern without index
atomPattern' :: Parser Pattern
atomPattern' = WildCard <$ symbol "_"
<|> PatVar <$> patVarLiteral
<|> NotPat <$> (symbol "!" >> atomPattern)
<|> ValuePat <$> (char '#' >> atomExpr)
<|> collectionPattern
<|> InductivePat <$> lowerId <*> pure []
<|> VarPat <$> (char '~' >> lowerId)
<|> PredPat <$> (symbol "?" >> atomExpr)
<|> ContPat <$ symbol "..."
<|> makeTupleOrParen pattern TuplePat
<|> seqPattern
<|> LaterPatVar <$ symbol "@"
<?> "atomic pattern"
ppPattern :: Parser PrimitivePatPattern
ppPattern = PPInductivePat <$> lowerId <*> many ppAtom
<|> do ops <- gets patternOps
makeExprParser ppAtom (makeTable ops)
<?> "primitive pattern pattern"
where
makeTable :: [Op] -> [[Operator Parser PrimitivePatPattern]]
makeTable ops =
map (map toOperator) (groupBy (\x y -> priority x == priority y) ops)
toOperator :: Op -> Operator Parser PrimitivePatPattern
toOperator = infixToOperator inductive2
inductive2 op = (\x y -> PPInductivePat (repr op) [x, y]) <$ operator (repr op)
ppAtom :: Parser PrimitivePatPattern
ppAtom = PPWildCard <$ symbol "_"
<|> PPPatVar <$ symbol "$"
<|> PPValuePat <$> (string "#$" >> lowerId)
<|> PPInductivePat "nil" [] <$ (symbol "[" >> symbol "]")
<|> makeTupleOrParen ppPattern PPTuplePat
pdPattern :: Parser PrimitiveDataPattern
pdPattern = makeExprParser pdApplyOrAtom table
<?> "primitive data pattern"
where
table :: [[Operator Parser PrimitiveDataPattern]]
table =
[ [ InfixR (PDConsPat <$ symbol "::") ]
]
pdApplyOrAtom :: Parser PrimitiveDataPattern
pdApplyOrAtom = PDInductivePat <$> upperId <*> many pdAtom
<|> PDSnocPat <$> (symbol "snoc" >> pdAtom) <*> pdAtom
<|> pdAtom
pdAtom :: Parser PrimitiveDataPattern
pdAtom = PDWildCard <$ symbol "_"
<|> PDPatVar <$> patVarLiteral
<|> PDPatVar <$> ident
<|> PDConstantPat <$> constantExpr
<|> pdCollection
<|> makeTupleOrParen pdPattern PDTuplePat
where
pdCollection :: Parser PrimitiveDataPattern
pdCollection = do
elts <- brackets (sepBy pdPattern comma)
return (foldr PDConsPat PDEmptyPat elts)
--
-- Tokens
--
-- Space Comsumer
sc :: Parser ()
sc = L.space space1 lineCmnt blockCmnt
where
lineCmnt = L.skipLineComment "--"
blockCmnt = L.skipBlockCommentNested "{-" "-}"
lexeme :: Parser a -> Parser a
lexeme = L.lexeme sc
positiveIntegerLiteral :: Parser Integer
positiveIntegerLiteral = lexeme L.decimal
<?> "unsinged integer"
charLiteral :: Parser Char
charLiteral = between (char '\'') (symbol "\'") L.charLiteral
<?> "character"
stringLiteral :: Parser String
stringLiteral = char '\"' *> manyTill L.charLiteral (symbol "\"")
<?> "string"
boolLiteral :: Parser Bool
boolLiteral = reserved "True" $> True
<|> reserved "False" $> False
<?> "boolean"
positiveFloatLiteral :: Parser Double
positiveFloatLiteral = lexeme L.float
<?> "unsigned float"
varWithIndicesLiteral :: Parser VarWithIndices
varWithIndicesLiteral =
lexeme (VarWithIndices <$> ident' <*> many varIndex)
varWithIndicesLiteral' :: Parser VarWithIndices
varWithIndicesLiteral' =
lexeme (VarWithIndices <$> ident' <*> some varIndex)
varIndex :: Parser VarIndex
varIndex = (char '_' >> VSubscript <$> ident')
<|> (char '~' >> VSuperscript <$> ident')
<|> parens (VGroupScripts <$> some varIndex)
<|> braces (VSymmScripts <$> some varIndex)
<|> brackets (VAntiSymmScripts <$> some varIndex)
patVarLiteral :: Parser String
patVarLiteral = char '$' >> ident
-- Parse infix (binary operator) literal.
-- If the operator is prefixed with '!', |isWedge| is turned to true.
infixLiteral :: String -> Parser Op
infixLiteral sym =
try (do wedge <- optional (char '!')
opSym <- operator' sym
ops <- gets exprOps
let opInfo = findOpFrom opSym ops
return $ opInfo { isWedge = isJust wedge })
<?> "infix"
where
-- operator without try
operator' :: String -> Parser String
operator' sym = string sym <* notFollowedBy opChar <* sc
reserved :: String -> Parser ()
reserved w = (lexeme . try) (string w *> notFollowedBy identChar)
symbol :: String -> Parser ()
symbol sym = try (L.symbol sc sym) >> pure ()
operator :: String -> Parser String
operator sym = try $ string sym <* notFollowedBy opChar <* sc
-- |infixLiteral| for pattern infixes.
patInfixLiteral :: String -> Parser Op
patInfixLiteral sym =
try (do opSym <- string sym <* notFollowedBy patOpChar <* sc
ops <- gets patternOps
let opInfo = findOpFrom opSym ops
return opInfo)
-- Characters that can consist expression operators.
opChar :: Parser Char
opChar = oneOf ("%^&*-+\\|:<>?!./'#@$" ++ "∧")
-- Characters that can consist pattern operators.
-- ! ? # @ $ are omitted because they can appear at the beginning of atomPattern
patOpChar :: Parser Char
patOpChar = oneOf "%^&*-+\\|:<>./'"
newPatOp :: Parser String
newPatOp = (:) <$> patOpChar <*> many (patOpChar <|> oneOf "!?#@$")
-- Characters that consist identifiers.
-- Note that 'alphaNumChar' can also parse greek letters.
identChar :: Parser Char
identChar = alphaNumChar
<|> oneOf (['?', '\'', '/'] ++ mathSymbols)
identString :: Parser String
identString = do
strs <- many substr
return $ concat strs
where
substr = ((:) <$> try (char '.' <* notFollowedBy (char '.')) <*> many opChar)
<|> (:[]) <$> identChar
-- Non-alphabetical symbols that are allowed for identifiers
mathSymbols :: String
mathSymbols = "∂∇"
parens :: Parser a -> Parser a
parens = between (symbol "(") (symbol ")")
braces :: Parser a -> Parser a
braces = between (symbol "{") (symbol "}")
brackets :: Parser a -> Parser a
brackets = between (symbol "[") (symbol "]")
comma :: Parser ()
comma = symbol ","
-- Notes on identifiers:
-- * Identifiers must be able to include greek letters and some symbols in
-- |mathSymbols|.
-- * Only identifiers starting with capital English letters ('A' - 'Z') can be
-- parsed as |upperId|. Identifiers starting with capital Greek letters must
-- be regarded as |lowerId|.
lowerId :: Parser String
lowerId = (lexeme . try) (p >>= check)
where
p = (:) <$> satisfy checkHead <*> identString
checkHead c = c `elem` mathSymbols || isLetter c && not (isAsciiUpper c)
check x = if x `elem` lowerReservedWords
then fail $ "keyword " ++ show x ++ " cannot be an identifier"
else return x
upperId :: Parser String
upperId = (lexeme . try) (p >>= check)
where
p = (:) <$> satisfy isAsciiUpper <*> many alphaNumChar
check x = if x `elem` upperReservedWords
then fail $ "keyword " ++ show x ++ " cannot be an identifier"
else return x
-- union of lowerId and upperId
ident :: Parser String
ident = (lexeme . try) (p >>= check)
where
p = (:) <$> satisfy checkHead <*> identString
checkHead c = c `elem` mathSymbols || isLetter c
check x = if x `elem` (lowerReservedWords ++ upperReservedWords)
then fail $ "keyword " ++ show x ++ " cannot be an identifier"
else return x
-- |ident| not followed by a space
ident' :: Parser String
ident' = try (p >>= check)
where
p = (:) <$> satisfy checkHead <*> identString
checkHead c = c `elem` mathSymbols || isLetter c
check x = if x `elem` (lowerReservedWords ++ upperReservedWords)
then fail $ "keyword " ++ show x ++ " cannot be an identifier"
else return x
upperReservedWords :: [String]
upperReservedWords =
[ "True"
, "False"
]
lowerReservedWords :: [String]
lowerReservedWords =
[ "loadFile"
, "load"
, "def"
, "if"
, "then"
, "else"
, "seq"
, "capply"
, "memoizedLambda"
, "cambda"
, "let"
, "in"
, "where"
, "withSymbols"
, "loop"
, "forall"
, "match"
, "matchDFS"
, "matchAll"
, "matchAllDFS"
, "as"
, "with"
, "matcher"
, "do"
, "something"
, "undefined"
, "algebraicDataMatcher"
, "generateTensor"
, "tensor"
, "contract"
, "tensorMap"
, "tensorMap2"
, "transpose"
, "subrefs"
, "subrefs!"
, "suprefs"
, "suprefs!"
, "userRefs"
, "userRefs!"
, "function"
, "infixl"
, "infixr"
, "infix"
]
--
-- Utils
--
makeTupleOrParen :: Parser a -> ([a] -> a) -> Parser a
makeTupleOrParen parser tupleCtor = do
elems <- parens $ sepBy parser comma
case elems of
[elem] -> return elem
_ -> return $ tupleCtor elems
indentGuardEQ :: Pos -> Parser Pos
indentGuardEQ pos = L.indentGuard sc EQ pos
indentGuardGT :: Pos -> Parser Pos
indentGuardGT pos = L.indentGuard sc GT pos
-- Variant of 'some' that requires every element to be at the same indentation level
alignSome :: Parser a -> Parser [a]
alignSome p = do
pos <- L.indentLevel
some (indentGuardEQ pos >> p)
-- Useful for parsing syntax like function applications, where all 'arguments'
-- should be indented deeper than the 'function'.
indentBlock :: Parser a -> Parser b -> Parser (a, [b])
indentBlock phead parg = do
pos <- L.indentLevel
head <- phead
args <- many (indentGuardGT pos >> parg)
return (head, args)
indented :: Parser Pos
indented = indentGuardGT pos1
infixToOperator :: (Op -> Parser (a -> a -> a)) -> Op -> Operator Parser a
infixToOperator opToParser op =
case assoc op of
E.InfixL -> InfixL (opToParser op)
E.InfixR -> InfixR (opToParser op)
E.InfixN -> InfixN (opToParser op)
tupleOrSome :: Parser a -> Parser [a]
tupleOrSome p = parens (sepBy p comma) <|> some p