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|
{-|
Module : VeriFuzz.Parser
Description : Minimal Verilog parser to reconstruct the AST.
Copyright : (c) 2019, Yann Herklotz Grave
License : GPL-3
Maintainer : ymherklotz [at] gmail [dot] com
Stability : experimental
Portability : POSIX
Minimal Verilog parser to reconstruct the AST. This parser does not support the
whole Verilog syntax, as the AST does not support it either.
-}
module VeriFuzz.Parser
( -- * Parsers
parseVerilog
, parseVerilogSrc
, parseDescription
, parseModDecl
, parseContAssign
, parseExpr
)
where
import Data.Functor (($>))
import Data.Functor.Identity (Identity)
import qualified Data.Text as T
import Text.Parsec
import Text.Parsec.Expr
import VeriFuzz.AST
--import VeriFuzz.CodeGen
import VeriFuzz.Internal
import VeriFuzz.Lexer
type Parser = Parsec String ()
type ParseOperator = Operator String () Identity
sBinOp :: BinaryOperator -> Expr -> Expr -> Expr
sBinOp = sOp BinOp where sOp f b a = f a b
parseExpr' :: Parser Expr
parseExpr' = buildExpressionParser parseTable parseTerm <?> "expr"
matchHex :: Char -> Bool
matchHex c = c == 'h' || c == 'H'
--matchBin :: Char -> Bool
--matchBin c = c == 'b' || c == 'B'
matchDec :: Char -> Bool
matchDec c = c == 'd' || c == 'D'
matchOct :: Char -> Bool
matchOct c = c == 'o' || c == 'O'
-- | Parse a Number depending on if it is in a hex or decimal form. Octal and
-- binary are not supported yet.
parseNum :: Parser Expr
parseNum = do
size <- fromIntegral <$> decimal
_ <- string "'"
matchNum size
where
matchNum size =
(satisfy matchHex >> Number size <$> hexadecimal)
<|> (satisfy matchDec >> Number size <$> decimal)
<|> (satisfy matchOct >> Number size <$> octal)
parseVar :: Parser Expr
parseVar = Id <$> ident
parseFunction :: Parser Function
parseFunction =
reserved "unsigned" $> UnSignedFunc <|> reserved "signed" $> SignedFunc
parseFun :: Parser Expr
parseFun = do
f <- spaces *> reservedOp "$" *> parseFunction
expr <- string "(" *> spaces *> parseExpr
_ <- spaces *> string ")" *> spaces
return $ Func f expr
parseTerm :: Parser Expr
parseTerm =
parens parseExpr
<|> (Concat <$> aroundList (string "{") (string "}") parseExpr)
<|> parseFun
<|> lexeme parseNum
<|> parseVar
<?> "simple expr"
-- | Parses the ternary conditional operator. It will behave in a right
-- associative way.
parseCond :: Expr -> Parser Expr
parseCond e = do
_ <- spaces *> reservedOp "?"
expr <- spaces *> parseExpr
_ <- spaces *> reservedOp ":"
Cond e expr <$> parseExpr
parseExpr :: Parser Expr
parseExpr = do
e <- parseExpr'
option e . try $ parseCond e
-- | Table of binary and unary operators that encode the right precedence for
-- each.
parseTable :: [[ParseOperator Expr]]
parseTable
= [ [prefix "!" (UnOp UnLNot), prefix "~" (UnOp UnNot)]
, [ prefix "&" (UnOp UnAnd)
, prefix "|" (UnOp UnOr)
, prefix "~&" (UnOp UnNand)
, prefix "~|" (UnOp UnNor)
, prefix "^" (UnOp UnXor)
, prefix "~^" (UnOp UnNxor)
, prefix "^~" (UnOp UnNxorInv)
]
, [prefix "+" (UnOp UnPlus), prefix "-" (UnOp UnMinus)]
, [binary "**" (sBinOp BinPower) AssocRight]
, [ binary "*" (sBinOp BinTimes) AssocLeft
, binary "/" (sBinOp BinDiv) AssocLeft
, binary "%" (sBinOp BinMod) AssocLeft
]
, [ binary "+" (sBinOp BinPlus) AssocLeft
, binary "-" (sBinOp BinPlus) AssocLeft
]
, [ binary "<<" (sBinOp BinLSL) AssocLeft
, binary ">>" (sBinOp BinLSR) AssocLeft
]
, [ binary "<<<" (sBinOp BinASL) AssocLeft
, binary ">>>" (sBinOp BinASR) AssocLeft
]
, [ binary "<" (sBinOp BinLT) AssocNone
, binary ">" (sBinOp BinGT) AssocNone
, binary "<=" (sBinOp BinLEq) AssocNone
, binary ">=" (sBinOp BinLEq) AssocNone
]
, [ binary "==" (sBinOp BinEq) AssocNone
, binary "!=" (sBinOp BinNEq) AssocNone
]
, [ binary "===" (sBinOp BinEq) AssocNone
, binary "!==" (sBinOp BinNEq) AssocNone
]
, [binary "&" (sBinOp BinAnd) AssocLeft]
, [ binary "^" (sBinOp BinXor) AssocLeft
, binary "^~" (sBinOp BinXNor) AssocLeft
, binary "~^" (sBinOp BinXNorInv) AssocLeft
]
, [binary "|" (sBinOp BinOr) AssocLeft]
, [binary "&&" (sBinOp BinLAnd) AssocLeft]
, [binary "||" (sBinOp BinLOr) AssocLeft]
]
binary :: String -> (a -> a -> a) -> Assoc -> ParseOperator a
binary name fun = Infix ((reservedOp name <?> "binary") >> return fun)
prefix :: String -> (a -> a) -> ParseOperator a
prefix name fun = Prefix ((reservedOp name <?> "prefix") >> return fun)
aroundList :: Parser a -> Parser b -> Parser c -> Parser [c]
aroundList a b c = lexeme $ do
l <- a *> spaces *> commaSep c
_ <- b
return l
parseContAssign :: Parser ContAssign
parseContAssign = do
var <- reserved "assign" *> ident
expr <- reservedOp "=" *> parseExpr
_ <- symbol ";"
return $ ContAssign var expr
-- | Parse a range and return the total size. As it is inclusive, 1 has to be
-- added to the difference.
parseRange :: Parser Int
parseRange = do
rangeH <- symbol "[" *> decimal
rangeL <- symbol ":" *> decimal
_ <- symbol "]"
return . fromIntegral $ rangeH - rangeL + 1
ident :: Parser Identifier
ident = Identifier . T.pack <$> identifier
parseNetDecl :: Maybe PortDir -> Parser ModItem
parseNetDecl pd = do
t <- option Wire type_
sign <- option False (reserved "signed" $> True)
range <- option 1 parseRange
name <- ident
_ <- symbol ";"
return . Decl pd . Port t sign range $ name
where type_ = reserved "wire" $> Wire <|> reserved "reg" $> Reg
parsePortDir :: Parser PortDir
parsePortDir =
reserved "output"
$> PortOut
<|> reserved "input"
$> PortIn
<|> reserved "inout"
$> PortInOut
parseDecl :: Parser ModItem
parseDecl = (Just <$> parsePortDir >>= parseNetDecl) <|> parseNetDecl Nothing
parseModItem :: Parser ModItem
parseModItem = (ModCA <$> parseContAssign) <|> parseDecl
parseModList :: Parser [Identifier]
parseModList = list <|> spaces $> []
where list = aroundList (string "(") (string ")") ident
parseModDecl :: Parser ModDecl
parseModDecl = do
name <- reserved "module" *> ident
modL <- fmap defaultPort <$> parseModList
_ <- symbol ";"
modItem <- lexeme $ option [] . try $ many1 parseModItem
_ <- reserved "endmodule"
return $ ModDecl name [] modL modItem
parseDescription :: Parser Description
parseDescription = Description <$> lexeme parseModDecl
parseVerilogSrc :: Parser VerilogSrc
parseVerilogSrc = VerilogSrc <$> (whiteSpace *> many parseDescription)
parseVerilog :: String -> String -> Either ParseError VerilogSrc
parseVerilog = parse parseVerilogSrc
|