Files
gf-core/src/GF/Source/LexGF.x

135 lines
4.5 KiB
Haskell

-- -*- haskell -*-
-- This Alex file was machine-generated by the BNF converter
-- Lines with -- H have been hacked for greater performance
{
module LexGF where
import SharedString -- H
import ErrM
}
$l = [a-zA-Z\192 - \255] # [\215 \247] -- isolatin1 letter FIXME
$c = [A-Z\192-\221] # [\215] -- capital isolatin1 letter FIXME
$s = [a-z\222-\255] # [\247] -- small isolatin1 letter FIXME
$d = [0-9] -- digit
$i = [$l $d _ '] -- identifier character
$u = [\0-\255] -- universal: any character
@rsyms = -- reserved words consisting of special symbols
\; | \= | \{ | \} | \( | \) | \: | \- \> | \* \* | \, | \[ | \] | \. | \| | \? | \< | \> | \@ | \! | \* | \\ | \= \> | \+ \+ | \+ | \_ | \$ | \/ | \-
:-
"--" [.]* ; -- Toss single line comments
"{-" ([$u # \-] | \- [$u # \}])* ("-")+ "}" ;
$white+ ;
@rsyms { tok (\p s -> PT p (TS $ shareString s)) } -- H
\' ($u # \')* \' { tok (\p s -> PT p (eitherResIdent (T_LString . shareString) s)) } -- H
$l $i* { tok (\p s -> PT p (eitherResIdent (TV . shareString) s)) } -- H
\" ([$u # [\" \\ \n]] | (\\ (\" | \\ | \' | n | t)))* \"{ tok (\p s -> PT p (TL $ unescapeInitTail $ shareString s)) } -- H
$d+ { tok (\p s -> PT p (TI s)) }
{
tok f p s = f p s
data Tok =
TS !String -- reserved words -- H
| TL !String -- string literals -- H
| TI String -- integer literals
| TV !String -- identifiers -- H
| TD String -- double precision float literals
| TC String -- character literals
| T_LString !String -- H
deriving (Eq,Show,Ord)
data Token =
PT Posn Tok
| Err Posn
deriving (Eq,Show,Ord)
tokenPos (PT (Pn _ l _) _ :_) = "line " ++ show l
tokenPos (Err (Pn _ l _) :_) = "line " ++ show l
tokenPos _ = "end of file"
posLineCol (Pn _ l c) = (l,c)
mkPosToken t@(PT p _) = (posLineCol p, prToken t)
prToken t = case t of
PT _ (TS s) -> s
PT _ (TI s) -> s
PT _ (TV s) -> s
PT _ (TD s) -> s
PT _ (TC s) -> s
PT _ (T_LString s) -> s
_ -> show t
data BTree = N | B String Tok BTree BTree deriving (Show)
eitherResIdent :: (String -> Tok) -> String -> Tok
eitherResIdent tv s = treeFind resWords
where
treeFind N = tv s
treeFind (B a t left right) | s < a = treeFind left
| s > a = treeFind right
| s == a = t
resWords = b "lincat" (b "def" (b "Type" (b "Str" (b "PType" (b "Lin" N N) N) (b "Tok" (b "Strs" N N) N)) (b "cat" (b "case" (b "abstract" N N) N) (b "data" (b "concrete" N N) N))) (b "include" (b "fun" (b "fn" (b "flags" N N) N) (b "in" (b "grammar" N N) N)) (b "interface" (b "instance" (b "incomplete" N N) N) (b "lin" (b "let" N N) N)))) (b "resource" (b "out" (b "of" (b "lintype" (b "lindef" N N) N) (b "oper" (b "open" N N) N)) (b "pattern" (b "param" (b "package" N N) N) (b "printname" (b "pre" N N) N))) (b "union" (b "table" (b "strs" (b "reuse" N N) N) (b "transfer" (b "tokenizer" N N) N)) (b "where" (b "variants" (b "var" N N) N) (b "with" N N))))
where b s = B s (TS s)
unescapeInitTail :: String -> String
unescapeInitTail = unesc . tail where
unesc s = case s of
'\\':c:cs | elem c ['\"', '\\', '\''] -> c : unesc cs
'\\':'n':cs -> '\n' : unesc cs
'\\':'t':cs -> '\t' : unesc cs
'"':[] -> []
c:cs -> c : unesc cs
_ -> []
-------------------------------------------------------------------
-- Alex wrapper code.
-- A modified "posn" wrapper.
-------------------------------------------------------------------
data Posn = Pn !Int !Int !Int
deriving (Eq, Show,Ord)
alexStartPos :: Posn
alexStartPos = Pn 0 1 1
alexMove :: Posn -> Char -> Posn
alexMove (Pn a l c) '\t' = Pn (a+1) l (((c+7) `div` 8)*8+1)
alexMove (Pn a l c) '\n' = Pn (a+1) (l+1) 1
alexMove (Pn a l c) _ = Pn (a+1) l (c+1)
type AlexInput = (Posn, -- current position,
Char, -- previous char
String) -- current input string
tokens :: String -> [Token]
tokens str = go (alexStartPos, '\n', str)
where
go :: (Posn, Char, String) -> [Token]
go inp@(pos, _, str) =
case alexScan inp 0 of
AlexEOF -> []
AlexError (pos, _, _) -> fail $ show pos ++ ": lexical error"
AlexSkip inp' len -> go inp'
AlexToken inp' len act -> act pos (take len str) : (go inp')
alexGetChar :: AlexInput -> Maybe (Char,AlexInput)
alexGetChar (p, c, []) = Nothing
alexGetChar (p, _, (c:s)) =
let p' = alexMove p c
in p' `seq` Just (c, (p', c, s))
alexInputPrevChar :: AlexInput -> Char
alexInputPrevChar (p, c, s) = c
}