hopefully compiles properly

[proglang.git] / Lexsyntax.x

diff --git a/Lexsyntax.x b/Lexsyntax.x
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+-- -*- haskell -*-
+-- This Alex file was machine-generated by the BNF converter
+{
+module Lexsyntax where
+
+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 =    -- symbols and non-identifier-like reserved words
+   \= | \; | \{ | \} | \( | \) | \+ \+ | \- \- | \- | \< | \< \= | \> | \> \= | \= \= | \! \= | \+ | \* | \/
+
+:-
+"//" [.]* ; -- Toss single line comments
+"/*" ([$u # \*] | \* [$u # \/])* ("*")+ "/" ; 
+
+$white+ ;
+@rsyms { tok (\p s -> PT p (TS $ share s)) }
+
+$l $i*   { tok (\p s -> PT p (eitherResIdent (TV . share) s)) }
+
+
+$d+      { tok (\p s -> PT p (TI $ share s))    }
+
+
+{
+
+tok f p s = f p s
+
+share :: String -> String
+share = id
+
+data Tok =
+   TS !String     -- reserved words and symbols
+ | TL !String     -- string literals
+ | TI !String     -- integer literals
+ | TV !String     -- identifiers
+ | TD !String     -- double precision float literals
+ | TC !String     -- character literals
+
+ 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
+
+  _ -> 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 "print" (b "false" (b "else" (b "bool" N N) N) (b "int" (b "if" N N) N)) (b "true" (b "readInt" (b "readBool" N N) N) (b "while" 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
+}