crayne parser: step and p

author: Joe Crayne <joe@jerkface.net> 2019-06-13 16:02:54 -0400
committer: Joe Crayne <joe@jerkface.net> 2019-06-13 16:02:54 -0400
commit: 76e4b1bd5310f65608521967db653570bb73ecbe (patch)
tree: 48b85b2400e98cda9a67e73e5cb94a3291a305df
parent: 3e342655168472ead7e6fd38ef4a21d6132401af (diff)
1 files changed, 99 insertions, 82 deletions
diff --git a/src/Wavefront.hs b/src/Wavefront.hs
index 5cef6dc..74d0b39 100644
--- a/src/Wavefront.hs
+++ b/src/Wavefront.hs
@@ -40,40 +40,44 @@ data ObjBuilder m = ObjBuilder
    , mtllib           :: [S.ByteString] -> m ()
    , objectName       :: S.ByteString -> m ()
    , bmat             :: ParamSpec -> [Double] -> m ()
+    , step             :: [Int] -> m ()
+    , points           :: [Int] -> m ()
    , badToken         :: L.ByteString -> m ()
    }
 nullBuilder :: Applicative m => ObjBuilder m
 nullBuilder = ObjBuilder
-    { vertex           = \vs -> pure ()
+    { vertex           = \vs             -> pure ()
-    , vertexT          = \vs -> pure ()
+    , vertexT          = \vs             -> pure ()
-    , vertexN          = \vs -> pure ()
+    , vertexN          = \vs             -> pure ()
-    , vertexP          = \vs -> pure ()
+    , vertexP          = \vs             -> pure ()
-    , face             = \is -> pure ()
+    , face             = \is             -> pure ()
-    , cstype           = \isRat typ -> pure ()
+    , cstype           = \isRat typ      -> pure ()
-    , curv2            = \is -> pure ()
+    , curv2            = \is             -> pure ()
-    , curv             = \u0 v0 is -> pure ()
+    , curv             = \u0 v0 is       -> pure ()
-    , parm             = \uv is -> pure ()
+    , parm             = \uv is          -> pure ()
-    , specialPoints    = \is -> pure ()
+    , specialPoints    = \is             -> pure ()
-    , endFreeForm      = pure ()
+    , endFreeForm      =                    pure ()
-    , ctech            = \approx -> pure ()
+    , ctech            = \approx         -> pure ()
-    , stech            = \approx -> pure ()
+    , stech            = \approx         -> pure ()
-    , deg              = \is -> pure ()
+    , deg              = \is             -> pure ()
    , surf             = \u0 u1 v0 v1 ts -> pure ()
-    , trim             = \ss -> pure ()
+    , trim             = \ss             -> pure ()
-    , hole             = \ss -> pure ()
+    , hole             = \ss             -> pure ()
-    , specialCurves    = \ss -> pure ()
+    , specialCurves    = \ss             -> pure ()
-    , equivalentCurves = \ccs -> pure ()
+    , equivalentCurves = \ccs            -> pure ()
-    , groups           = \gs -> pure ()
+    , groups           = \gs             -> pure ()
-    , smoothingGroup   = \sg -> pure ()
+    , smoothingGroup   = \sg             -> pure ()
-    , mergingGroup     = \mg δ -> pure ()
+    , mergingGroup     = \mg δ           -> pure ()
-    , usemtl           = \mtl -> pure ()
+    , usemtl           = \mtl            -> pure ()
-    , deprecated_cdc   = \is -> pure ()
+    , deprecated_cdc   = \is             -> pure ()
-    , deprecated_bzp   = \is -> pure ()
+    , deprecated_bzp   = \is             -> pure ()
-    , mtllib           = \fns -> pure ()
+    , mtllib           = \fns            -> pure ()
-    , objectName       = \obn -> pure ()
+    , objectName       = \obn            -> pure ()
-    , bmat             = \uv fs -> pure ()
+    , bmat             = \uv fs          -> pure ()
-    , badToken         = \bs -> pure ()
+    , step             = \is             -> pure ()
+    , points           = \is             -> pure ()
+    , badToken         = \bs             -> pure ()
    }
@@ -168,22 +172,23 @@ findToken (ObjConfig args) bs = case L.dropWhile (\c -> isSpace c || c=='\\') bs
    21      mg
    22      mtllib
    23      o
-    24      parm
+    24      p
-    25      s
+    25      parm
-    26      scrv
+    26      s
-    27  x   shadow_obj
+    27      scrv
-    28      sp
+    28  x   shadow_obj
-    29      stech -- for all except these,
+    29      sp
-    30  x   step  -- Two chars suffice to distinguish
+    30      stech -- for all except these,
-    31      surf
+    31      step  -- Two chars suffice to distinguish
-    32  x   trace_obj -- for all except these,
+    32      surf
-    33      trim      -- Two chars suffice to distinguish
+    33  x   trace_obj -- for all except these,
-    34  x   usemap -- for all except these,
+    34      trim      -- Two chars suffice to distinguish
-    35      usemtl -- Two chars suffice to distinguish
+    35  x   usemap -- for all except these,
-    36      v
+    36      usemtl -- Two chars suffice to distinguish
-    37      vn
+    37      v
-    38      vp
+    38      vn
-    39      vt
+    39      vp
+    40      vt
 -}
@@ -322,7 +327,8 @@ parseOBJ builder args bs0
                (objn,bs') -> do
                    objectName builder (L.toStrict objn)
                    parseOBJ builder args bs'
-        _   -> badToken builder bs
+        'p' -> parseI points 2
+        _   -> bad bs
    | otherwise = case L.take 2 bs of
        "vt" -> parseV vertexT 3
        "vn" -> parseV vertexN 3
@@ -340,14 +346,14 @@ parseOBJ builder args bs0
                    parseOBJ builder args bs'
        "cs" -> -- cstype
                let parseRat = parseChar 'r'
-                    parseTyp tok cont | lengthLessThan 3 tok = badToken builder tok
+                    parseTyp tok cont | lengthLessThan 3 tok = bad tok
                                      | otherwise = case L.index tok 2 of
                        'a' -> cont Bmatrix  $ next 3 tok
                        'z' -> cont Bezier   $ next 3 tok
                        'p' -> cont Bspline  $ next 3 tok
                        'r' -> cont Cardinal $ next 3 tok
                        'y' -> cont Taylor   $ next 3 tok
-                        _   -> badToken builder tok
+                        _   -> bad tok
                in parseRat (next 2 bs) $ \isRat bs' -> do
                    parseTyp bs' $ \typ bs'' -> do
                        cstype builder isRat typ
@@ -355,7 +361,7 @@ parseOBJ builder args bs0
        "ct" -> -- ctech
                let tok = next 2 bs
                in if lengthLessThan 2 tok
-                    then badToken builder tok
+                    then bad tok
                    else case L.index tok 1 of
                        'p' -> -- cparm
                               parseFloats (findToken args) (next 2 tok) $ \is bs' -> do
@@ -372,9 +378,9 @@ parseOBJ builder args bs0
                                    let δ:θ:_ = fs ++ repeat 1.0
                                    ctech builder (CurvatureBasedPolygon δ θ)
                                    parseOBJ builder args bs'
-                        _   -> badToken builder tok
+                        _   -> bad tok
        "cu" -> if lengthLessThan 5 bs
-                    then badToken builder bs
+                    then bad bs
                    else if L.index bs 4 == '2'
                            then parseI curv2 5 -- curv2
                            else do -- curv
@@ -404,36 +410,44 @@ parseOBJ builder args bs0
                    specialCurves builder ss
                    parseOBJ builder args bs'
        "sp" -> parseI specialPoints 3
-        "st" -> -- stech
+        "st" -> -- stech or step
-                let tok = next 2 bs
+                if lengthLessThan 4 bs then bad bs
-                in if lengthLessThan 2 tok
+                else case L.index bs 3 of
-                    then badToken builder tok
+                  'c' ->
-                    else case L.index tok 1 of
+                    -- stech
-                        'p' -> -- cparma/cparmb
+                    let tok = next 2 bs
-                               if lengthLessThan 6 tok
+                    in if lengthLessThan 2 tok
-                                then badToken builder tok
+                        then bad tok
-                                else if L.index tok 5 == 'b'
+                        else case L.index tok 1 of
-                                        then -- cparmb
+                            'p' -> -- cparma/cparmb
-                                           parseFloats (findToken args) (next 5 tok) $ \is bs' -> do
+                                   if lengthLessThan 6 tok
-                                                let x:_ = is ++ [0]
+                                    then bad tok
-                                                stech builder (UniformAfterTrimming x)
+                                    else if L.index tok 5 == 'b'
-                                                parseOBJ builder args bs'
+                                            then -- cparmb
-                                        else -- cparma
+                                               parseFloats (findToken args) (next 5 tok) $ \is bs' -> do
-                                           parseFloats (findToken args) (next 5 tok) $ \is bs' -> do
+                                                    let x:_ = is ++ [0]
-                                                let x:y:_ = is ++ [0]
+                                                    stech builder (UniformAfterTrimming x)
-                                                stech builder (UniformIsoparametric x y)
+                                                    parseOBJ builder args bs'
-                                                parseOBJ builder args bs'
+                                            else -- cparma
-                        's' -> -- cspace
+                                               parseFloats (findToken args) (next 5 tok) $ \is bs' -> do
-                               parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do
+                                                    let x:y:_ = is ++ [0]
-                                    let x:_ = fs ++ [1.0]
+                                                    stech builder (UniformIsoparametric x y)
-                                    stech builder (MaxLengthPolytopal x)
+                                                    parseOBJ builder args bs'
-                                    parseOBJ builder args bs'
+                            's' -> -- cspace
-                        'u' -> -- curv
+                                   parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do
-                               parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do
+                                        let x:_ = fs ++ [1.0]
-                                    let δ:θ:_ = fs ++ repeat 1.0
+                                        stech builder (MaxLengthPolytopal x)
-                                    stech builder (CurvatureBasedPolytope δ θ)
+                                        parseOBJ builder args bs'
-                                    parseOBJ builder args bs'
+                            'u' -> -- curv
-                        _   -> badToken builder tok
+                                   parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do
+                                        let δ:θ:_ = fs ++ repeat 1.0
+                                        stech builder (CurvatureBasedPolytope δ θ)
+                                        parseOBJ builder args bs'
+                            _   -> bad tok
+                  _   -> -- step
+                         parseI step 4
        "su" -> -- surf
                parseFloatsN 4 (findToken args) (next 2 bs) $ \fs bs' -> do
                    parseTriples (findToken args) bs' $ \ts bs'' -> do
@@ -463,10 +477,13 @@ parseOBJ builder args bs0
                                                        in (fn <> L.take 1 ext <> f) : fs
                        mtllib builder (map L.toStrict $ slurp fnn)
                        parseOBJ builder args bs'
-        -- TODO: call,csh,step,c_interp,d_interp,lod,shadow_obj,trace_obj,bevel
+        -- TODO: call,csh,c_interp,d_interp,lod,shadow_obj,trace_obj,bevel
-        _    -> badToken builder bs
+        _    -> bad bs
    where
        bs = findToken args bs0
+        bad bs = case L.break (=='\n') bs of
+            (x,bs') -> do badToken builder x
+                          parseOBJ builder args bs'
        next n xs = nextToken (findToken args) $ L.drop n xs
        parseChar c tok cont = case L.uncons tok of
                        Just (x,cs) | x==c -> cont True $ next 0 cs
author	Joe Crayne <joe@jerkface.net>	2019-06-13 16:02:54 -0400
committer	Joe Crayne <joe@jerkface.net>	2019-06-13 16:02:54 -0400
commit	76e4b1bd5310f65608521967db653570bb73ecbe (patch)
tree	48b85b2400e98cda9a67e73e5cb94a3291a305df
parent	3e342655168472ead7e6fd38ef4a21d6132401af (diff)

diff --git a/src/Wavefront.hs b/src/Wavefront.hs index 5cef6dc..74d0b39 100644 --- a/src/Wavefront.hs +++ b/src/Wavefront.hs
@@ -40,40 +40,44 @@ data ObjBuilder m = ObjBuilder
40	, mtllib :: [S.ByteString] -> m ()	40	, mtllib :: [S.ByteString] -> m ()
41	, objectName :: S.ByteString -> m ()	41	, objectName :: S.ByteString -> m ()
42	, bmat :: ParamSpec -> [Double] -> m ()	42	, bmat :: ParamSpec -> [Double] -> m ()
		43	, step :: [Int] -> m ()
		44	, points :: [Int] -> m ()
43	, badToken :: L.ByteString -> m ()	45	, badToken :: L.ByteString -> m ()
44	}	46	}
45		47
46	nullBuilder :: Applicative m => ObjBuilder m	48	nullBuilder :: Applicative m => ObjBuilder m
47	nullBuilder = ObjBuilder	49	nullBuilder = ObjBuilder
48	{ vertex = \vs -> pure ()	50	{ vertex = \vs -> pure ()
49	, vertexT = \vs -> pure ()	51	, vertexT = \vs -> pure ()
50	, vertexN = \vs -> pure ()	52	, vertexN = \vs -> pure ()
51	, vertexP = \vs -> pure ()	53	, vertexP = \vs -> pure ()
52	, face = \is -> pure ()	54	, face = \is -> pure ()
53	, cstype = \isRat typ -> pure ()	55	, cstype = \isRat typ -> pure ()
54	, curv2 = \is -> pure ()	56	, curv2 = \is -> pure ()
55	, curv = \u0 v0 is -> pure ()	57	, curv = \u0 v0 is -> pure ()
56	, parm = \uv is -> pure ()	58	, parm = \uv is -> pure ()
57	, specialPoints = \is -> pure ()	59	, specialPoints = \is -> pure ()
58	, endFreeForm = pure ()	60	, endFreeForm = pure ()
59	, ctech = \approx -> pure ()	61	, ctech = \approx -> pure ()
60	, stech = \approx -> pure ()	62	, stech = \approx -> pure ()
61	, deg = \is -> pure ()	63	, deg = \is -> pure ()
62	, surf = \u0 u1 v0 v1 ts -> pure ()	64	, surf = \u0 u1 v0 v1 ts -> pure ()
63	, trim = \ss -> pure ()	65	, trim = \ss -> pure ()
64	, hole = \ss -> pure ()	66	, hole = \ss -> pure ()
65	, specialCurves = \ss -> pure ()	67	, specialCurves = \ss -> pure ()
66	, equivalentCurves = \ccs -> pure ()	68	, equivalentCurves = \ccs -> pure ()
67	, groups = \gs -> pure ()	69	, groups = \gs -> pure ()
68	, smoothingGroup = \sg -> pure ()	70	, smoothingGroup = \sg -> pure ()
69	, mergingGroup = \mg δ -> pure ()	71	, mergingGroup = \mg δ -> pure ()
70	, usemtl = \mtl -> pure ()	72	, usemtl = \mtl -> pure ()
71	, deprecated_cdc = \is -> pure ()	73	, deprecated_cdc = \is -> pure ()
72	, deprecated_bzp = \is -> pure ()	74	, deprecated_bzp = \is -> pure ()
73	, mtllib = \fns -> pure ()	75	, mtllib = \fns -> pure ()
74	, objectName = \obn -> pure ()	76	, objectName = \obn -> pure ()
75	, bmat = \uv fs -> pure ()	77	, bmat = \uv fs -> pure ()
76	, badToken = \bs -> pure ()	78	, step = \is -> pure ()
		79	, points = \is -> pure ()
		80	, badToken = \bs -> pure ()
77	}	81	}
78		82
79		83
@@ -168,22 +172,23 @@ findToken (ObjConfig args) bs = case L.dropWhile (\c -> isSpace c \|\| c=='\\') bs
168	21 mg	172	21 mg
169	22 mtllib	173	22 mtllib
170	23 o	174	23 o
171	24 parm	175	24 p
172	25 s	176	25 parm
173	26 scrv	177	26 s
174	27 x shadow_obj	178	27 scrv
175	28 sp	179	28 x shadow_obj
176	29 stech -- for all except these,	180	29 sp
177	30 x step -- Two chars suffice to distinguish	181	30 stech -- for all except these,
178	31 surf	182	31 step -- Two chars suffice to distinguish
179	32 x trace_obj -- for all except these,	183	32 surf
180	33 trim -- Two chars suffice to distinguish	184	33 x trace_obj -- for all except these,
181	34 x usemap -- for all except these,	185	34 trim -- Two chars suffice to distinguish
182	35 usemtl -- Two chars suffice to distinguish	186	35 x usemap -- for all except these,
183	36 v	187	36 usemtl -- Two chars suffice to distinguish
184	37 vn	188	37 v
185	38 vp	189	38 vn
186	39 vt	190	39 vp
		191	40 vt
187		192
188	-}	193	-}
189		194
@@ -322,7 +327,8 @@ parseOBJ builder args bs0
322	(objn,bs') -> do	327	(objn,bs') -> do
323	objectName builder (L.toStrict objn)	328	objectName builder (L.toStrict objn)
324	parseOBJ builder args bs'	329	parseOBJ builder args bs'
325	_ -> badToken builder bs	330	'p' -> parseI points 2
		331	_ -> bad bs
326	\| otherwise = case L.take 2 bs of	332	\| otherwise = case L.take 2 bs of
327	"vt" -> parseV vertexT 3	333	"vt" -> parseV vertexT 3
328	"vn" -> parseV vertexN 3	334	"vn" -> parseV vertexN 3
@@ -340,14 +346,14 @@ parseOBJ builder args bs0
340	parseOBJ builder args bs'	346	parseOBJ builder args bs'
341	"cs" -> -- cstype	347	"cs" -> -- cstype
342	let parseRat = parseChar 'r'	348	let parseRat = parseChar 'r'
343	parseTyp tok cont \| lengthLessThan 3 tok = badToken builder tok	349	parseTyp tok cont \| lengthLessThan 3 tok = bad tok
344	\| otherwise = case L.index tok 2 of	350	\| otherwise = case L.index tok 2 of
345	'a' -> cont Bmatrix $ next 3 tok	351	'a' -> cont Bmatrix $ next 3 tok
346	'z' -> cont Bezier $ next 3 tok	352	'z' -> cont Bezier $ next 3 tok
347	'p' -> cont Bspline $ next 3 tok	353	'p' -> cont Bspline $ next 3 tok
348	'r' -> cont Cardinal $ next 3 tok	354	'r' -> cont Cardinal $ next 3 tok
349	'y' -> cont Taylor $ next 3 tok	355	'y' -> cont Taylor $ next 3 tok
350	_ -> badToken builder tok	356	_ -> bad tok
351	in parseRat (next 2 bs) $ \isRat bs' -> do	357	in parseRat (next 2 bs) $ \isRat bs' -> do
352	parseTyp bs' $ \typ bs'' -> do	358	parseTyp bs' $ \typ bs'' -> do
353	cstype builder isRat typ	359	cstype builder isRat typ
@@ -355,7 +361,7 @@ parseOBJ builder args bs0
355	"ct" -> -- ctech	361	"ct" -> -- ctech
356	let tok = next 2 bs	362	let tok = next 2 bs
357	in if lengthLessThan 2 tok	363	in if lengthLessThan 2 tok
358	then badToken builder tok	364	then bad tok
359	else case L.index tok 1 of	365	else case L.index tok 1 of
360	'p' -> -- cparm	366	'p' -> -- cparm
361	parseFloats (findToken args) (next 2 tok) $ \is bs' -> do	367	parseFloats (findToken args) (next 2 tok) $ \is bs' -> do
@@ -372,9 +378,9 @@ parseOBJ builder args bs0
372	let δ:θ:_ = fs ++ repeat 1.0	378	let δ:θ:_ = fs ++ repeat 1.0
373	ctech builder (CurvatureBasedPolygon δ θ)	379	ctech builder (CurvatureBasedPolygon δ θ)
374	parseOBJ builder args bs'	380	parseOBJ builder args bs'
375	_ -> badToken builder tok	381	_ -> bad tok
376	"cu" -> if lengthLessThan 5 bs	382	"cu" -> if lengthLessThan 5 bs
377	then badToken builder bs	383	then bad bs
378	else if L.index bs 4 == '2'	384	else if L.index bs 4 == '2'
379	then parseI curv2 5 -- curv2	385	then parseI curv2 5 -- curv2
380	else do -- curv	386	else do -- curv
@@ -404,36 +410,44 @@ parseOBJ builder args bs0
404	specialCurves builder ss	410	specialCurves builder ss
405	parseOBJ builder args bs'	411	parseOBJ builder args bs'
406	"sp" -> parseI specialPoints 3	412	"sp" -> parseI specialPoints 3
407	"st" -> -- stech	413	"st" -> -- stech or step
408	let tok = next 2 bs	414	if lengthLessThan 4 bs then bad bs
409	in if lengthLessThan 2 tok	415	else case L.index bs 3 of
410	then badToken builder tok	416	'c' ->
411	else case L.index tok 1 of	417	-- stech
412	'p' -> -- cparma/cparmb	418	let tok = next 2 bs
413	if lengthLessThan 6 tok	419	in if lengthLessThan 2 tok
414	then badToken builder tok	420	then bad tok
415	else if L.index tok 5 == 'b'	421	else case L.index tok 1 of
416	then -- cparmb	422	'p' -> -- cparma/cparmb
417	parseFloats (findToken args) (next 5 tok) $ \is bs' -> do	423	if lengthLessThan 6 tok
418	let x:_ = is ++ [0]	424	then bad tok
419	stech builder (UniformAfterTrimming x)	425	else if L.index tok 5 == 'b'
420	parseOBJ builder args bs'	426	then -- cparmb
421	else -- cparma	427	parseFloats (findToken args) (next 5 tok) $ \is bs' -> do
422	parseFloats (findToken args) (next 5 tok) $ \is bs' -> do	428	let x:_ = is ++ [0]
423	let x:y:_ = is ++ [0]	429	stech builder (UniformAfterTrimming x)
424	stech builder (UniformIsoparametric x y)	430	parseOBJ builder args bs'
425	parseOBJ builder args bs'	431	else -- cparma
426	's' -> -- cspace	432	parseFloats (findToken args) (next 5 tok) $ \is bs' -> do
427	parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do	433	let x:y:_ = is ++ [0]
428	let x:_ = fs ++ [1.0]	434	stech builder (UniformIsoparametric x y)
429	stech builder (MaxLengthPolytopal x)	435	parseOBJ builder args bs'
430	parseOBJ builder args bs'	436	's' -> -- cspace
431	'u' -> -- curv	437	parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do
432	parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do	438	let x:_ = fs ++ [1.0]
433	let δ:θ:_ = fs ++ repeat 1.0	439	stech builder (MaxLengthPolytopal x)
434	stech builder (CurvatureBasedPolytope δ θ)	440	parseOBJ builder args bs'
435	parseOBJ builder args bs'	441	'u' -> -- curv
436	_ -> badToken builder tok	442	parseFloats (findToken args) (next 2 tok) $ \fs bs' -> do
		443	let δ:θ:_ = fs ++ repeat 1.0
		444	stech builder (CurvatureBasedPolytope δ θ)
		445	parseOBJ builder args bs'
		446	_ -> bad tok
		447
		448	_ -> -- step
		449	parseI step 4
		450
437	"su" -> -- surf	451	"su" -> -- surf
438	parseFloatsN 4 (findToken args) (next 2 bs) $ \fs bs' -> do	452	parseFloatsN 4 (findToken args) (next 2 bs) $ \fs bs' -> do
439	parseTriples (findToken args) bs' $ \ts bs'' -> do	453	parseTriples (findToken args) bs' $ \ts bs'' -> do
@@ -463,10 +477,13 @@ parseOBJ builder args bs0
463	in (fn <> L.take 1 ext <> f) : fs	477	in (fn <> L.take 1 ext <> f) : fs
464	mtllib builder (map L.toStrict $ slurp fnn)	478	mtllib builder (map L.toStrict $ slurp fnn)
465	parseOBJ builder args bs'	479	parseOBJ builder args bs'
466	-- TODO: call,csh,step,c_interp,d_interp,lod,shadow_obj,trace_obj,bevel	480	-- TODO: call,csh,c_interp,d_interp,lod,shadow_obj,trace_obj,bevel
467	_ -> badToken builder bs	481	_ -> bad bs
468	where	482	where
469	bs = findToken args bs0	483	bs = findToken args bs0
		484	bad bs = case L.break (=='\n') bs of
		485	(x,bs') -> do badToken builder x
		486	parseOBJ builder args bs'
470	next n xs = nextToken (findToken args) $ L.drop n xs	487	next n xs = nextToken (findToken args) $ L.drop n xs
471	parseChar c tok cont = case L.uncons tok of	488	parseChar c tok cont = case L.uncons tok of
472	Just (x,cs) \| x==c -> cont True $ next 0 cs	489	Just (x,cs) \| x==c -> cont True $ next 0 cs