1 (* Title: Tools/Code/code_haskell.ML
2 Author: Florian Haftmann, TU Muenchen
4 Serializer for Haskell.
7 signature CODE_HASKELL =
10 val setup: theory -> theory
13 structure Code_Haskell : CODE_HASKELL =
16 val target = "Haskell";
18 open Basic_Code_Thingol;
25 (** Haskell serializer **)
27 fun print_haskell_stmt labelled_name class_syntax tyco_syntax const_syntax
28 reserved deresolve contr_classparam_typs deriving_show =
30 val deresolve_base = Long_Name.base_name o deresolve;
31 fun class_name class = case class_syntax class
32 of NONE => deresolve class
33 | SOME class => class;
34 fun print_typcontext tyvars vs = case maps (fn (v, sort) => map (pair v) sort) vs
36 | constraints => enum "," "(" ")" (
38 str (class_name class ^ " " ^ lookup_var tyvars v)) constraints)
40 fun print_typforall tyvars vs = case map fst vs
42 | vnames => str "forall " :: Pretty.breaks
43 (map (str o lookup_var tyvars) vnames) @ str "." @@ Pretty.brk 1;
44 fun print_tyco_expr tyvars fxy (tyco, tys) =
45 brackify fxy (str tyco :: map (print_typ tyvars BR) tys)
46 and print_typ tyvars fxy (tycoexpr as tyco `%% tys) = (case tyco_syntax tyco
47 of NONE => print_tyco_expr tyvars fxy (deresolve tyco, tys)
48 | SOME (i, print) => print (print_typ tyvars) fxy tys)
49 | print_typ tyvars fxy (ITyVar v) = (str o lookup_var tyvars) v;
50 fun print_typdecl tyvars (vs, tycoexpr) =
51 Pretty.block (print_typcontext tyvars vs @| print_tyco_expr tyvars NOBR tycoexpr);
52 fun print_typscheme tyvars (vs, ty) =
53 Pretty.block (print_typforall tyvars vs @ print_typcontext tyvars vs @| print_typ tyvars NOBR ty);
54 fun print_term tyvars some_thm vars fxy (IConst c) =
55 print_app tyvars some_thm vars fxy (c, [])
56 | print_term tyvars some_thm vars fxy (t as (t1 `$ t2)) =
57 (case Code_Thingol.unfold_const_app t
58 of SOME app => print_app tyvars some_thm vars fxy app
61 print_term tyvars some_thm vars NOBR t1,
62 print_term tyvars some_thm vars BR t2
64 | print_term tyvars some_thm vars fxy (IVar NONE) =
66 | print_term tyvars some_thm vars fxy (IVar (SOME v)) =
67 (str o lookup_var vars) v
68 | print_term tyvars some_thm vars fxy (t as _ `|=> _) =
70 val (binds, t') = Code_Thingol.unfold_pat_abs t;
71 val (ps, vars') = fold_map (print_bind tyvars some_thm BR o fst) binds vars;
72 in brackets (str "\\" :: ps @ str "->" @@ print_term tyvars some_thm vars' NOBR t') end
73 | print_term tyvars some_thm vars fxy (ICase (cases as (_, t0))) =
74 (case Code_Thingol.unfold_const_app t0
75 of SOME (c_ts as ((c, _), _)) => if is_none (const_syntax c)
76 then print_case tyvars some_thm vars fxy cases
77 else print_app tyvars some_thm vars fxy c_ts
78 | NONE => print_case tyvars some_thm vars fxy cases)
79 and print_app_expr tyvars some_thm vars ((c, (_, function_typs)), ts) = case contr_classparam_typs c
80 of [] => (str o deresolve) c :: map (print_term tyvars some_thm vars BR) ts
82 val ts_fingerprint = ts ~~ take (length ts) fingerprint;
83 val needs_annotation = forall (fn (_, NONE) => true | (t, SOME _) =>
84 (not o Code_Thingol.locally_monomorphic) t) ts_fingerprint;
85 fun print_term_anno (t, NONE) _ = print_term tyvars some_thm vars BR t
86 | print_term_anno (t, SOME _) ty =
87 brackets [print_term tyvars some_thm vars NOBR t, str "::", print_typ tyvars NOBR ty];
89 if needs_annotation then
90 (str o deresolve) c :: map2 print_term_anno ts_fingerprint (take (length ts) function_typs)
91 else (str o deresolve) c :: map (print_term tyvars some_thm vars BR) ts
93 and print_app tyvars = gen_print_app (print_app_expr tyvars) (print_term tyvars) const_syntax
94 and print_bind tyvars some_thm fxy p = gen_print_bind (print_term tyvars) some_thm fxy p
95 and print_case tyvars some_thm vars fxy (cases as ((_, [_]), _)) =
97 val (binds, body) = Code_Thingol.unfold_let (ICase cases);
98 fun print_match ((pat, ty), t) vars =
100 |> print_bind tyvars some_thm BR pat
101 |>> (fn p => semicolon [p, str "=", print_term tyvars some_thm vars NOBR t])
102 val (ps, vars') = fold_map print_match binds vars;
103 in brackify_block fxy (str "let {")
105 (concat [str "}", str "in", print_term tyvars some_thm vars' NOBR body])
107 | print_case tyvars some_thm vars fxy (((t, ty), clauses as _ :: _), _) =
109 fun print_select (pat, body) =
111 val (p, vars') = print_bind tyvars some_thm NOBR pat vars;
112 in semicolon [p, str "->", print_term tyvars some_thm vars' NOBR body] end;
113 in Pretty.block_enclose
114 (concat [str "(case", print_term tyvars some_thm vars NOBR t, str "of", str "{"], str "})")
115 (map print_select clauses)
117 | print_case tyvars some_thm vars fxy ((_, []), _) =
118 (brackify fxy o Pretty.breaks o map str) ["error", "\"empty case\""];
119 fun print_stmt (name, Code_Thingol.Fun (_, (((vs, ty), raw_eqs), _))) =
121 val tyvars = intro_vars (map fst vs) reserved;
124 (str o deresolve_base) name
125 :: map str (replicate n "_")
128 @@ (str o ML_Syntax.print_string
129 o Long_Name.base_name o Long_Name.qualifier) name
131 fun print_eqn ((ts, t), (some_thm, _)) =
133 val consts = fold Code_Thingol.add_constnames (t :: ts) [];
136 (is_none o const_syntax) deresolve consts
137 |> intro_vars ((fold o Code_Thingol.fold_varnames)
138 (insert (op =)) ts []);
141 (str o deresolve_base) name
142 :: map (print_term tyvars some_thm vars BR) ts
144 @@ print_term tyvars some_thm vars NOBR t
150 (str o suffix " ::" o deresolve_base) name,
151 print_typscheme tyvars (vs, ty)
153 :: (case filter (snd o snd) raw_eqs
154 of [] => [print_err ((length o fst o Code_Thingol.unfold_fun) ty)]
155 | eqs => map print_eqn eqs)
158 | print_stmt (name, Code_Thingol.Datatype (_, (vs, []))) =
160 val tyvars = intro_vars (map fst vs) reserved;
164 print_typdecl tyvars (vs, (deresolve_base name, map (ITyVar o fst) vs))
167 | print_stmt (name, Code_Thingol.Datatype (_, (vs, [((co, _), [ty])]))) =
169 val tyvars = intro_vars (map fst vs) reserved;
173 :: print_typdecl tyvars (vs, (deresolve_base name, map (ITyVar o fst) vs))
175 :: (str o deresolve_base) co
176 :: print_typ tyvars BR ty
177 :: (if deriving_show name then [str "deriving (Read, Show)"] else [])
180 | print_stmt (name, Code_Thingol.Datatype (_, (vs, co :: cos))) =
182 val tyvars = intro_vars (map fst vs) reserved;
183 fun print_co ((co, _), tys) =
185 (str o deresolve_base) co
186 :: map (print_typ tyvars BR) tys
191 :: print_typdecl tyvars (vs, (deresolve_base name, map (ITyVar o fst) vs))
194 :: map ((fn p => Pretty.block [str "| ", p]) o print_co) cos
195 @ (if deriving_show name then [str "deriving (Read, Show)"] else [])
198 | print_stmt (name, Code_Thingol.Class (_, (v, (super_classes, classparams)))) =
200 val tyvars = intro_vars [v] reserved;
201 fun print_classparam (classparam, ty) =
203 (str o deresolve_base) classparam,
205 print_typ tyvars NOBR ty
208 Pretty.block_enclose (
211 Pretty.block (print_typcontext tyvars [(v, map fst super_classes)]),
212 str (deresolve_base name ^ " " ^ lookup_var tyvars v),
216 ) (map print_classparam classparams)
218 | print_stmt (_, Code_Thingol.Classinst ((class, (tyco, vs)), (_, (classparam_instances, _)))) =
220 val tyvars = intro_vars (map fst vs) reserved;
221 fun requires_args classparam = case const_syntax classparam
223 | SOME (Code_Printer.Plain_const_syntax _) => 0
224 | SOME (Code_Printer.Complex_const_syntax (k,_ )) => k;
225 fun print_classparam_instance ((classparam, const), (thm, _)) =
226 case requires_args classparam
228 (str o deresolve_base) classparam,
230 print_app tyvars (SOME thm) reserved NOBR (const, [])
234 val (c, (_, tys)) = const;
235 val (vs, rhs) = (apfst o map) fst
236 (Code_Thingol.unfold_abs (Code_Thingol.eta_expand k (const, [])));
237 val s = if (is_some o const_syntax) c
238 then NONE else (SOME o Long_Name.base_name o deresolve) c;
240 |> intro_vars (map_filter I (s :: vs));
241 val lhs = IConst (classparam, (([], []), tys)) `$$ map IVar vs;
242 (*dictionaries are not relevant at this late stage*)
245 print_term tyvars (SOME thm) vars NOBR lhs,
247 print_term tyvars (SOME thm) vars NOBR rhs
251 Pretty.block_enclose (
254 Pretty.block (print_typcontext tyvars vs),
255 str (class_name class ^ " "),
256 print_typ tyvars BR (tyco `%% map (ITyVar o fst) vs),
260 ) (map print_classparam_instance classparam_instances)
264 fun haskell_program_of_program labelled_name module_prefix reserved module_alias program =
266 val reserved = Name.make_context reserved;
267 val mk_name_module = mk_name_module reserved module_prefix module_alias program;
268 fun add_stmt (name, (stmt, deps)) =
270 val (module_name, base) = dest_name name;
271 val module_name' = mk_name_module module_name;
272 val mk_name_stmt = yield_singleton Name.variants;
273 fun add_fun upper (nsp_fun, nsp_typ) =
275 val (base', nsp_fun') =
276 mk_name_stmt (if upper then first_upper base else base) nsp_fun
277 in (base', (nsp_fun', nsp_typ)) end;
278 fun add_typ (nsp_fun, nsp_typ) =
280 val (base', nsp_typ') = mk_name_stmt (first_upper base) nsp_typ
281 in (base', (nsp_fun, nsp_typ')) end;
282 val add_name = case stmt
283 of Code_Thingol.Fun (_, (_, SOME _)) => pair base
284 | Code_Thingol.Fun _ => add_fun false
285 | Code_Thingol.Datatype _ => add_typ
286 | Code_Thingol.Datatypecons _ => add_fun true
287 | Code_Thingol.Class _ => add_typ
288 | Code_Thingol.Classrel _ => pair base
289 | Code_Thingol.Classparam _ => add_fun false
290 | Code_Thingol.Classinst _ => pair base;
291 fun add_stmt' base' = case stmt
292 of Code_Thingol.Fun (_, (_, SOME _)) =>
294 | Code_Thingol.Datatypecons _ =>
295 cons (name, (Long_Name.append module_name' base', NONE))
296 | Code_Thingol.Classrel _ => I
297 | Code_Thingol.Classparam _ =>
298 cons (name, (Long_Name.append module_name' base', NONE))
299 | _ => cons (name, (Long_Name.append module_name' base', SOME stmt));
301 Symtab.map_default (module_name', ([], ([], (reserved, reserved))))
302 (apfst (fold (insert (op = : string * string -> bool)) deps))
303 #> `(fn program => add_name ((snd o snd o the o Symtab.lookup program) module_name'))
304 #-> (fn (base', names) =>
305 (Symtab.map_entry module_name' o apsnd) (fn (stmts, _) =>
306 (add_stmt' base' stmts, names)))
308 val hs_program = fold add_stmt (AList.make (fn name =>
309 (Graph.get_node program name, Graph.imm_succs program name))
310 (Graph.strong_conn program |> flat)) Symtab.empty;
311 fun deresolver name = (fst o the o AList.lookup (op =) ((fst o snd o the
312 o Symtab.lookup hs_program) ((mk_name_module o fst o dest_name) name))) name
313 handle Option => error ("Unknown statement name: " ^ labelled_name name);
314 in (deresolver, hs_program) end;
316 fun serialize_haskell module_prefix string_classes { labelled_name,
317 reserved_syms, includes, single_module, module_alias,
318 class_syntax, tyco_syntax, const_syntax, program,
319 names, presentation_names } =
321 val reserved = fold (insert (op =) o fst) includes reserved_syms;
322 val (deresolver, hs_program) = haskell_program_of_program labelled_name
323 module_prefix reserved module_alias program;
324 val contr_classparam_typs = Code_Thingol.contr_classparam_typs program;
325 fun deriving_show tyco =
327 fun deriv _ "fun" = false
328 | deriv tycos tyco = not (tyco = Code_Thingol.fun_tyco)
329 andalso (member (op =) tycos tyco
330 orelse case try (Graph.get_node program) tyco
331 of SOME (Code_Thingol.Datatype (_, (_, cs))) => forall (deriv' (tyco :: tycos))
334 and deriv' tycos (tyco `%% tys) = deriv tycos tyco
335 andalso forall (deriv' tycos) tys
336 | deriv' _ (ITyVar _) = true
337 in deriv [] tyco end;
338 val reserved = make_vars reserved;
339 fun print_stmt qualified = print_haskell_stmt labelled_name
340 class_syntax tyco_syntax const_syntax reserved
341 (if qualified then deresolver else Long_Name.base_name o deresolver)
342 contr_classparam_typs
343 (if string_classes then deriving_show else K false);
344 fun print_module name content =
345 (name, Pretty.chunks2 [
346 str ("module " ^ name ^ " where {"),
350 fun serialize_module1 (module_name', (deps, (stmts, _))) =
352 val stmt_names = map fst stmts;
353 val qualified = not single_module;
354 val imports = subtract (op =) stmt_names deps
356 |> map_filter (try deresolver)
357 |> map Long_Name.qualifier
359 fun print_import_include (name, _) = str ("import qualified " ^ name ^ ";");
360 fun print_import_module name = str ((if qualified
361 then "import qualified "
362 else "import ") ^ name ^ ";");
363 val import_ps = map print_import_include includes @ map print_import_module imports
364 val content = Pretty.chunks2 ((if null import_ps then [] else [Pretty.chunks import_ps])
366 (fn (name, (_, SOME stmt)) => SOME (print_stmt qualified (name, stmt))
367 | (_, (_, NONE)) => NONE) stmts
369 in print_module module_name' content end;
370 fun serialize_module2 (_, (_, (stmts, _))) = Pretty.chunks2 (map_filter
371 (fn (name, (_, SOME stmt)) => if null presentation_names
372 orelse member (op =) presentation_names name
373 then SOME (print_stmt false (name, stmt))
375 | (_, (_, NONE)) => NONE) stmts);
376 val serialize_module =
377 if null presentation_names then serialize_module1 else pair "" o serialize_module2;
378 fun write_module width (SOME destination) (modlname, content) =
380 val _ = File.check destination;
381 val filename = case modlname
382 of "" => Path.explode "Main.hs"
383 | _ => (Path.ext "hs" o Path.explode o implode o separate "/"
384 o Long_Name.explode) modlname;
385 val pathname = Path.append destination filename;
386 val _ = File.mkdir_leaf (Path.dir pathname);
387 in File.write pathname
388 ("{-# OPTIONS_GHC -fglasgow-exts #-}\n\n"
389 ^ string_of_pretty width content)
391 | write_module width NONE (_, content) = writeln_pretty width content;
393 Code_Target.serialization
394 (fn width => fn destination => K () o map (write_module width destination))
395 (fn width => rpair [] o cat_lines o map (string_of_pretty width o snd))
396 (map (uncurry print_module) includes
397 @ map serialize_module (Symtab.dest hs_program))
403 val s = ML_Syntax.print_char c;
404 in if s = "'" then "\\'" else s end;
405 fun numeral_haskell k = if k >= 0 then string_of_int k
406 else Library.enclose "(" ")" (signed_string_of_int k);
408 literal_char = Library.enclose "'" "'" o char_haskell,
409 literal_string = quote o translate_string char_haskell,
410 literal_numeral = numeral_haskell,
411 literal_positive_numeral = numeral_haskell,
412 literal_alternative_numeral = numeral_haskell,
413 literal_naive_numeral = numeral_haskell,
414 literal_list = enum "," "[" "]",
415 infix_cons = (5, ":")
419 (** optional monad syntax **)
421 fun pretty_haskell_monad c_bind =
423 fun dest_bind t1 t2 = case Code_Thingol.split_pat_abs t2
424 of SOME ((pat, ty), t') =>
425 SOME ((SOME ((pat, ty), true), t1), t')
427 fun dest_monad c_bind_name (IConst (c, _) `$ t1 `$ t2) =
428 if c = c_bind_name then dest_bind t1 t2
430 | dest_monad _ t = case Code_Thingol.split_let t
431 of SOME (((pat, ty), tbind), t') =>
432 SOME ((SOME ((pat, ty), false), tbind), t')
434 fun implode_monad c_bind_name = Code_Thingol.unfoldr (dest_monad c_bind_name);
435 fun print_monad print_bind print_term (NONE, t) vars =
436 (semicolon [print_term vars NOBR t], vars)
437 | print_monad print_bind print_term (SOME ((bind, _), true), t) vars = vars
438 |> print_bind NOBR bind
439 |>> (fn p => semicolon [p, str "<-", print_term vars NOBR t])
440 | print_monad print_bind print_term (SOME ((bind, _), false), t) vars = vars
441 |> print_bind NOBR bind
442 |>> (fn p => semicolon [str "let", str "{", p, str "=", print_term vars NOBR t, str "}"]);
443 fun pretty _ [c_bind'] print_term thm vars fxy [(t1, _), (t2, _)] = case dest_bind t1 t2
444 of SOME (bind, t') => let
445 val (binds, t'') = implode_monad c_bind' t'
446 val (ps, vars') = fold_map (print_monad (gen_print_bind (K print_term) thm) print_term)
447 (bind :: binds) vars;
449 (brackify fxy o single o enclose "do { " " }" o Pretty.breaks)
450 (ps @| print_term vars' NOBR t'')
452 | NONE => brackify_infix (1, L) fxy
453 (print_term vars (INFX (1, L)) t1, str ">>=", print_term vars (INFX (1, X)) t2)
454 in (2, ([c_bind], pretty)) end;
456 fun add_monad target' raw_c_bind thy =
458 val c_bind = Code.read_const thy raw_c_bind;
459 in if target = target' then
461 |> Code_Target.add_const_syntax target c_bind
462 (SOME (Code_Printer.complex_const_syntax (pretty_haskell_monad c_bind)))
463 else error "Only Haskell target allows for monad syntax" end;
468 val isar_serializer =
469 Code_Target.parse_args (Scan.option (Args.$$$ "root" -- Args.colon |-- Args.name)
470 -- Scan.optional (Args.$$$ "string_classes" >> K true) false
471 >> (fn (module_prefix, string_classes) =>
472 serialize_haskell module_prefix string_classes));
475 Outer_Syntax.command "code_monad" "define code syntax for monads" Keyword.thy_decl (
476 Parse.term_group -- Parse.name >> (fn (raw_bind, target) =>
477 Toplevel.theory (add_monad target raw_bind))
481 Code_Target.add_target
482 (target, { serializer = isar_serializer, literals = literals,
483 check = { env_var = "EXEC_GHC", make_destination = I,
484 make_command = fn ghc => fn module_name =>
485 ghc ^ " -fglasgow-exts -odir build -hidir build -stubdir build -e \"\" " ^ module_name ^ ".hs" } })
486 #> Code_Target.add_tyco_syntax target "fun" (SOME (2, fn print_typ => fn fxy => fn [ty1, ty2] =>
487 brackify_infix (1, R) fxy (
488 print_typ (INFX (1, X)) ty1,
490 print_typ (INFX (1, R)) ty2
492 #> fold (Code_Target.add_reserved target) [
493 "hiding", "deriving", "where", "case", "of", "infix", "infixl", "infixr",
494 "import", "default", "forall", "let", "in", "class", "qualified", "data",
495 "newtype", "instance", "if", "then", "else", "type", "as", "do", "module"
497 #> fold (Code_Target.add_reserved target) [
498 "Prelude", "Main", "Bool", "Maybe", "Either", "Ordering", "Char", "String", "Int",
499 "Integer", "Float", "Double", "Rational", "IO", "Eq", "Ord", "Enum", "Bounded",
500 "Num", "Real", "Integral", "Fractional", "Floating", "RealFloat", "Monad", "Functor",
501 "AlreadyExists", "ArithException", "ArrayException", "AssertionFailed", "AsyncException",
502 "BlockedOnDeadMVar", "Deadlock", "Denormal", "DivideByZero", "DotNetException", "DynException",
503 "Dynamic", "EOF", "EQ", "EmptyRec", "ErrorCall", "ExitException", "ExitFailure",
504 "ExitSuccess", "False", "GT", "HeapOverflow",
505 "IOError", "IOException", "IllegalOperation",
506 "IndexOutOfBounds", "Just", "Key", "LT", "Left", "LossOfPrecision", "NoMethodError",
507 "NoSuchThing", "NonTermination", "Nothing", "Obj", "OtherError", "Overflow",
508 "PatternMatchFail", "PermissionDenied", "ProtocolError", "RecConError", "RecSelError",
509 "RecUpdError", "ResourceBusy", "ResourceExhausted", "Right", "StackOverflow",
510 "ThreadKilled", "True", "TyCon", "TypeRep", "UndefinedElement", "Underflow",
511 "UnsupportedOperation", "UserError", "abs", "absReal", "acos", "acosh", "all",
512 "and", "any", "appendFile", "asTypeOf", "asciiTab", "asin", "asinh", "atan",
513 "atan2", "atanh", "basicIORun", "blockIO", "boundedEnumFrom", "boundedEnumFromThen",
514 "boundedEnumFromThenTo", "boundedEnumFromTo", "boundedPred", "boundedSucc", "break",
515 "catch", "catchException", "ceiling", "compare", "concat", "concatMap", "const",
516 "cos", "cosh", "curry", "cycle", "decodeFloat", "denominator", "div", "divMod",
517 "doubleToRatio", "doubleToRational", "drop", "dropWhile", "either", "elem",
518 "emptyRec", "encodeFloat", "enumFrom", "enumFromThen", "enumFromThenTo",
519 "enumFromTo", "error", "even", "exp", "exponent", "fail", "filter", "flip",
520 "floatDigits", "floatProperFraction", "floatRadix", "floatRange", "floatToRational",
521 "floor", "fmap", "foldl", "foldl'", "foldl1", "foldr", "foldr1", "fromDouble",
522 "fromEnum", "fromEnum_0", "fromInt", "fromInteger", "fromIntegral", "fromObj",
523 "fromRational", "fst", "gcd", "getChar", "getContents", "getLine", "head",
524 "id", "inRange", "index", "init", "intToRatio", "interact", "ioError", "isAlpha",
525 "isAlphaNum", "isDenormalized", "isDigit", "isHexDigit", "isIEEE", "isInfinite",
526 "isLower", "isNaN", "isNegativeZero", "isOctDigit", "isSpace", "isUpper", "iterate", "iterate'",
527 "last", "lcm", "length", "lex", "lexDigits", "lexLitChar", "lexmatch", "lines", "log",
528 "logBase", "lookup", "loop", "map", "mapM", "mapM_", "max", "maxBound", "maximum",
529 "maybe", "min", "minBound", "minimum", "mod", "negate", "nonnull", "not", "notElem",
530 "null", "numerator", "numericEnumFrom", "numericEnumFromThen", "numericEnumFromThenTo",
531 "numericEnumFromTo", "odd", "or", "otherwise", "pi", "pred",
532 "print", "product", "properFraction", "protectEsc", "putChar", "putStr", "putStrLn",
533 "quot", "quotRem", "range", "rangeSize", "rationalToDouble", "rationalToFloat",
534 "rationalToRealFloat", "read", "readDec", "readField", "readFieldName", "readFile",
535 "readFloat", "readHex", "readIO", "readInt", "readList", "readLitChar", "readLn",
536 "readOct", "readParen", "readSigned", "reads", "readsPrec", "realFloatToRational",
537 "realToFrac", "recip", "reduce", "rem", "repeat", "replicate", "return", "reverse",
538 "round", "scaleFloat", "scanl", "scanl1", "scanr", "scanr1", "seq", "sequence",
539 "sequence_", "show", "showChar", "showException", "showField", "showList",
540 "showLitChar", "showParen", "showString", "shows", "showsPrec", "significand",
541 "signum", "signumReal", "sin", "sinh", "snd", "span", "splitAt", "sqrt", "subtract",
542 "succ", "sum", "tail", "take", "takeWhile", "takeWhile1", "tan", "tanh", "threadToIOResult",
543 "throw", "toEnum", "toInt", "toInteger", "toObj", "toRational", "truncate", "uncurry",
544 "undefined", "unlines", "unsafeCoerce", "unsafeIndex", "unsafeRangeSize", "until", "unwords",
545 "unzip", "unzip3", "userError", "words", "writeFile", "zip", "zip3", "zipWith", "zipWith3"
546 ] (*due to weird handling of ':', we can't do anything else than to import *all* prelude symbols*);