[-*- emacs-lisp -*-]
[
 Copyright 2012 Ken Takusagawa
           
           This program is free software: you can redistribute it and/or modify
           it under the terms of the GNU General Public License as published by
           the Free Software Foundation, either version 3 of the License, or
           (at your option) any later version.
           
           This program is distributed in the hope that it will be useful,
           but WITHOUT ANY WARRANTY; without even the implied warranty of
           MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
           GNU General Public License for more details.
           
           You should have received a copy of the GNU General Public License
           along with this program.  If not, see <http://www.gnu.org/licenses/>.
]

[-----grammar
 (gz start (prog))
 (gz prog (module))
 (gz module (id language-pragma-opt exports imports topdecl-star
                ::pr("[[language-pragma-opt]]module [[id]] [[exports]] where {\n[[imports]]\n"
                     "[[topdecl-star('',';\n\n','\n')]]}\n")))
 (gz language-pragma ( :language-pragma f id-non-star j
                                        ::pr
                                        ("{-# LANGUAGE [[id-non-star('',',','')]] #-}\n")))
 (gz exports
     (f export-star j
                ::pr("[[export-star('\n  ( ','\n  , ','\n  )')]]"))
     (:export-everything ::pr("")))
 (gz export
     (id)
     (f :module-export id j ::pr("module [[id]]"))
     (f :type-export id constructors-export j ::pr("[[id]][[constructors-export]]"))
     )
 (gz constructors-export
     (:all-constructors ::pr("(..)"))
     (id-non-star ::pr("[[id-non-star('(',',',')')]]"))
     )
 (gz imports (f import-star j
                ::pr("[[import-star('',';\n',';\n')]]")))
 (gz import(id ::pr( "import [[id]]"))
     (f :qualified (original-name ::is id) (new-name ::is id) j
        ::pr ( "import qualified [[original-name]] as [[new-name]]"))
     (f :specific id id-non-star j
        ::pr ("import [[id]][[id-non-star('(',',',')')]]"))
     (f :hiding import id-non-star j
        ::pr("[[import]] hiding[[id-non-star('(',',',')')]]")
        [dunno if this will work for complicated cases]
        ))
 (gz type-class (f decl-mark (class-name ::is id) :type-class context-opt f id-non-plus j type-class-decl-star j
                   ::pr("class [[context-opt]][[class-name]] [[id-non-plus('',' ','')]] where{\n"
                        "[[type-class-decl-star('',';\n','\n')]]}")))
 (gz topdecl (decl) (data)(type-synonym)(newtype)(instance)(type-class))
 (gz type-class-decl (type-signature)(decl))
 (gz type-signature (f decl-mark name :tysig ret-type-and-params j
                       ::pr("[[name]] :: [[ret-type-and-params]]")))
 (gz instance (f :instance (type ::is id) (name ::is simpletype)  context-opt decls j
                 ::pr ("instance [[context-opt]] [[type]] ([[name]]) where [[decls]]")))
 [(gz instance (f :instance context-opt (type ::is id) simpletype-plus :x decls j
                  ::pr ("instance [[context-opt]][[type]] [[simpletype-plus('(',')(',')')]] where [[decls]]")))]
 (gz newtype (f decl-mark (name ::is id) :newtype type-vars-opt  constr-or-wrap deriving-opt j
                ::pr("newtype [[name]] [[type-vars-opt]] = [[constr-or-wrap{my_name}]][[deriving-opt]]")))
 (gz constr-or-wrap ::gets "tr-id*{name}" (outer-constr)(wrap-constr ::pr("[[wrap-constr{name}]]")))
 (gz wrap-constr ::gets "tr-id*{name}"
     ( :wrap id
             ::pr(
                  (::c "name->print();")
                  " {un"
                  (::c "name->print();")
                  " :: [[id]]}")))

 (gz deriving (:deriving f id-non-plus j
                         ::pr("\n  deriving [[id-non-plus('(',', ',')')]]")))
 (gz id-non (id))
 (gz type-synonym (f decl-mark id :type-synonym type-vars-opt type j
                     ::pr("type [[id]] [[type-vars-opt]] = [[type]]")))
 (gz data (f decl-mark id :data type-vars-opt constrs deriving-opt j ::pr("data [[id]] [[type-vars-opt]] = [[constrs]][[deriving-opt]]")))
 (gz simpletype (f id-non-plus j ::pr ("[[id-non-plus('',' ','')]]")))
 (gz type-vars (:args f id-non-star j ::pr ("[[id-non-star('',' ','')]]")))
 (gz constrs(outer-constr-star ::pr("[[outer-constr-star('','\n  | ','')]]")))
 (gz field-type-and-param (f param type j
                             ::pr("[[param]] :: [[type]]")))
 (gz type-and-param ( f param type j ::pr("[[type]]")))
 (gz outer-constr(outer-positional-constructor) (field-label-constructor) )
 (gz field-label-constructor(f type-ctor :field field-type-and-param-star j
                               ::pr("[[type-ctor]][[field-type-and-param-star('{',', ','}')]]")))
 (gz decls (  decl-star  ::pr("{[[decl-star('\n',';\n','\n')]]}")))
 (gz context (:context f a-context-plus j ::pr
                       ("[[a-context-plus('(',', ',')')]] => ")))
 (gz a-context [(f (type ::is id) id-non-plus j
                   ::pr("[[type]] [[id-non-plus('',' ','')]]"))]
     (f (class ::is id) type-plus j
        ::pr("[[class]] [[type-plus('',' ','')]]"))
     )
 (gz forall (:forall f id-non-plus j
                     ::pr("forall [[id-non-plus('',' ','')]] . ")))
 (gz ret-type-and-params
     (type f type-and-param-star j forall-opt context-opt
           ::pr("[[forall-opt]][[context-opt]][[type-and-param-star('',' \x2d> ','')]]"
                (::c "if(my_type_and_param_star->v.size()>0)out(' \x2d> ');")
                "[[type]]")))

 (gz decl (f decl-mark name :fun haddock-opt ret-type-and-params  expr j
             ::pr("[[haddock-opt]]"
                  "[[name]] :: [[ret-type-and-params]];\n"
                  "[[name]]"
                  (::c "for(many_trees::const_iterator pos = my_ret_type_and_params->my_type_and_param_star->v.begin();pos!= my_ret_type_and_params->my_type_and_param_star->v.end();++pos){"
                       "const tr_type_and_param* t=dynamic_cast<const tr_type_and_param*>(*pos);"
                       "assert(t);"
                       "out(' ');"
                       "t->my_param->print();" "}")
                  " = [[expr]]"))
     (f decl-mark name :fun :no-sig ret-type-and-params  expr j
        ::pr("[[name]]"
             (::c "for(many_trees::const_iterator pos = my_ret_type_and_params->my_type_and_param_star->v.begin();pos!= my_ret_type_and_params->my_type_and_param_star->v.end();++pos){"
                  "const tr_type_and_param* t=dynamic_cast<const tr_type_and_param*>(*pos);"
                  "assert(t);"
                  "out(' ');"
                  "t->my_param->print();" "}")
             " = [[expr]]"))
     (f decl-mark name :simple  expr j
        ::pr("[[name]] = [[expr]]"))
     )
 (gz name (id))
 (gz outer-positional-constructor ["this one is sketchy"]
     (type-ctor ::pr("[[type-ctor]]"))
     (f type-ctor type-star j
        ::pr("[[type-ctor]][[type-star(' ',' ','')]]"))
     (f :tuple type-plus j
        ::pr("[[type-plus('(',', ',')')]]"))
     )

 (gz positional-constructor ["this one is sketchy"]
     (type-ctor ::pr("[[type-ctor]]"))
     (f type-ctor type-star j
        ::pr("([[type-ctor]][[type-star(' ',' ','')]])"))
     (f :tuple type-plus j
        ::pr("[[type-plus('(',', ',')')]]"))
     )

 (gz pattern
     (id)
     ["avoid pattern-star because it causes weird spacing"]
     (f  pattern-ctor j
         ::pr ("[[pattern-ctor]]"))
     (f  pattern-ctor pattern-plus j
         ::pr ("([[pattern-ctor]] [[pattern-plus('',' ','')]])"))
     
     (f pattern-ctor :fpat f fpat-star j j
        ::pr ("([[pattern-ctor]][[fpat-star('{',', ','}')]])"))

     (f :ptuple pattern-plus j [pattern-plus cuz :nil exists for empty lists]
        ::pr("[[pattern-plus('(',', ',')')]]"))

     (f :plist pattern-plus j [pattern-plus cuz :nil exists for empty lists]
        ::pr("[[pattern-plus('\x5b',', ','\x5d')]]"))

     (f :pchar astring j ::pr("\x27[[astring]]\x27"))

     (f :pstring astring j ::pr("\x22[[astring]]\x22"))

     (f :as id pattern j ::pr("([[id]]@[[pattern]])"))

     )
 (gz pattern-ctor (id) (:cons ::pr ("(:)")) (:nil ::pr ("[]"))
     (:paren id  ::pr("([[id]])")) ["workaround for Qualified parenthesized constructors"]
     ( :v id type ::pr("([[id]] :: [[type]])"))
     )

 (gz fpat (f (variable ::is id) pattern j
             ::pr("[[variable]] = [[pattern]]")))

 (gz type (f :fn ret-type-and-params j ::pr ("([[ret-type-and-params]])"))
     (:inforall f id-non-plus j type  ::pr("(forall [[id-non-plus('',' ','')]] . [[type]])"))
     (:unit ::pr("()"))
     (positional-constructor)
     (f :strict type j  ::pr ("![[type]]"))
     )
 [(gz typepls (paren-type-plus))]
 [(gz strict-type (type ::pr( "[[type]]"))
     (f :strict type j ::pr("![[type]]"))
     [(f :generic id j ::pr (" [[id]] "))])]
 (gz type-ctor(id)(:list ::pr ("[]")) [(:nondet ::pr ("[]"))])
 (gz param (pattern))
 (gz qastring  (astring ::pr("\x22[[astring]]\x22")))

 (gz expr (id) (:mcons ::pr ("(:)"))
     (f :chain astring expr-plus j ::pr
        ([("[[expr-plus('(',' op ',')')]]")]
         "("
         (::c "for(many_trees::const_iterator pos=my_expr_plus->v.begin();pos!=my_expr_plus->v.end();++pos){")
         (::c "if(pos!=my_expr_plus->v.begin()){")
         "[[astring]]"
         (::c "}(*pos)->print();}")
         ")"
         ))
     (f :join expr-plus j ::pr("[[expr-plus('(',' >>= ',')')]]"))
     (f :cc expr-star j ::pr ("[[expr-star('(',' ++ ',')')]]"))
     (f :msum expr-star j ::pr ("[[expr-star('(',' \x60mplus\x60 ',')')]]"))
     (f :rpipe expr-plus j ::pr[("[[expr-star('(',' $ ',')')]]")]
        (["http;//gcc.gnu.org/bugzilla/show_bug.cgi?id=11729"]
         (::c "for(many_trees::reverse_iterator pos = my_expr_plus->v.rbegin();"
              "pos!=my_expr_plus->v.rend();++pos){")
         "("
         (::c "(*pos)->print();" "}")
         (::c "for(many_trees::const_iterator pos = my_expr_plus->v.begin();"
              "pos!=my_expr_plus->v.end();++pos){")
         ")"
         (::c  "}")
         ))
     (f :rcompose expr-plus j ::pr
        ("("
         (::c "for(many_trees::reverse_iterator pos = my_expr_plus->v.rbegin();"
              "pos!=my_expr_plus->v.rend();++pos){")
         (::c "if(pos!=my_expr_plus->v.rbegin())")
         " . "
         (::c "(*pos)->print();" "}")
         ")"
         ))
     (qastring)
     (f :lit astring j ::pr("[[astring]]"))
     (f :ty type expr j ::pr("([[expr]] :: [[type]])"))
     (f (fun-name ::is expr) expr-star j
        ::pr ("([[fun-name]][[expr-star(' ',' ','')]])"))
     (f :do  stmt-star  j ::pr("(do {\n[[stmt-star('  ','\n  ','\n')]]})"))
     (f :case expr  alt-star  j
        ::pr("(case [[expr]] of {\n[[alt-star('  ',';\n  ','\n')]]})"))
     (f :mzerocase expr  alt-star  j
        ::pr("(case [[expr]] of {\n[[alt-star('  ',';\n  ',';\n')]]"
             "  _ -> mzero\n"
             "})"))
     (f :case expr alt-plus :else (underbar ::is expr) j
        ["the else is there so the grammar does not have a reduce/reduce conflict"]
        ::pr("(case [[expr]] of {\n[[alt-plus('  ',';\n  ',';\n')]]"
             "  _ -> [[underbar]]\n"
             "})"))
     (f :case expr :else (underbar ::is expr) alt-star  j
        ::pr("(case [[expr]] of {\n[[alt-star('  ',';\n  ',';\n')]]"
             "  _ -> [[underbar]]\n"
             "})"))
     (f :lcase alt-star j
        ::pr("(\x5clambda_case_var ->"
             "case lambda_case_var of {\n"
             "[[alt-star('  ',';\n  ','\n')]]})"))
     (f :lcase alt-plus :else (underbar ::is expr) j
        ::pr("(\x5clambda_case_var ->"
             "case lambda_case_var of {\n"
             "[[alt-plus('  ',';\n  ',';\n')]]"
             "  _ -> [[underbar]]\n"
             "})"))
     (f :lcase :else (underbar ::is expr) alt-star j
        ::pr("(\x5clambda_case_var ->"
             "case lambda_case_var of {\n"
             "[[alt-star('  ',';\n  ',';\n')]]"
             "  _ -> [[underbar]]\n"
             "})"))
     (f :let decl-star expr j
        ::pr("(let {[[decl-star('\n',';\n','\n')]]} in [[expr]])"))
     (f :rlet expr decl-star j
        ::pr("(let {[[decl-star('\n',';\n','\n')]]} in [[expr]])"))
     (f :cfd expr assignments-star j
        ::pr("([[expr]][[assignments-star('{',', ','}')]])"))
     (f :mlist expr-star j ::pr("[[expr-star('\x5b',', ','\x5d')]]"))
     (f :cons-list expr-plus j ::pr("[[expr-plus('(',':',')')]]"))
     (f :mtuple expr-star j ::pr("[[expr-star('(',', ',')')]]"))
     (:nothing  ::pr ("()"))
     (f :lambda name ret-type-and-params expr j
        ::pr("(let {[[name]] :: [[ret-type-and-params]];\n"
             "[[name]]"
             (::c "for(many_trees::const_iterator pos = my_ret_type_and_params->my_type_and_param_star->v.begin();pos!= my_ret_type_and_params->my_type_and_param_star->v.end();++pos){"
                  "const tr_type_and_param* t=dynamic_cast<const tr_type_and_param*>(*pos);"
                  "assert(t);"
                  "out(' ');"
                  "t->my_param->print();" "}")
             " = [[expr]]} in [[name]])"))
     (f :lambda-simple id-non expr j
        [recommended only for reordering arguments to functions
                     and other simple expressions]
        [only one variable to keep it simple]
        ::pr ("(\x5c[[id-non]] -> [[expr]])"))
     (f :field-edit expr field-edit-plus j
        [plus is required by Haskell]
        ::pr("([[expr]][[field-edit-plus('{',',','}')]])"))
     )
 (gz field-edit (f id expr j ::pr ("[[id]] = [[expr]]")))

 (gz assignments (f id expr j ::pr("[[id]] = [[expr]]")))
 (gz stmt (expr ::pr("[[expr]];"))
     (f ":=" pattern expr j ::pr("[[pattern]] <- [[expr]];"))
     (f :dlet decl-star j ::pr ("let {[[decl-star('\n',';\n','\n')]]};"))
     )
 (gz alt (f  pattern expr-or-gpat j
             ::pr("[[pattern]][[expr-or-gpat]]")))
 (gz expr-or-gpat
     (expr ::pr (" -> [[expr]]"))
     (where-opt :gpats pred-expr-star [silly lookahead limitation]
                ::pr ("[[pred-expr-star('\n    ','\n    ','')]][[where-opt]]\n    "
                      )))
 (gz pred-expr ( f (pred ::is expr) (do ::is expr) j
                   ::pr ("| [[pred]] -> [[do]]")))
 (gz where (:where decls ::pr ("\n    where [[decls]]")))
 (gz decl-mark (":"))
 (gz haddock ( :doc f docline-star j
                    ::pr ("[[docline-star('\x7b\x2d |','\n',' \x2d\x7d\n')]]")))
 (gz docline (astring))
 ]

Main :language-pragma
(
 ScopedTypeVariables
 )
:export-everything

(
 (:specific Control.Monad replicateM foldM)
 (:specific Data.List intersperse)
 (:specific Control.Exception assert)
 (:specific System.Environment getArgs)
 (:specific Data.Array.IO newListArray range getBounds readArray getElems writeArray readArray IOArray)
 (:specific System.Random getStdRandom randomR StdGen mkStdGen setStdGen)

 )
(: Fdouble :type-synonym Float)
(: Coord :type-synonym (:tuple Int Int))
(: Image :type-synonym (IOArray Coord Fdouble))

(: image-bounds :fun (:tuple Coord Coord)((size Int))
   (:mtuple (:mtuple 0 0 )(:mtuple (pred size)(pred size))))
(: full :fun
   :doc("image with all pixels defined.")
   (IO Image)((rand Rand-function)(size Int))
   (:join
    (:rpipe rand getStdRandom (replicateM (* size size)))
    (newListArray (image-bounds size))))
(: Rand-function :type-synonym (:fn(:tuple Fdouble StdGen)((g StdGen))))
(: gray :fun :doc ("returns real number uniformly between 0 and 1")
   Rand-function ()
   (randomR (:mtuple 0 1)))
(: black-white :fun :doc ("returns 0 or 1") Rand-function ()
   (:let
    (: inner :fun (:tuple Int StdGen)((g StdGen))
       (randomR (:mtuple 0 1) g))
    (: convert :fun (:tuple Fdouble StdGen)((g StdGen))
       (:case (inner g)
              ((:ptuple i g2)(:mtuple (fromIntegral i) g2))))
    convert))
(: checkerboard :fun
   :doc("sets half the pixels in a checkerboard pattern")
   (IO Image)((rand Rand-function)(size Int))
   (:join
    (:rpipe (image-bounds size) range
            (mapM (init-checkerboard rand)))
    (newListArray (image-bounds size))
    ))
(: init-checkerboard :fun
   (IO Fdouble)((rand Rand-function)(c Coord))
   (:case (odd-index c)
          (False (getStdRandom rand))
          (True (return (error "checkerboard not filled")))))

(: getImageSize :fun (IO Int)((image Image))
   (:do
    (:= (:ptuple _ (:ptuple x _)) (getBounds image))
    (return (succ x))
    ))
(: odd-index :fun Bool (((:ptuple x y)Coord))
   (:case (mod (+ x y)2)
          (1 True)
          :else False))
(: wrapped-read :fun (IO Fdouble)((image Image)((:ptuple x y)Coord))
   (:do
    (:= (:ptuple _z (:ptuple xmax ymax)) (getBounds image))
    (readArray image (:mtuple (mod x (+ 1 xmax))(mod y (+ 1 ymax))))
    ))
(: coords-checkerboard :fun
   :doc("orthogonal neighbors")
   (:list Coord)(((:ptuple x y)Coord))
   (:mlist
    (:mtuple (pred x) y)
    (:mtuple (succ x) y)
    (:mtuple x (pred y))
    (:mtuple x (succ y))
    ))
(: coords-double :fun
   :doc("diagonal neighbors, forming an X")
   (:list Coord)(((:ptuple x y)Coord))
   (:do
    (:= (:plist f g) (replicateM 2(:mlist pred succ)))
    (return (:mtuple (f x)(g y)))))

(: average-read :fun (IO Fdouble)((image Image)(c(:list Coord)))
   (:do
    (:= (:v vals (:list Fdouble)) (mapM (wrapped-read image) c))
    (return (/ (sum vals) (fromIntegral(length c))))))
(: one-pixel :fun
   :doc("sets a pixel with a value averaged from given neighbors")
   (IO :unit)
   ((image Image)
    (which-neighbors(:fn(:list Coord)((c Coord))))
    (c Coord))
   (:join
    (:rpipe c
            which-neighbors
            (average-read image))
    (writeArray image c)))
(: fill-checkerboard :fun (IO :unit)((image Image))
   (:join
    (getBounds image)
    (:rcompose range (filter odd-index) return)
    (mapM- (one-pixel image coords-checkerboard))
    )
   )
(: pgm-image :fun (IO :unit)((image Image))
   (:do
    (putStrLn "P2")
    (:= (:v size Int) (getImageSize image))
    (putStrLn (:cc (show size)" "(show size)))
    (putStrLn "255")
    (:join (getElems image)(mapM- (:rcompose clip-round print)))
    ))
(: clip-round :fun Int ((x Fdouble))
   (:case (floor (* 256 x))
          (256 255)
          (i i)))

(: double-image :fun
   :doc("doubles image, leaving 3/4 pixels undefined")
   (IO Image)((image Image))
   (:do
    (:= (:v oldsize Int) (getImageSize image))
    (:dlet
     (: newsize :fun Int () (* 2 oldsize)))
    (:join
     (:rpipe (image-bounds newsize) range
             (mapM (init-double image)))
     (newListArray (image-bounds newsize)))
    ))
(: init-double :fun (IO Fdouble)((old Image)((:ptuple x y)Coord))
   (:case (:mtuple (divMod x 2)(divMod y 2))
          ((:ptuple (:ptuple sx 0)(:ptuple sy 0))
           (readArray old (:mtuple sx sy)))
          :else
          (return (error "undefined double pixel"))))
(: double-fillable-index :fun Bool (((:ptuple x y)Coord))
   (&& (== 1 (mod x 2))(== 1 (mod y 2))))
(: fill-double :fun
   :doc("fills in some undefined pixels from a recently doubled image")
   (IO :unit)((image Image))
   (:join
    (getBounds image)
    (:rcompose range (filter double-fillable-index) return)
    (mapM- (one-pixel image coords-double))))
(: auto-double :fun
   :doc("doubles the dimensions of the image, applying smoothing")
   (IO Image)((small Image))
   (:do
    (:= image (double-image small))
    (fill-double image)
    (fill-checkerboard image)
    (return image)
    ))
(: auto-checkerboard :fun (IO Image)((rand Rand-function)(size Int))
   (:do
    (:= image (checkerboard rand size))
    (fill-checkerboard image)
    (return image)))
(: multiple-smooth1 :fun (IO Image)((n Integer)(small Image))
   (:case (compare n 0)
          (EQ (return small))
          (GT (:join (auto-double small) (multiple-smooth1 (pred n))))))

(: multiple-smooth :fun (IO Image)((n Int)(small Image))
   (iterateM auto-double small n))
(: iterateM :fun (m a)((f(:fn(m a)((x a))))(start a)(n Int))
   :forall(a m)
   :context((Monad m))
   (:let
    (: inner :fun (m a)((x a)(_ :unit))
       (f x))
    (foldM inner start (replicate n :nothing))
    ))
   

(: read-rand :fun Rand-function ((s String))
   (:case s
          ((:pstring "binary")black-white)
          ((:pstring "gray")gray)
          :else
          (error "rand = {binary | gray}")
          ))
(: read-starting :fun (:fn(IO Image)((rand Rand-function)(size Int)))((s String))
   (:case s
          ((:pstring "full")full)
          ((:pstring "checkerboard")auto-checkerboard)
          :else
          (error "starting = {full | checkerboard}")
          ))

(: main :fun (IO :unit) ()
   (:do
    [(:rpipe 1 mkStdGen setStdGen)]
    (:join
     getArgs
     (:lcase
      ((:plist starting rand size iterations)
       (:join ((read-starting starting)(read-rand rand)(read size))(multiple-smooth (read iterations)) pgm-image))
      :else
      (putStrLn "starting rand size iterations")))
    ))