[-*- Mode: emacs-lisp -*-]
[-----grammar
 (gz start (prog))
 (gz prog (module))
 (gz module (id language-pragma-opt exports imports topdecl-star
                ::pr("[[language-pragma-opt]]"
      "{-\n"
      "Copyright 2011 Ken Takusagawa\n"
      "This program is free software: you can redistribute it and/or modify\n"
      "it under the terms of the GNU Affero General Public License as published by\n"
      "the Free Software Foundation, either version 3 of the License, or\n"
      "(at your option) any later version.\n\n"
      "This program is distributed in the hope that it will be useful,\n"
      "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
      "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
      "GNU General Public License for more details.\n\n"
      "You should have received a copy of the GNU Affero General Public License\n"
      "along with this program.  If not, see <http://www.gnu.org/licenses/>.\n"
      "-}\n\n"
                     "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('(',', ',')')]]")) (:export-everything ::pr("")))
 (gz export (id)
     (f :module-export id j ::pr("module [[id]]"))
     )
 (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  id-non-plus 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)  decls j
                 ::pr ("instance [[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}" (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(" 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(constr-star ::pr("[[constr-star('',' | ','')]]"))

     )
 (gz field-type-and-param (f param type j
                             ::pr("[[param]] :: [[type]]")))
 (gz type-and-param ( f param type j ::pr("[[type]]")))
 (gz constr(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')]]}\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 positional-constructor ["this one is sketchy"]
     (type-ctor ::pr("[[type-ctor]]"))
     (f   type-ctor typepls-opt j
          ::pr("[[type-ctor]][[typepls-opt]]"))
     (f :tuple type-plus j
        ::pr("[[type-plus('(',', ',')')]]"))
     )
 (gz pattern
     (id)
     (f  pattern-ctor pattern-star j
         ::pr ("([[pattern-ctor]] [[pattern-star('',' ','')]])"))

     (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"]
          )

 (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))
 (gz typepls (paren-type-plus))
 (gz paren-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 ("(:)")) [(:nil ::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 :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 :case expr alt-star :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-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-star :else (underbar ::is expr) 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')]]}\n in [[expr]])"))
     (f :rlet expr decl-star j
        ::pr("(let {[[decl-star('\n',';\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-star j ::pr("[[expr-star('(',':',')')]]"))
     (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 type expr j ::pr("[[pattern]] :: [[type]] <- [[expr]];"))
     (f :let-many decl-star j ::pr ("let {[[decl-star('\n',';\n','\n')]]};"))
     (f :dlet id type expr j ::pr ("let {" "  [[id]] :: [[type]];" "  [[id]] = [[expr]];" "};"))
     )
 (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 ("\n[[pred-expr-star('','','')]] [[where-opt]]"
              )))
 (gz pred-expr ( f (pred ::is expr) (do ::is expr) j
                   ::pr ("| [[pred]]\n -> [[do]]\n")))
 (gz where (:where decls ::pr ("where [[decls]]")))

 (gz decl-mark (":"))
 (gz haddock ( :doc f docline-star j 
                    ::pr ("[[docline-star('\n\x7b\x2d |','\n',' \x2d\x7d\n')]]")))
 (gz docline (astring))
 ]



Main :language-pragma
(
 ScopedTypeVariables
 [GeneralizedNewtypeDeriving]
 [RankNTypes]
 )
(main)
(
 Data.List
 Data.Maybe
 Control.Monad
)

(: main :fun (IO :unit) ()
   (:do
    (putStrLn "=============test1")
    test1
    (putStrLn "=============test2")
    test
   ))


(: Btape :type-synonym (Listzipper Bool))
(: btape-initial :fun Btape ()
   (infinite-repeat False))
(: siblings-blank :fun (Siblings a) ((x a))
   (:mtuple (repeat x)(repeat x)))
(: infinite-repeat :fun (Listzipper a)((x a))
   (Listzipper x (siblings-blank x)))
(: tape-left :fun (Listzipper a)
   (((Listzipper middle (:ptuple (:cons h t)right))(Listzipper a)))
   (Listzipper h (:mtuple t (:mcons middle right))))
(: tape-right :fun (Listzipper a)
   (((Listzipper middle (:ptuple left (:cons h t)))(Listzipper a)))
   (Listzipper h (:mtuple (:mcons middle left)t)))
(: Tt :type-synonym (Listzipper Btape))
(: tt-initial :fun Tt ()(infinite-repeat btape-initial))


(: left :fun Zipper (((Zipper n parents)Zipper))
   (Zipper (tape-left n) parents))
(: right :fun Zipper (((Zipper n parents)Zipper))
   (Zipper (tape-right n) parents))
(: up :fun Zipper (((Zipper n (:cons parent grandparents)) Zipper))
   (Zipper (Listzipper (Internal n) parent) grandparents))
(: down :fun (m Zipper) (((Zipper(Listzipper n sibs)parents)Zipper))
   :context((Monad m))
   (:case n
          ((Internal t)(return(Zipper t(:mcons sibs parents))))
          :else (fail "cannot descend leaf")
          ))
(: jdown :fun Zipper ((z Zipper))
   (:rpipe z down fromJust))
(: get-node :fun Node (((Zipper(Listzipper n _)_)Zipper))n)
(: read-tape :fun (m Bool) ((z Zipper))
   :context((Monad m))
   (:case (get-node z)
          ((Leaf x)(return x))
          :else(fail "cannot read internal node")))
(: is-leaf :fun Bool ((n Node))
   (:case n((Leaf _)True)
          :else False))
(: write-node-bool :fun (m Node)((n Node)(x Bool)):context((Monad m))
   (:case n((Leaf _)(return(Leaf x)))
          :else (fail "error: tried to write internal node")))
(: write-tape-bool :fun (m Zipper)
   ((x Bool)((Zipper(Listzipper n sibs)parents)Zipper))
   :context((Monad m))
   (:do
    (:= new Node (write-node-bool n x))
    (return (Zipper(Listzipper new sibs)parents))
    ))
(: set-tape :fun Zipper ((z Zipper))
   (:rpipe z (write-tape-bool True) fromJust))
[never have to worry about empty lists for infinite lists]
(: Listzipper :data :args(a) (Listzipper a (Siblings a)))
[not enforcing that all nodes at the same level are the same kind]
(: Node :data (Leaf Bool)(Internal Tape))
(: Tape :type-synonym (Listzipper Node))
(: Zipper :data (Zipper Tape (:list (Siblings Node))))
(: Siblings :type-synonym :args(a) (:tuple(:list a)(:list a)))

(: empty-regular-tape :fun Tape ()(infinite-repeat (Leaf False)))
(: first-siblings :fun (Siblings Node)()
   (siblings-blank (Internal empty-regular-tape)))
(: higher-tape :fun Tape ((t Tape))
   (infinite-repeat (Internal t)))
(: get-sibs :fun (Siblings a)(((Listzipper _ sibs)(Listzipper a)))sibs)
(: initial-sibs :fun (:list (Siblings Node))()
   (:rpipe empty-regular-tape
           (iterate higher-tape)
           tail
           (map get-sibs)))
(: initial-zipper :fun :doc
   ("Infinite tapes of Falses are all on the same bottom level."
    "Every level up, each cell is itself an infinite tape.")
   Zipper ()
   (Zipper empty-regular-tape initial-sibs))

(: test1 :fun (IO :unit)()
   (:do
    (:dlet z Zipper initial-zipper)
    (:let-many
     (: p :fun (IO :unit)((z Zipper))
        [(:rpipe z read-tape print)]
        (print
         (:ty (Maybe Bool) (read-tape z)))
        ))
    (:rpipe z p)
    (:rpipe z left p)
    (:rpipe z up p)
    (:rpipe z up jdown p)
    (:rpipe z left up jdown p)
    (:rpipe z up left jdown p)
    (:rpipe z set-tape up up jdown jdown p)
    (:rpipe z set-tape left right p)
    (:rpipe z set-tape left up left up left right jdown right jdown right p)
    ))

(: not-flat-sibs :fun (Siblings Node)()
   (siblings-blank (Leaf False)))

(: not-flat-initial-zipper :fun
   :doc("The current tape is at the base on an infinite tree."
        "Going up yields a tape with Falses on either side, and an infinite tape under the current cell")
   Zipper ()
   (:rpipe False Leaf siblings-blank repeat (Zipper empty-regular-tape))
   )
(: write-tape :fun :doc ("Replace the current cell with an empty subtape") Zipper
   (((Zipper(Listzipper _ sibs)parents)Zipper))
   (Zipper(Listzipper (Internal empty-regular-tape) sibs)parents))

(: test :fun (IO :unit)()
   (:do
    (:dlet z Zipper not-flat-initial-zipper)
    (:let-many
     (: p :fun (IO :unit)((z Zipper))
        (print
         (:ty (Maybe Bool)(read-tape z)))))
    (:rpipe z p)
    (:rpipe z write-tape p)
    (:rpipe z left set-tape right write-tape jdown p)
    (:rpipe z left set-tape right write-tape jdown up left p)
    (:rpipe z left set-tape up left up right left jdown right jdown p)
    ))