data Module
  | Module "module" Modid ExportDecls ImportDecls "where" "{" TopDeclList "}"

data ExportDecls
  | ExpListD "exports" "{" ExportList "}"
  | ExpAllD

data ImportDecls
  | ImpListD "imports" "{" ImportList "}"
  | ImpNoneD

data Export
  | TypeEx Con Spec
  | VarEx Var

data Import | Import Modid AsSpec

data AsSpec
  | AsAS "as" Modid
  | EmptyAS 

data Spec
  | Neither
  | Decon "(" "." ")"
  | Both "(" ".." ")"

data TopDecl
  | ExternD "extern" ExtNm Var "::" Type
  | TypeD "type" Con VarList "=" TyDecl
  | TypeD0 "type" Con VarList
  | AscribeD Var "::" Type
  | VarD Var DeclSym Exp
  | ProcD Var Exp0List DeclSym Exp
  | InstD "instance" Con Type

data DeclSym
  | Macro "=>"
  | Define "="

data ExtNm
  | SomeNm string
  | NoneNm 

group {

data Exp
  | BlockE "do" "{" Exp5List "}"
  | _ Exp5

data Exp5
  | LetS Exp4 DeclSym Exp -- sugar which can only appear in a block and lhs only var
  | LetE "let" Exp4 DeclSym Exp "in" Exp
  | LamE "\\" Exp0List "->" Exp
  | StoreE Exp4 "<-" Exp
  | CaseE "case" Exp "of" "{" CaseAltList DefaultAlt "}"
  | SwitchE "switch" Exp "of" "{" SwitchAltList DefaultAlt "}"
  | BranchE "branch" "{" BranchAltList "|" Exp ";" "}"
  | _ Exp4

data Exp4
  | BinOpE Exp3 usym Exp3
  | _ Exp3

data Exp3
  | AppE Exp3 Exp2
  | _ Exp2

data Exp2
  | UnOpE UnOp Exp1
  | _ Exp1

data Exp1
  | IdxE Exp1 "[" Exp "]"
  | FldE Exp1 "." Field
  | _ Exp0

data Exp0
  | ArrayE "Array" "[" ExpList "]"
  | RecordE "{" FieldDList "}"
  | TupleE "(" ExpList ")"
  | AscribeE "(" Exp "::" Type ")"
  | CountE Count
  | VarE Var
  | LitE Lit

}

data UnOp | Load "@"

data CaseAlt | CaseAlt Con VarList "->" Exp

data SwitchAlt | SwitchAlt Lit "->" Exp

data DefaultAlt
  | DefaultAlt Var "->" Exp ";"
  | DefaultNone

data BranchAlt | BranchAlt Exp4 "->" Exp

data Cxt | Cxt Con VarList

group {

data Type
  | TyCxt "{" CxtList "}" "=>" Type3
  | _ Type3

data Type3
  | TyFun Type2 "->" Type3
  | _ Type2

data Type2
  | TyArray "Array" Type1 Type1
  | TyConstr Con Type1List
  | _ Type1

data Type1
  | _ Type0

data Type0
  | TyTuple "(" TypeList ")"
  | TyCount Count
  | TyVarT TyVar
  | TyConstr0 Con

}

data TyDecl
  | TyRecord "{" FieldTList "}"
  | TyTagged "|" ConCList
  | TySyn Type

data ConC | ConC Con Type0List

data FieldT | FieldT Field "::" Type

data Lit
  | CharL char
  | StringL string
  | NmbrL number
  | EnumL Con

data FieldD | FieldD Field "=" Exp

data Count | Count "#" "" number

data Var | Var lident

data Con | Con uident

data Modid | Modid uident

data Field | Field lident

data TyVar
 | VarTV lident
 | CntTV "#" lident

list BranchAltList BranchAlt empty terminator ";" vert
list CaseAltList CaseAlt empty terminator ";" vert
list SwitchAltList SwitchAlt empty terminator ";" vert
list TopDeclList TopDecl empty terminator ";" vert
list ImportList Import nonempty terminator ";" vert
list Exp5List Exp5 nonempty terminator ";" vert
list ExportList Export nonempty terminator ";" vert
list ConCList ConC nonempty separator "|" horiz
list Exp0List Exp0 nonempty separator "" horiz
list VarList Var empty separator "" horiz
list ExpList Exp empty separator "," horiz
list FieldDList FieldD nonempty separator "," horiz
list FieldTList FieldT nonempty separator "," horiz
list Type0List Type0 empty separator "" horiz
list Type1List Type1 nonempty separator "" horiz
list TypeList Type3 empty separator "," horiz
list CxtList Cxt nonempty separator "," horiz