data Module
  | HModule "#ifndef" uident "\n#define" uident "\n" ImportList DeclareList "\n#endif"
  | CModule ImportList DefineList

data Import
  | Import "#include" string
  | GImport "#include" "<" "" lident "" ">"

data Declare
  | Declare FunDecl
  | Typedef "typedef" Decl

data Define
  | Define FunDecl "{" StmtList "}"

data FunDecl
  | FunFD Type lident "" "(" "" ArgDeclList "" ")"
  | RetFunFD Type "(" "*" lident "(" "" ArgDeclList "" ")" ")" "(" "" TypeList "" ")"

data Type
  | TyName uident
  | TyPtr Type "" "*"
  | TyFun Type "(" "" "*" "" ")" "(" "" TypeList "" ")"
  | TyArray Type "[" number "]"
  | TyEnum "enum" "{" EnumCList "}"
  | TyStruct "struct" "{" DeclList "}"
  | TyUnion "union" "{" DeclList "}"

data EnumC | EnumC uident

data Decl
  | Decl Type lident
  | FunD Type lident "" "(" "" TypeList "" ")"

data Exp
  | AllocaE "alloca" "(" "sizeof" "(" Type ")" ")"
  | VarE lident
  | LitE Lit
  | CastE "(" Type ")" Exp
  | LoadE "*" "" Exp
  | ArrowE Exp "" "->" "" Exp
  | DotE Exp "" "." "" Exp
  | AddrE "&" "" Exp
  | IdxE Exp "" "[" "" Exp "" "]"
  | CallE Exp "" "(" "" ExpList "" ")"
  | BinOpE "(" "" Exp usym Exp "" ")"
  | ParenE "(" Exp ")"
  | NotE "!" "" Exp

data Stmt
  | DeclS Decl
  | AssignS Exp "=" Exp
  | CallS Exp "" "(" "" ExpList "" ")"
  | SwitchS "switch" "(" Exp ")" "{" SwitchAltList "}"
  | BreakS "break"
  | IfS "if" "(" Exp ")" "{" StmtList "}" "else" "{" StmtList "}"
  | WhenS "if" "(" Exp ")" "{" StmtList "}"
  | WhileS "while" "(" Exp ")" "{" StmtList "}"
  | ReturnS "return" "" "(" "" Exp "" ")"
  | RetVoidS "return"
  | NoOpS
  | BlockS StmtList
  | IncS Exp "" "++"
  | DecS Exp "" "--"

data SwitchAlt
  | SwitchAlt "case" Lit "" ":" StmtList
  | DefaultAlt "default:" StmtList

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

list TypeList Type empty separator "," horiz
list ExpList Exp nonempty separator "," horiz
list EnumCList EnumC nonempty separator "," horiz
list DeclList Decl empty terminator ";" horiz
list ArgDeclList Decl empty separator "," horiz
list SwitchAltList SwitchAlt empty terminator "" vert
list StmtList Stmt empty terminator ";" vert
list DeclareList Declare empty terminator ";" vert
list DefineList Define empty terminator ";" vert
list ImportList Import empty terminator "" vert