module Absyn = struct
  type expr = {
    kind: expr_kind;
    tags: aug_tag list;
  }

  and stmt = {
    kind: stmt_kind;
    tags: aug_tag list;
  }

  and expr_kind =
    | Primary of primary_factor
    | Unary of { factor: primary_factor; op: unary_op; }
    | Subscript of { factor: primary_factor; op: subscript_op; }
    | Binary of { left_factor: expr; right_factor: expr; op: binary_op; }
    | Ternary of { cond: expr; if_true: expr; if_false: expr; }
    | Assignment of { lvalue: expr; rvalue: expr; op: assign_op; }
    | StmtExpr of stmt

  and stmt_kind =
    | Expr of expr option
    | VarDecl of { attr: var_attr option; storage: storage_cls; tydecl: type_decl; declarators: declarator list option; }
    | For of { init: stmt option; cond: expr list option; iter: stmt option; body: stmt; }
    | DoWhile of { body: stmt; cond: expr; }
    | While of { cond: expr; body: stmt; }
    | If of { if_clause: if_clause; elsif_clauses: if_clause list option; else_clause: stmt option; }
    | Switch of { main_discrim: const_expr; case_clauses: (const_expr * stmt) list; default_clause: stmt option; }
    | InlineAsm of { asm: string; inputs: asm_cons list option; outputs: asm_cons list option; clobbers: string list option; }
    | NestedFunc of { proto: func_proto; name: string; body: stmt; }
    | ControlFlow of control_flow_stmt
    | Compound of compound_stmt
    | Labeled of label * stmt list


  and literal =
      ConstLiteral of const_lit | CompoundLiteral of compound_lit

  and const_lit =
    | IntConst of int * int_suffix option
    | FloatConst of float * float_suffix option
    | CharConst of char * charset_prefix option
    | StrConst of string * charset_prefix option
    | EnumConst of enum_const

  and int_suffix =
      Long | LongLong | Unsigned | UnsignedLong | UnsignedLongLong

  and float_suffix =
      Double | LongDouble

  and charset_prefix =
      Local | U8 | U16 | U32

  and compound_lit =
    | ArrayCompound of init_type * init_item list
    | StructCompound of init_type * init_item list
    | UnionCompound of init_type * init_item list

  and init_item =
    | RegularInit of expr
    | DesignatedInit of designated_init * expr

  and designated_init =
    | ConstExpr of const_expr
    | Ident of string

  and init_type = type_decl

  and enum_const =
    { name: string; value: const_expr option; }


  and const_expr =
    | ConstFactor of literal
    | ConstRange of const_expr * const_expr
    | UnaryConstExpr of { factor: literal; op: unary_op; }
    | BinaryConstExpr of { left_factor: literal; right_factor: literal; op: binary_op; }


  and primary_factor =
      Identifier of string | NestedExpr of expr | Literal of literal


  and prefix_unary_op =
    | Negate
    | LogicalNegate
    | BitwiseNot
    | AddressOf
    | AddressOfLabel
    | Dereference
    | PreIncrement
    | PreDecrement
    | Sizeof
    | Typeof

  and postfix_unary_op =
    | PostIncrement
    | PostDecrement

  and unary_op =
    | PrefixOp of prefix_unary_op
    | PostfixOp of postfix_unary_op

  and subscript_op =
    | Index of expr
    | DotMember of expr
    | ArrowMember of expr
    | FunctionCall of expr list

  and binary_op =
    | Add
    | Subtract
    | Multiply
    | Divide
    | Modulo
    | BitwiseAnd
    | Bitwise7Or
    | BitwiseXor
    | ShiftLeft
    | ShiftRight
    | LogicalAnd
    | LogicalOr
    | Equal
    | NotEqual
    | LessThan
    | LessThanOrEqual
    | GreaterThan
    | GreaterThanOrEqual

  and assign_op =
    | Assignment
    | AddAssign
    | SubtractAssign
    | MultiplyAssign
    | DivideAssign
    | ModuloAssign
    | AndAssign
    | OrAssign
    | XorAssign
    | ShiftLeftAssign
    | ShiftRightAssign


  and type_decl =
    { attr: type_attr option; qual: type_qual list; value: type_value; }

  and type_qual =
      Const | Volatile

  and type_value =
    | IntegeralType of type_int
    | AtomicType of type_int
    | RationalType of type_float
    | PointerType of type_pointer
    | ArrayType of type_array
    | EnumType of type_enum
    | StructType of type_struct
    | UnionType of type_union
    | FuncType of type_func
    | ComplexType of type_complex
    | VoidType

  and type_int =
    { signage: int_signage option; word: int_word; }

  and int_word =
    | Char
    | Short
    | Int
    | Long
    | LongLong
    | UChar
    | UShort
    | UInt
    | ULong
    | ULongLong

  and int_signage =
      Signed | Unsgiend

  and type_float =
    | Float
    | Double
    | LongDouble

  and type_pointer =
    { base: type_decl; depth: int; qual: pointer_qual; }

  and pointer_qual =
      Const | Volatile | Restrict

  and type_array = {
    arr_type: type_decl;
    arr_size: int option;
  }

  and type_struct = {
    struct_tag: string option;
    struct_fields: field_item list;
  }

  and type_union = {
    union_name: string option;
    union_fields: field_item list;
  }

  and field_item = {
    name: string;
    typ: type_decl;
  }

  and type_enum = {
    enum_name: string option;
    enum_values: enum_const list;
  }

  and type_complex =
    | ComplexFloat
    | ComplexDouble
    | ComplexLongDouble

  and type_func = {
    func_return_type: type_decl;
    func_params: (string option * type_decl) list;
    func_is_variadic: bool;
  }

  and storage_cls =
      Extern | Auto | Register | Static

  and declarator =
    | Assigned of expr * expr
    | Unassigned of expr

  and if_clause =
    { cond: expr; body: stmt; }

  and asm_cons =
    { reg: string; value: expr option; }

  and control_flow_stmt =
    | Continue
    | Break
    | Goto of label
    | Return of expr option

  and label = string

  and compound_stmt = stmt list


  and toplvl_stmt =
    | TypeDef of { tydecl: type_decl; alias: expr; }
    | FuncDef of {  proto: func_proto; name: string; body: stmt; }
    | GlobDecl of toplvl_decl


  and toplvl_storage =
      Extern | Auto | Static

  and func_proto =
    { attr: func_attr option; typ: type_func; storage: toplvl_storage; inline: bool; }

  and toplvl_decl =
    | FunDecl of func_proto
    | StructDecl of type_struct
    | UnionDecl of type_union
    | EnumDecl of type_union


  and trans_unit = toplvl_stmt list


  and func_attr =
    | Noreturn
    | Format of string * int * int
    | Pure
    | Const
    | Deprecated
    | Used
    | Unused
    | Weak
    | Alias of string
    | Visibility of string
    | No_instrument_function
    | Constructor
    | Destructor
    | Nonnull of int list
    | Malloc
    | Section of string
    | Nothrow
    | Always_inline
    | Noinline


  and var_attr =
    | Deprecated
    | Unused
    | Weak
    | Aligned of int option
    | Packed
    | Section of string
    | Used
    | Cleanup of string
    | Transparent_union


  and type_attr =
    | Packed
    | Aligned of int option
    | Deprecated

  and aug_tag =
    | TypeTag of type_info
    | CategoryTag of value_category_info
    | ControlFlowTag of control_flow_info
    | DataFlowTag of data_flow_info
    | SSATag of ssa_info
    | RegAllocTag of reg_alloc_info
    | LocationTag of location_info
    | OptimizationInfo of optimization_info
    | DiagnosticTag of diagnostic_info
    | DependencyTag of dependency_info
    | MemoryAccessTag of memory_access_info
    | InterproceduralInfo of interprocedural_info
    | ScopeTag of scope_info
    | LinkageTag of linkage_info

  and value_category_info =
    | LocatorVal
    | ReadVal

  and type_info = {
    mutable_type: bool;
    type_size: int;
    type_align: int;
  }

  and control_flow_info = {
    entering_blocks: string list;
    exiting_blocks: string list;
  }

  and data_flow_info = {
    defs: (string * location_info) list;
    uses: (string * location_info) list;
    live_in: string list;
    live_out: string list;
  }

  and ssa_info = {
    version: int option;
  }

  and reg_alloc_info = {
    assigned_register: string option;
  }

  and location_info = {
    file: input_source;
    line_no: int;
    line_token_no: int;
    line_char_no: int;
    total_token_no: int;
    total_char_no: int;
  }

  and input_source = STDIN | File of string

  and optimization_info = {
    loop_unrolling_factor: int option;
    should_inline: bool;
    vectorization_hint: bool;
  }


  and diagnostic_info = {
    severity: diagnostic_severity;
    message: string;
    suggestion: string option;
  }

  and diagnostic_severity = Error | Warning | Info

  and dependency_info = {
    depends_on: string list;
    used_by: string list;
  }


  and memory_access_info = {
    access_pattern: memory_access_pattern;
    stride: int option;
  }

  and memory_access_pattern = Sequential | Random | Strided

  and interprocedural_info = {
    call_graph_node: string list;
    has_side_effects: bool;
  }

  and scope_info = {
    level: scope_level;
    defined_in: scope_level;
  }

  and scope_level =
    | GlobalScope
    | FunctionScope of string
    | BlockScope of string

  and linkage_info =
    | External
    | Internal


end