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Module Ast

module Ast: sig .. end

Abstract Syntax of Mini Java

Parsed trees

This is the output of the parser and the input of the type checker.

type location = Stdlib.Lexing.position * Stdlib.Lexing.position 
type ident = {
   loc : location;
   id : string;
} 
type unop =
| Uneg (*

-e

*)
| Unot (*

!e

*)
| Ustring_of_int (*

integer to string conversion, introduced during type checking

*) 
type binop =
| Badd
| Bsub
| Bmul
| Bdiv
| Bmod (*

+ - * / %

*)
| Beq
| Bneq
| Blt
| Ble
| Bgt
| Bge (*

== != < <= > >=

*)
| Band
| Bor (*

&& ||

*)
| Badd_s (*

string concatenation, introduced during type checking

*) 
type constant =
| Cbool of bool
| Cint of int32
| Cstring of string 
type pexpr_typ =
| PTboolean
| PTint
| PTident of ident 
type pexpr = {
   pexpr_desc : pexpr_desc;
   pexpr_loc : location;
} 
type pexpr_desc =
| PEconstant of constant
| PEbinop of binop * pexpr * pexpr
| PEunop of unop * pexpr
| PEthis
| PEnull
| PEident of ident
| PEdot of pexpr * ident
| PEassign_ident of ident * pexpr
| PEassign_dot of pexpr * ident * pexpr
| PEnew of ident * pexpr list
| PEcall of pexpr * ident * pexpr list
| PEcast of pexpr_typ * pexpr
| PEinstanceof of pexpr * pexpr_typ 
type pstmt = {
   pstmt_desc : pstmt_desc;
   pstmt_loc : location;
} 
type pstmt_desc =
| PSexpr of pexpr
| PSvar of pexpr_typ * ident * pexpr option
| PSif of pexpr * pstmt * pstmt
| PSreturn of pexpr option
| PSblock of pstmt list
| PSfor of pstmt * pexpr * pstmt * pstmt 
type pparam = pexpr_typ * ident 
type pdecl =
| PDattribute of pexpr_typ * ident
| PDconstructor of ident * pparam list * pstmt
| PDmethod of pexpr_typ option * ident * pparam list * pstmt 
type pclass = ident * ident option * pdecl list 
type pfile = pclass list

Typed trees

This is the output of the type checker and the input of the code generation.

type typ =
| Tvoid
| Tnull
| Tboolean
| Tint
| Tclass of class_ 
type class_ = {
   class_name : string;
   mutable class_extends : class_;
   class_methods : (string, method_) Stdlib.Hashtbl.t;
   class_attributes : (string, attribute) Stdlib.Hashtbl.t;
} 
type attribute = {
   attr_name : string;
   attr_type : typ;
   mutable attr_ofs : int; (*

position within the object

*)
}

All the occurrences of the same attribute point to a single record of the following type.

type method_ = {
   meth_name : string; (*

unique name

*)
   meth_type : typ;
   meth_params : var list;
   mutable meth_ofs : int; (*

position within the method table

*)
} 
type var = {
   var_name : string;
   var_type : typ;
   mutable var_ofs : int; (*

position wrt %rbp

*)
}

All the occurrences of the same variable point to a single record of the following type.

type expr = {
   expr_desc : expr_desc;
   expr_type : typ;
} 
type expr_desc =
| Econstant of constant
| Ebinop of binop * expr * expr
| Eunop of unop * expr
| Ethis
| Enull
| Evar of var
| Eassign_var of var * expr
| Eattr of expr * attribute
| Eassign_attr of expr * attribute * expr
| Enew of class_ * expr list
| Ecall of expr * method_ * expr list
| Ecast of class_ * expr
| Einstanceof of expr * string
| Eprint of expr 
type stmt =
| Sexpr of expr
| Svar of var * expr
| Sif of expr * stmt * stmt
| Sreturn of expr option
| Sblock of stmt list
| Sfor of stmt * expr * stmt * stmt 
type decl =
| Dconstructor of var list * stmt
| Dmethod of method_ * stmt 
type tclass = class_ * decl list 
type tfile = tclass list