grammar.txt

<program> ::=
  [type_def]* <expr_seq> EOF

<types> ::=
  | int
  | bool
  | unit
  | REF <types>
  | T_VAR
  | T_VAR IDENT
  | IDENT
  | <types> -> <types>
  | ( <types> )

<types_def> ::=
  | type IDENT = { [[mutable]? IDENT : <types>;]+ }
  | type [T_VAR]? IDENT = [ | UIDENT [of [<types> *]* <types>]? ]

<expr_seq> ::=
  | <expr>
  | <expr> ; <expr_seq>

<expr> ::=
  | <s_expr>
  | <uop> <exprssion>
  | <expr> <binop> <expr>
  | <app_expr> <simple_expr>
  | REF <simple_expr>
  | IDENT := <expression>
  | if <expr_seq> then <expr>
  | if <expr_seq> then <expr> else <expr>
  | fun <fun_args> -> <expr_seq>
  | <s_expr>.IDENT <- <expr>
  | <s_expr>.(<expr_seq>) <- <expr>
  | let [rec]? IDENT [<let_ags>]* [:<types>] = <expr_seq> in <expr_seq>
  | MATCH <expression> WITH [pattern_expr]+
  | <print_type> <simple_expr>

<s_expr> ::=
  | n
  | true | false
  | ()
  | IDENT
  | ( expr_seq )
  | <s_expr>.IDENT
  | <s_expr>.(expr_seq)
  | { [ IDENT = <expr>; ]* }
  | [| [[ <s_expr>; ]* <s_expr>]? |]
  | Array.create <s_expr> <s_expr>
  | UIDENT [([<expr>, ]* <expr>)]?

<let_args> ::=
  | IDENT
  | ()
  | (IDENT: <types>)

<print_type> ::=
  | print_int
  | print_bool
  | print_char
  | print_string
  | print_endline
  | print_newline

<pattern> ::=
  | n 
  | id 
  | bool 
  | CONSTR 
  | CONSTR ( <pattern> [, <pattern>]* )

<pattern_expr> ::= 
  | | <pattern> -> expr_seq

<uop> ::=
  | -
  | not
  | !
  | Array.length | String.length

<binop> ::=
  | +   | -
  | mod
  | *   | / 
  | ==  | !=
  | =   | <>
  | <=  | <
  | ||  | &&