RePar

%{
  (* File Expr/ExprPar.fsy
     Parser specification for the simple expression language.
   *)

  open Absyn
%}

%token LPAR RPAR
%token <char> RE
%token STAR
%token PIPE
%token EOF

%start Main
%type <Absyn.re> Main

%right LPAR
%left RPAR
%right PIPE
%left STAR

%%

Main:
    Re EOF                          { $1                }
;

Re:
    LPAR Re RPAR                      { $2                }
  | Re STAR                           { Star ($1)         }
  | Concat                            { $1                }
  | Union                             { $1                }
  | RE                                { Char ($1)         }
;

Concat:
    Re Re                             { Seq ($1, $2)      }
;

Union:
    Re PIPE Re                        { Choice ($1, $3)   }
;

// vim: set ts=4 sw=4 et: