%token ID ARROW LPAREN RPAREN COLON SEMICOLON
%start<unit> program
%on_error_reduce typ1
%%
typ0: ID | LPAREN typ1 RPAREN {}
typ1: typ0 | typ0 ARROW typ1  {}
declaration: ID COLON typ1    {}
program:
| LPAREN declaration RPAREN
| declaration SEMICOLON       {}
