Entries rules can be deleted using the function
``Grammar.delete_rule''. But, like for
``Grammar.extend'', it is not documented. One must use the
instruction ``DELETE_RULE'', generating a call to this
function. This instruction is a syntax extension, loaded together with
the instruction ``EXTEND'' by the file
``pa_extend.cmo''.
The syntax of ``DELETE_RULE'' is:
DELETE_RULE |
| entry : symbol ; ... symbol |
END |
The rule defined by the list of symbols (semantic actions forgotten), if found, is deleted.