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Add : Mult /[+-]/ Add
    | Mult

Add : Mult ( /[+-]/ Add )*

<rule: Add>
    <[X=Mult]> ** <[Op=(\+|-)]>

<rule: Equal>
    <X=Term> <Op=(==|!=|\x3c=\x3e|eq|ne|cmp)> <Y=Term>
    | <MATCH=LessGreater>

Equal : Term OP Term
      | LessGreater

Equal : LessGreater OP LessGreater
      | LessGreater

Equal : LessGreater (?: OP LessGreater )?

<rule: Equal>
    <X=LessGreater> (?: <Op=(==|!=|\x3c=\x3e|eq|ne|cmp)> <Y=LessGreate
+r> )?

<rule: Equal>
    <X=LessGreater>
...
    |
        (?{ ... }
    )

#!perl
use v5.10;
...
        say 'PARSE FAILURE';
    }
}