On Fri, 8 Jun 2018 13:38:47 -0700 (PDT) John Hardin wrote: > On Fri, 8 Jun 2018, Alex wrote: > > > Is a plugin necessary to tag on when the Subject matches content in > > the From? > > No, you can do a header rule that matches multiple headers that way. > The problem is there's no guarantee the order the headers appear, so > it would require multiple rules or have incomplete coverage if it's > not possible to express it correctly in both directions.
It can be done if you capture inside a lookahead. For example: body X_EQUALS_Y /^(?=.*X=(\d+)\b).*Y=\1\b/ will match on the strings 'let X=9 and Y=9' or 'let Y=9 and X=9' but not on 'let X=4 and Y=9'
