You may be able to do this very easily with the range operator. 
while (<MYFILE>) {

    if (/^FH$/ .. /^FT$/) {

        # $_ is a line within FH and FT lines
        # including the delimiting lines

    }

    if (/^BH$/ ... /^BH$|^FT$/) {

        # $_ is a line between BH lines, or between
        # a BH and FT line

    }

[download]
Basically, the first if is true only if we've already found a line containing only FH, but haven't yet found a line containing FT. The second if is true when we've found a BH line, but haven't yet found either another BH line or an FT line.

Hope this helps,
-- Bird

Oh, the reason the second if uses three dots (...) is because the two dot version can become false in the same check that it became true. Essentially, if you use the two dot version to match a block which uses the same start and end delimiter, you may only end up processing the first line of the block (which would be the delimiter, in this case).

In reply to Re: Parse File With Sub While Loops by Bird
in thread Parse File With Sub While Loops by Anonymous Monk

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