..      The range operator, which is  really  two  different
             operators  depending  on  the  context.  In an array
             context, returns an array  of  values  counting  (by
             ones)  from the left value to the right value.  This
             is useful for writing "for (1..10)"  loops  and  for
             doing slice operations on arrays.

             In a scalar context, ..  returns  a  boolean  value.
             The  operator  is bistable, like a flip-flop..  Each
             .. operator maintains its own boolean state.  It  is
             false  as  long  as its left operand is false.  Once
             the left operand is true, the range  operator  stays
             true  until  the  right operand is true, AFTER which
             the range operator becomes false again.  (It doesn't
             become  false  till the next time the range operator
             is evaluated.  It  can  become  false  on  the  same
             evaluation it became true, but it still returns true
             once.)  The right operand is not evaluated while the
             operator  is  in  the  "false"  state,  and the left
             operand is not evaluated while the  operator  is  in
             the  "true"  state.   The scalar .. operator is pri-
             marily intended for doing line number  ranges  after
             the fashion of sed or awk.  The precedence is a lit-
             tle lower than || and &&.   The  value  returned  is
             either  the  null  string  for  false, or a sequence
             number (beginning with 1) for  true.   The  sequence
             number  is  reset  for  each range encountered.  The
             final sequence number in a range has the string 'E0'
             appended  to  it,  which  doesn't affect its numeric
             value, but gives you something to search for if  you
             want  to  exclude the endpoint.  You can exclude the
             beginning point by waiting for the  sequence  number
             to  be  greater than 1.  If either operand of scalar
             .. is static, that operand is implicitly compared to
             the $. variable, the current line number.  Examples:

             As a scalar operator:
                 if (101 .. 200) { print; }       # print 2nd hundred lines

                 next line if (1 .. /^$/);       # skip header lines

                 s/^/> / if (/^$/ .. eof());    # quote body

             As an array operator:
                 for (101 .. 200) { print; }      # print $_ 100 times

                 @foo = @foo[$[ .. $#foo]; # an expensive no-op
                 @foo = @foo[$#foo-4 .. $#foo]; # slice last 5 items