lvarpop var ?indexExpr? ?string?
          The lvarpop command pops (deletes) the element indexed by the
          expression indexExpr from the list contained in the variable
          var. If index is omitted, then 0 is assumed. If string is
          specified, then the deleted element is replaced by string. The
          replaced or deleted element is returned. Thus 

          lvarpop argv 0

          returns the first element of argv, setting argv to contain
          the remainder of the string.

          If the expression indexExpr starts with the string "end", then
          end is replaced with the index of the last element in the
          list. If the expression starts with "len", then len is replaced
          with the length of the list.


See also [lvarpush].




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[Category Command], a part of [Tclx]