.. keyword:: while
  while (expr) statement;

  While 'expr' evaluates to non 0, execute statement.

  A :keyword:`break` in the 'statement' will terminate the loop. A :keyword:`continue` will continue the execution from the beginning of the loop.

  .. seealso:: :keyword:`for`, :keyword:`foreach`, :keyword:`do-while`, :keyword:`if`, :keyword:`switch`