##C, C++, Pascal, and many other imperative languages have a form of a
##loop with the loop test at the bottom, or (equivalently) a loop which is
##always executed at least once. Here is how it would be used in C:
##
##    /* Skip past the header */
##    do {
##        line = file.readOneLine();
##    } while isHeaderLine( line );
##
##Notice that if we were to translate this into a while loop (test-at-top
##loop) then the data preparation step would have to be repeated:
##
##    /* Skip past the header */
##    line = file.readOneLine();
##    while( isHeaderLine(line) ) {
##        line = file.readOneLine();
##    }
##
##Repeating it is bad style, and it gets quite bad if there's more than a
##single line (exception handling, for instance). So what is a programmer
##to do in Python, which has only the test-at-top style of loops? Here it is:
##
##    # Skip past the header
##    while 1:
##        line = file.readOneLine();
##        if not isHeaderLine( line ): break