<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Dec 11, 2007, at Dec 11:11:11 PM, Terry Reedy wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">"Steven D'Aprano" <<a href="mailto:steve@REMOVE-THIS-cybersource.com.au">steve@REMOVE-THIS-cybersource.com.au</a>> wrote in message<span class="Apple-converted-space"> </span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><a href="news:13lts6gb9t2j350@corp.supernews.com">news:13lts6gb9t2j350@corp.supernews.com</a>...</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">||</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">| But loops that run at least once is a basic element of algorithms.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">| Perhaps not as common as the zero or more times of the while loop, but</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">| still fundamental. It is a shame it has to be faked using:</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">|</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">| while True: # force the first iteration to always run</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">|<span class="Apple-converted-space"> </span>process</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">|<span class="Apple-converted-space"> </span>if condition: break</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">|</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">| Ugly and misleading.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">I disagree.<span class="Apple-converted-space"> </span>Nothing is being faked.<span class="Apple-converted-space"> </span>The generic loop is</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">while True:</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span class="Apple-converted-space"> </span>pre_process</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span class="Apple-converted-space"> </span>if condition: break</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span class="Apple-converted-space"> </span>post_process</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div></blockquote><div><br class="webkit-block-placeholder"></div><div>I find that when teaching beginning programmers, they usually think in "until" terms, and not "while" terms.</div><div><br class="webkit-block-placeholder"></div><div>do:</div><div> Forward()</div><div>until Touched()</div><div><br class="webkit-block-placeholder"></div><div>and I have to explain to them that Python doesn't have "until", and that the logic for while is exactly the opposite:</div><div><br class="webkit-block-placeholder"></div><div>while not Touched():</div><div> Forward()</div><div><br class="webkit-block-placeholder"></div><div>they find the "while" logic to be unintuitive, and I often find myself feeling the same way: crafting it with the until logic, and then reversing it. Perhaps I should do as above, and do:</div><div><br class="webkit-block-placeholder"></div><div>while True:</div><div> Forward()</div><div> if Touched(): break</div><div><br></div><div>but somehow that feels wrong to me, like bypassing the point of the while: all that power to check for conditions, and you just use it to check True, and then use a break inside. It's readable, I guess, but not a programming construct I am immediately drawn to.</div><div><br class="webkit-block-placeholder"></div><div><br class="webkit-block-placeholder"></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>Brian Blais<br class="webkit-block-placeholder"></div><div><br class="webkit-block-placeholder"></div><div><br class="webkit-block-placeholder"></div></div><div><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Monaco; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>-- </div><div>Brian Blais</div><div><a href="mailto:bblais@bryant.edu">bblais@bryant.edu</a></div><div><a href="http://web.bryant.edu/~bblais">http://web.bryant.edu/~bblais</a></div><div><br class="khtml-block-placeholder"></div><br class="Apple-interchange-newline"></span> </div><br></body></html>