<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "> <br><div><div>On Feb 17, 2009, at 6:20 AM, James Coglan wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; ">... in the Scheme spec it says that operands are to be evaluated in an unspecified order.<span class="Apple-converted-space"> ...</span></span></blockquote><br></div><div>Here is the meaning of this statement. Say you have an application with several subexpressions </div><div><br></div><div> (M n K)</div><div><br></div><div>and at least two of them are NOT values yet, say, M and K. Then the compiler can arrange two different sequences </div><div><br></div><div> evaluate M, store away value m</div><div> evaluate K, store away value k</div><div> test that m is a function and then call m{n,k}</div><div><br></div><div>OR </div><div><br></div><div> evaluate K, store away value k</div><div> evaluate M, store away value m</div><div> test that m is a function and then call m{n,k}</div><div><br></div><div>Now take a look at your program and check whether it contains such an application. NB, application includes such things as (+ 1 2). </div><div><br></div><div><br></div><div>-- Matthias</div><div><br></div><div><br></div><br></body></html>