<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta content="text/html;charset=UTF-8" http-equiv="Content-Type"></head><body ><div style='font-size:10pt;font-family:Verdana,Arial,Helvetica,sans-serif;'>Part 4 of the Blue Book--chapter 26 The implementation--in the intro there is this example:<br><br><br><br><blockquote style="border: 1px solid rgb(204, 204, 204); padding: 7px; background-color: rgb(245, 245, 245);"><div>center<br> ^ origin + corner / 2<br></div></blockquote> <br><br>With these operations<br><br><blockquote style="border: 1px solid rgb(204, 204, 204); padding: 7px; background-color: rgb(245, 245, 245);"><div><br>Rectangle center<br> 0 push the value of the receiver's first instance variable (origin) onto the<br> stack<br> 1 push the value of the receiver's second instance variable (corner) onto the<br> stack<br> 176 send a binary message with the selector +<br> 119 push the Smalllnteger 2 onto the stack<br> 185 send a binary message with the selector /<br> 124 return the object on top of the stack as the value of the message (center)<br></div></blockquote> <br>In a Workspace, when I doit on 3 + 7/2 I get 5, left, right, unary, binary....rules apply.<br><br>What I see here--and please check my reasoning--is a RPN that places things onto the stack via Smalltalk's order of operation rules and then does conventional RPN processing.<br><br>In other words, Smalltalk expressions are translated to RPN and then placed on the stack.<br><br>A simple 'banish the thought' or 'yep' or 'sometimes' would be helpful as I move forward in my study. I am just trying to avoid carrying forward an improper idea that I will have to revise later when/if the facts turn out otherwise.<br><br>thx.<br><br>t<br></div></body></html>