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</o:shapelayout></xml><![endif]--></head><body lang=DE-CH link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><font size=2 face=Calibri><span lang=EN-US style='font-size:11.0pt;mso-fareast-language:EN-US'>Did somebody contact NW already?<o:p></o:p></span></font></p><p class=MsoNormal><font size=2 face=Calibri><span lang=EN-US style='font-size:11.0pt;mso-fareast-language:EN-US'>Jörg<o:p></o:p></span></font></p><p class=MsoNormal><font size=2 face=Calibri><span lang=EN-US style='font-size:11.0pt;mso-fareast-language:EN-US'><o:p> </o:p></span></font></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><font size=2 face=Calibri><span lang=EN-US style='font-size:11.0pt;font-weight:bold'>From:</span></font></b><span lang=EN-US> Oberon [mailto:oberon-bounces@lists.inf.ethz.ch] <b><span style='font-weight:bold'>On Behalf Of </span></b>Andreas Pirklbauer<br><b><span style='font-weight:bold'>Sent:</span></b> Thursday, October 12, 2017 3:16 PM<br><b><span style='font-weight:bold'>To:</span></b> ETH Oberon and related systems <oberon@lists.inf.ethz.ch><br><b><span style='font-weight:bold'>Subject:</span></b> [Oberon] Clarifying type compatibility in Oberon-07<o:p></o:p></span></p></div></div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>See the 2 inline comments below:</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'><br><br></span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>></span></font><o:p> </o:p></p><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> * MODULE M; (*test of the implementation of Oberon-07 as of 12.10.17*) > * VAR > * p, q: ARRAY 10 OF INTEGER; > * r, s: ARRAY 10 OF INTEGER; > * e, f: PROCEDURE (i, j: INTEGER); > * g, h: PROCEDURE (i, j: INTEGER); > * a, b: RECORD i, j: INTEGER END ; > * c, d: RECORD i, j: INTEGER END ; </span></font><o:p></o:p></p></div><div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'><br><br></span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> * p := r; (*ok -> structural equivalence suffices*) </span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>></span></font><o:p> </o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> Acc 9.1 only allowed for open array. So, I see this as compiler bug. A hint why</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> it is a compiler bug: If the structural equivalence was included in SAME, exception</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> 4 mentioned in 9.1 would not be needed. So, it is in my view wrong to include</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> structural equivalence in SAME.</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'><br><br></span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>I just stated that structural equivalence for arrays *is* currently implemented (see</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>ORP.CompTypes) and also that the current language report does *not* actually make it</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>clear whether it *should* be in the language or not. Whether it *should* be “in”</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>or “out” is a separate question. There are of course the two options:</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'> 1. It is viewed as a compiler bug -> then one should simply remove it</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'> 2. It is not viewer as a bug -> then one should remove exception 4 in 9.1.</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>But either way, the language report should be updated such that there is no ambiguity.</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> * e := g; (*ok -> structural equivalence suffices*)</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>></span></font><o:p> </o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> My interpretation of section 6.5: only allowed it for (const) P.</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>> A “g” is a variable, I would not allow. </span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>Same response here. At the very least, the language report needs to be made</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>clearer. Currently it states: "If a procedure P is assigned to a procedure</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>variable of type T”. To most people (including you) the word “a procedure P”</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>means "procedures declared the usual way” but excludes procedure *variables*.</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>=></span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>I think we really have exhausted this topic and are scraping the bottom. All</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>arguments are on the table, with different points of views for the pros and cons.</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>But we all (seem to) agree that the language report needs revision in that</span></font><o:p></o:p></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>it should a) leave no ambiguity and b) be in line with the implementation.</span></font><o:p></o:p></p></div></div><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div><div><p class=MsoNormal><font size=2 face="Courier New"><span style='font-size:11.0pt;font-family:"Courier New"'>-AP</span></font><o:p></o:p></p><div><p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt'><o:p> </o:p></span></font></p></div></div></div></div></div></body></html>