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--></style></head><body lang=DE-CH link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>Instead of this<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> CASE x OF<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> 0:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> | 2:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> | 10:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> ELSE<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> END;<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>you could write more explicitly:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> CASE x OF<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> 0:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> | 2:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> | 10:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> | 1, 3..9:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'> END;<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>br<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'>Jörg<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:12.0pt;color:black'>Von: </span></b><span style='font-size:12.0pt;color:black'>Oberon <oberon-bounces@lists.inf.ethz.ch> im Auftrag von Andreas Pirklbauer <andreas_pirklbauer@yahoo.com><br><b>Antworten an: </b>ETH Oberon and related systems <oberon@lists.inf.ethz.ch><br><b>Datum: </b>Freitag, 16. Februar 2018 um 11:14<br><b>An: </b>ETH Oberon and related systems <oberon@lists.inf.ethz.ch><br><b>Betreff: </b>[Oberon] CASE without ELSE<o:p></o:p></span></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><a name="_MailOriginalBody"><span style='font-family:"Courier New"'><br><br></span></a><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>> My interpretation of what might have happened is this: > In Oberon07 the numeric CASE had been dropped, but later</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>> it has been reintroduced but the ELSE has been forgotten.</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'><br><br></span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>That’s one possibility. Another possibility would be that</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>it was dropped but the grammar was not fully restricted</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>to the non-numerical case, i.e. only the ELSE was removed</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>but not the fact that that case expression can an integer.</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'><br><br></span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>Either way, we now have a language spec that contains the</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>numerical case, but an implementation that doesn’t.</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>> To me, a numeric CASE without an ELSE is pointless.</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'><br><br></span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>Agreed. It was the absence of the ELSE clause and the fact</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>that the numeric case hadn’t been implemented in PO2013</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>for ~5 years now that caused me to believe that the</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>intended main use of the CASE statement is with records</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>and pointer types (i.e. to check extension levels),</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>where the ELSE clause is indeed not needed, since it</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>is implicit if the base type appears as the last case.</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'><br><br></span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>> My conclusion so far is: If the numeric CASE is not</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>> implemented but only specified, it should not be</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>> taken literally.</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'><br><br></span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'><span style='font-family:"Courier New"'>Extensions levels are (internally) also numbers of course ;-)</span></span><span style='mso-bookmark:_MailOriginalBody'><o:p></o:p></span></p></div><p class=MsoNormal><span style='mso-bookmark:_MailOriginalBody'>-- Oberon@lists.inf.ethz.ch mailing list for ETH Oberon and related systems https://lists.inf.ethz.ch/mailman/listinfo/oberon </span><o:p></o:p></p></div></body></html>