From martin@nagmx1.nag.co.uk Wed Jun 28 15:46:33 2000 Received: from frisco.nag.co.uk (frisco.nag.co.uk [192.156.217.22]) by nagmx1.nag.co.uk (8.9.3/8.9.3) with SMTP id PAA14909 for ; Wed, 28 Jun 2000 15:46:32 +0100 (BST) From: Martin Dunstan Date: Wed, 28 Jun 2000 15:41:33 +0100 Message-Id: <200006281441.PAA09299@frisco.nag.co.uk> Received: by frisco.nag.co.uk (SMI-8.6) id PAA09299; Wed, 28 Jun 2000 15:41:33 +0100 To: ax-bugs@nag.co.uk@nagmx1.nag.co.uk Subject: fixbug By: XXX Fixed: bug1137.as --* From youssef@mailer.scri.fsu.edu Fri Jan 23 02:51:02 1998 --* Received: from nagmx1.nag.co.uk by red.nag.co.uk via SMTP (920330.SGI/920502.SGI) --* for /home/red5/axiom/support/recvbug id AA12794; Fri, 23 Jan 98 02:51:02 GMT --* Received: from mailer.scri.fsu.edu (mailer.scri.fsu.edu [144.174.112.142]) --* by nagmx1.nag.co.uk (8.8.4/8.8.4) with ESMTP --* id CAA02032 for ; Fri, 23 Jan 1998 02:53:20 GMT --* Received: from sp2-8.scri.fsu.edu (sp2-8.scri.fsu.edu [144.174.128.98]) by mailer.scri.fsu.edu (8.8.7/8.7.5) with SMTP id VAA03921; Thu, 22 Jan 1998 21:50:46 -0500 (EST) --* From: Saul Youssef --* Received: by sp2-8.scri.fsu.edu (5.67b) id AA21279; Thu, 22 Jan 1998 21:50:45 -0500 --* Date: Thu, 22 Jan 1998 21:50:45 -0500 --* Message-Id: <199801230250.AA21279@sp2-8.scri.fsu.edu> --* To: adk@mailer.scri.fsu.edu, ax-bugs@nag.co.uk, edwards@mailer.scri.fsu.edu, --* youssef@mailer.scri.fsu.edu --* Subject: [5] Union funny business --@ Bug Number: bug1137.as --@ Fixed by: XXX --@ Tested by: union0.as --@ Summary: no fix -- Command line: axiomxl -g interp -Fx file.as -- Version: 1.1.10c -- Original bug file name: bug0.as --+ -- --+ -- Peter: --+ -- --+ -- I don't think that the results I get with this program are --+ -- correct. I would have expected the compiler to complain that --+ -- = is not defined for unions, but it seems to produce results --+ -- anyway. --+ -- --+ -- Regards, --+ -- Saul Youssef --+ -- --+ #include "axllib" --+ #pile --+ --+ SI ==> SingleInteger --+ --+ import from SI --+ --+ U == Union(foointeger:SI, barinteger:SI) --+ --+ foo42:U := [foointeger == 42] --+ bar42:U := [barinteger == 42] --+ foo42also:U := [foointeger == 42] --+ --+ if foo42=bar42 then print << "foo42=bar42" << newline --+ else --+ print << "foo42 ~= bar42" << newline --+ --+ if foo42=foo42also then print << "foo42=foo42also" << newline --+ else --+ print << "foo42 ~=foo42_also" << newline -- -- Peter: -- -- I don't think that the results I get with this program are -- correct. I would have expected the compiler to complain that -- = is not defined for unions, but it seems to produce results -- anyway. -- -- Regards, -- Saul Youssef -- #include "axllib" #pile SI ==> SingleInteger import from SI U == Union(foointeger:SI, barinteger:SI) foo42:U := [foointeger == 42] bar42:U := [barinteger == 42] foo42also:U := [foointeger == 42] if foo42=bar42 then print << "foo42=bar42" << newline else print << "foo42 ~= bar42" << newline if foo42=foo42also then print << "foo42=foo42also" << newline else print << "foo42 ~=foo42_also" << newline --+ Union is extended in Axllib to satisfy BasicType. However, the equality --+ test simply checks to see if the two arguments refer to the same object --+ in memory rather than checking to see that they have the same value. --+ --+ Hence this program is actually behaving correctly.