Re: xor condition
On 07/16/2011 08:59 PM, Matt Benson wrote: xor(true, false) == true xor(true, false, true) == false xor(true, false, true, false) == false Is this correct? Follows the usual semantics; cf.: http://en.wikipedia.org/wiki/Exclusive_or#Associativity_and_commutativity It would seem that semantically an xor over multiple nested conditions should mean that exactly one value should evaluate true in order for the xor operation to yield truth. Which is in fact the case in the examples you mentioned, but probably you are thinking of xor(true, true, true) == true which is consistent with the algebraic definition, and the behavior of Java's ^ operator for that matter. If you wanted a condition with the semantics you describe, it should be named something else. - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org
Re: xor condition
On Wed, Jul 20, 2011 at 5:44 AM, Jesse Glick jesse.gl...@oracle.com wrote: On 07/16/2011 08:59 PM, Matt Benson wrote: xor(true, false) == true xor(true, false, true) == false xor(true, false, true, false) == false Is this correct? Follows the usual semantics; cf.: http://en.wikipedia.org/wiki/Exclusive_or#Associativity_and_commutativity It would seem that semantically an xor over multiple nested conditions should mean that exactly one value should evaluate true in order for the xor operation to yield truth. Which is in fact the case in the examples you mentioned, but probably you are thinking of xor(true, true, true) == true which is consistent with the algebraic definition, and the behavior of Java's ^ operator for that matter. If you wanted a condition with the semantics you describe, it should be named something else. Thanks, Jesse--I think you cleared it up in my head: and(x, y, z) = x y z or(x, y, z) = x | y | z xor(x, y, z) = x ^ y ^ z Thanks! Matt - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org
xor condition
Currently each nested condition is xor'd against the cumulative result, thus: xor(true, false) == true xor(true, false, true) == false xor(true, false, true, false) == false Is this correct? It would seem that semantically an xor over multiple nested conditions should mean that exactly one value should evaluate true in order for the xor operation to yield truth. Matt - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org
Re: xor condition
On 2011-07-17, Matt Benson wrote: Currently each nested condition is xor'd against the cumulative result, thus: xor(true, false) == true xor(true, false, true) == false xor(true, false, true, false) == false Is this correct? It would seem that semantically an xor over multiple nested conditions should mean that exactly one value should evaluate true in order for the xor operation to yield truth. While my gut feeling agrees with what you describe the documentation of the xor description actually says , | It only evaluates to true if an odd number of nested conditions are true. ` If you need the other kind of xor then a new container would be required. exactlyOneOf or something similar? Stefan - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org
Re: xor condition
On Sat, Jul 16, 2011 at 10:21 PM, Stefan Bodewig bode...@apache.org wrote: On 2011-07-17, Matt Benson wrote: Currently each nested condition is xor'd against the cumulative result, thus: xor(true, false) == true xor(true, false, true) == false xor(true, false, true, false) == false Is this correct? It would seem that semantically an xor over multiple nested conditions should mean that exactly one value should evaluate true in order for the xor operation to yield truth. While my gut feeling agrees with what you describe the documentation of the xor description actually says , | It only evaluates to true if an odd number of nested conditions are true. ` So is this an accepted kind of xor? If you need the other kind of xor then a new container would be required. exactlyOneOf or something similar? I don't need it, personally, yet. Was working in Commons Lang, noticed the discrepancy between oacl.BooleanUtils.xor() and Ant's xor condition, and wanted to follow up. br, Matt Stefan - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org
Re: xor condition
On 2011-07-17, Matt Benson wrote: , | It only evaluates to true if an odd number of nested conditions are true. ` So is this an accepted kind of xor? Accepted by the original author (Steve IIRC), silently accepted by all reviewers back then and in a way accepted as that's what it does by Ant's users, I guess 8-) Stefan - To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org For additional commands, e-mail: dev-h...@ant.apache.org
