Re: Re: bug with definitions?
- To: mathgroup at smc.vnet.net
- Subject: [mg40421] Re: [mg40400] Re: bug with definitions?
- From: Dr Bob <majort at cox-internet.com>
- Date: Sat, 5 Apr 2003 03:57:13 -0500 (EST)
- References: <b6gm2e$cf9$1@smc.vnet.net> <200304040621.BAA06066@smc.vnet.net>
- Reply-to: majort at cox-internet.com
- Sender: owner-wri-mathgroup at wolfram.com
It seems to me that using a pattern like _?z makes no sense (at all) if z will never evaluate to True, as in this case. As a result, those two rules for a can never result in an evaluation. Nothing can possibly match. Bobby On Fri, 4 Apr 2003 01:21:33 -0500 (EST), Jens-Peer Kuska <kuska at informatik.uni-leipzig.de> wrote: > Hi, > > but Mathematica must do something with the right hand side of > RuleDelayed[] otherwise > how become you rule a member of DownValues[] ?? > > Since Catch[] and Throw[] are non-local operations, > a Throw[] can not protected by the processing > of the right hand side. Just use > > Clear[a, z]; > Catch[ > z[x_Integer] := 2; > z[x_] := Throw[11]; > a[i_, iUp_?z] := 3; > a[i_Integer, iUp_?z] := 5; > ] > > > Regards > Jens > > Hein H wrote: >> >> Why does the following code cause and exception? I thought that the >> left hand side of := was not evaluated. >> >> Clear[a, z]; >> z[x_Integer] := 2; >> z[x_] := Throw[11]; >> a[i_, iUp_?z] := 3; >> a[i_Integer, iUp_?z] := 5; >> >> Cheers, >> Hein > > -- majort at cox-internet.com Bobby R. Treat
- References:
- Re: bug with definitions?
- From: Jens-Peer Kuska <kuska@informatik.uni-leipzig.de>
- Re: bug with definitions?