Re: Quit versus Clear["Global`*"]

*To*: mathgroup at smc.vnet.net*Subject*: [mg121280] Re: Quit versus Clear["Global`*"]*From*: "Oleksandr Rasputinov" <oleksandr_rasputinov at hmamail.com>*Date*: Wed, 7 Sep 2011 05:40:03 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <201109042206.SAA21533@smc.vnet.net> <j44k53$94d$1@smc.vnet.net>

Quit[Abort[]] doesn't quit; instead it gives $Aborted. (I dare say as expected.) Quit vs. Quit[] performing the same operation isn't a great mystery: one can define f := a and f[args___] := a and get the same result regardless of whether f is called as f or f[...]. In general DownValues and OwnValues don't work like this, but providing for such behaviour in a specific case is easy. On Tue, 06 Sep 2011 09:03:47 +0100, DrMajorBob <btreat1 at austin.rr.com> wrote: > Quit appears to quit as soon as it is parsed, regardless of arguments... > yet another poster found that, if it is the first line in a cell with > other statements, Mathematica doesn't quit until those other statements > are done, hence wiping out their effect. > > Quit[e] the conundrum. > > Bobby > > On Mon, 05 Sep 2011 13:15:07 -0500, Andrzej Kozlowski <akoz at mimuw.edu.pl> > wrote: > >> Well, I see it differently. All Mathematica functions have the form >> Head[arguments] where the number of arguments could be 0. Quit is >> therefore a Mathematica function, like Print[], Return[]. In fact, >> Quit[n] where n is an integer also works "passing the integer n as an >> exit code to the operating system" whatever that means. On the other >> hand, expressions of the form Abracadabra are normally just symbols and >> normally they do not perform any actions. In fact, do you know of any >> other example (except Quit) when when evaluating a symbols actually does >> more than return a value (that usually happens in the case of global >> constants, whose names begin with $, >> >> [1]:= $Version >> >> Out[1]= 8.0 for Mac OS X x86 (64-bit) (February 23, 2011) >> >> Note, by the way, that Abort[] works but Abort does not: >> >> In[3]:= Print[a];Abort[];Print[b] >> During evaluation of In[3]:= a >> Out[3]= $Aborted >> >> Print[a];Abort;Print[b] >> a >> b >> >> Andrzej Kozlowski >> >> On 5 Sep 2011, at 19:44, DrMajorBob wrote: >> >>> I, on the other hand, never saw Quit[] until this thread began. >>> >>> I suppose it figures that if Quit kills the kernel, then also Quit[any >>> arguments or none] might also kill the kernel. (The other way 'round >>> doesn't necessarily "figure", on the other hand.) >>> >>> Bobby >>> >>> On Mon, 05 Sep 2011 07:44:17 -0500, Andrzej Kozlowski >>> <akoz at mimuw.edu.pl> wrote: >>> >>>> Actually (as far as I can tell) Quit is undocumented but Quit[] is: >>>> >>>> ?Quit >>>> Quit[] terminates a Mathematica kernel session. >>>> >>>> I thought you had made a mistake but I tired just Quit (without the >>>> brackets) and was surprised (after all these years!) to see it work. I >>>> am wondering if there are more cases like this? >>>> >>>> Andrzej Kozlowski >>>> >>>> On 5 Sep 2011, at 13:06, DrMajorBob wrote: >>>> >>>>> No. For that, you need: >>>>> >>>>> Quit >>>>> >>>>> Bobby >>>>> >>>>> On Sun, 04 Sep 2011 17:06:32 -0500, Themis Matsoukas >>>>> <tmatsoukas at me.com> >>>>> wrote: >>>>> >>>>>> So, if I use ClearAll["Global`*"] at the beginning of a notebook and >>>>>> execute all the cells, is it the same as running on a fresh kernel? >>>>>> >>>>>> Themis >>>>>> >>>>> -- >>>>> DrMajorBob at yahoo.com >>>>> >>>> >>> -- >>> DrMajorBob at yahoo.com

**Follow-Ups**:**Re: Quit versus Clear["Global`*"]***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**References**:**Re: Quit versus Clear["Global`*"]***From:*Themis Matsoukas <tmatsoukas@me.com>