[Toybox] test.c patches on GitHub

[Andy Chu]

POSIX specifies that it *should* be inconsistent, i.e. the cases with 0, 1,
2, 3, and 4 args are different than the cases with 5 or more args.  As
always, this appears to be a historical compromise to reconcile the
behavior of different shells in common cases.

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html (scroll
down)

Post I wrote about it here (after implementing it):
http://www.oilshell.org/blog/2017/08/31.html

Andy







On Wed, Sep 5, 2018 at 6:45 PM Kevin Spiteri <kspiteri at ieee.org> wrote:

> I'm not sure coreutils is consistent.
>
> [ ! "" -o s ] is false, so -o has higher priority than ! here, but
> [ ! 1 -eq 2 -o s ] is true, so ! has higher priority than -o here.
> Changing either 1 or 2 with walrus gives the integer expression expected
> error.
>
> [ ! '"" -a "" ] is true, so -a has higher priority than ! here, but
> [ s -a ! "" -a "" ] is false, so ! has higher priority than the right -a
> here.
>
> I think the precedence should be as simple as:
> 1. anything enclosed in ( )
> 2. any expression not containing !, -a, -o
> 3. !
> 4. -a
> 5. -o
>
> Of course, matching coreutils is more important than matching what I
> think. But I'm not sure how to get a consistent set of rules short of
> reading the code and mirroring it.
>
> Kevin
>
>
> On Wed, Sep 5, 2018 at 3:24 PM Rob Landley <rob at landley.net> wrote:
>
>> On 09/05/2018 01:21 PM, Rob Landley wrote:
>> > Ah, I remember what the big timesink for this one is: [ TEST -a TEST -o
>> TEST -a
>> > TEST ] needs a loop, which is reminiscent of the logic in "find" which
>> meant I
>> > wanted to look at the find code to see if anything there was worth
>> factoring out
>> > into lib so it could be shared.
>>
>> I should copy a bunch of the tests from "find" with regard to ! inside
>> parentheses meaning something different from ! outside parentheses and
>> such, I
>> think I wrote about this in old mailing post lists, I should compare the
>> git
>> commit dates with the web archive and see what i can dig up?
>>
>> I left myself comments at the end of tests/test.test (what a lovely name);
>>
>> # test ! = -o a
>> # test ! \( = -o a \)
>> # test \( ! = \) -o a
>>
>> And I dunno what the priority of -a and -o are here:
>>
>> [ 1 -a "" -a "" -o 1 -a 1 ]
>>
>> (Let's see, find is doing something like -a chains fast forward on
>> failure, and
>> -o chains fast forward on success? There's conditional evaluation in find
>> that
>> doesn't seem to be the case here:
>>
>> $ test 1 -o 3 -gt walrus
>> bash: test: walrus: integer expression expected
>>
>> Confirm ] only matters as last argument when name is [
>>
>> [ ] = ] ]
>>
>> And of course gratuitous parentheses:
>>
>> [ \( 1 -lt 2 \) ]
>>
>> (So often coming up with the tests to run is the hard part and
>> development's at
>> most half the work...)
>>
>> Rob
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>>
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