Re: Help-bash Digest, Vol 113, Issue 21

[Budi]

How to expand only bash $variable at any certain point of anything
(time, condition, etc) ?
as this works :
  i=1
  u="sum = $i + \$o"
  o=two; n=$(eval echo $u)

to equalize to n='sum = 1 + two'

the truth,  $(eval echo $)  won't work for complex long expression
The real case the u above is some find arguments as, e.g., the output of set -x:
C='( -ipath /home/olive/build/CMakeFiles/* (  ( -type d ( -regex
.*\s.* -printf '\''%p/'\''\n -o -printf %p/\n ) -o ( -regex .*\s.*
-printf '\''%p'\''\n -o -printf %p\n ) ) ) -o -ipath
/home/olive/build/CMakeFiles -type f ( -regex .*\s.* -printf
'\''%p'\''\n -o -printf %p\n ) -o -iregex .{17}/.+/CMakeFiles$RP (
-type d ( -regex .*\s.* -printf '\''%p/'\''\n -o -printf %p/\n ) -o (
-regex .*\s.* -printf '\''%p'\''\n -o -printf %p\n ) ) )'

So $RP there is big need to be expanded after once expansion, like $o sample.

So how to expand only a bash variable at any certain arbitrary point
without touch any else expression in which the var. sit



On 3/13/21, help-bash-request@gnu.org <help-bash-request@gnu.org> wrote:
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> Today's Topics:
>
>    1. Re: idea about negative indexed array keys (Alex fxmbsw7 Ratchev)
>    2. Re: quote interpretation via vars without eval
>       (Lawrence Velázquez)
>    3. Re: quote interpretation via vars without eval
>       (Alex fxmbsw7 Ratchev)
>    4. Re: quote interpretation via vars without eval (Chet Ramey)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 13 Mar 2021 16:32:33 +0100
> From: Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
> To: help-bash <help-bash@gnu.org>
> Subject: Re: idea about negative indexed array keys
> Message-ID:
>       <CAALKErE0eVucQJ2HsgdurqQHMDmjzdzE59U==jm+oRFffYx7xw@mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> correction of text
>
> past week*s*
>
> *and i know it didnt happen with bash 4 cause i dont have bash 4 since
> looong*
> *who knows what's been*
>
> On Sat, Mar 13, 2021 at 3:43 PM Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
> wrote:
>
>> this one looks exactly like the one i rememeber
>> but there are factical mismatches, it happened in the past week, with bash
>> 5.1.4-maint
>> but seemfully somewhere else than direct array index
>>
>> On Sat, Mar 13, 2021 at 3:36 PM Greg Wooledge <greg@wooledge.org> wrote:
>>
>>> On Fri, Mar 12, 2021 at 05:11:19PM -0500, Eli Schwartz wrote:
>>> > On 3/12/21 4:58 PM, Alex fxmbsw7 Ratchev wrote:
>>> > > i saw, ${arr[-1]} == syntax error
>>> > >
>>> > > what about implenting it, -0 is the last -1 is the second last etc
>>> > >
>>> > > such negative values are already in ${..:<>:<>} implented, as a good
>>> small
>>> > > statement for the same style
>>> >
>>> > How did you accomplish the task of getting a syntax error for this? I
>>> > managed it with:
>>> >
>>> > $ declare arr=(foo bar baz "syntax error")
>>> > $ echo "${arr[-1]}"; echo "${arr[-2]}"
>>> > syntax error
>>> > baz
>>>
>>> unicorn:~$ bash-4.1 -c 'a=(a b c); echo "${a[-1]}"'
>>> bash-4.1: a: bad array subscript
>>>
>>> unicorn:~$ bash-4.2 -c 'a=(a b c); echo "${a[-1]}"'
>>> c
>>>
>>> Is that close enough?
>>>
>>>
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 13 Mar 2021 10:41:06 -0500
> From: Lawrence Velázquez <vq@larryv.me>
> To: Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
> Cc: Koichi Murase <myoga.murase@gmail.com>, help-bash@gnu.org
> Subject: Re: quote interpretation via vars without eval
> Message-ID: <6CF08637-6DB7-4298-8B37-4B62F61FDA4B@larryv.me>
> Content-Type: text/plain;     charset=us-ascii
>
>> On Mar 13, 2021, at 10:02 AM, Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
>> wrote:
>>
>> i had many such advices, about oudated wrong formatting rules
>
> Consider the possibility that standards and conventions are not,
> in fact, always "outdated" and "wrong", even if you don't understand
> or like them.
>
>> there is also misunderstanding totally
>> settment i meant, by set-ing
>> also you misunderstood my quotes question
>
> You should not be surprised when the rest of us fail to understand
> your avant-garde grammar, syntax, and vocabulary.
>
>> it was related to internal parsing of bash of strings
>> not arguments
>> i set declare [-opts] "$var" where $var is complex array stuff
>
> There might have been less of a "misunderstanding" if you'd actually
> mentioned this in your original email.
>
> vq
>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 13 Mar 2021 16:51:18 +0100
> From: Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
> To: Lawrence Velázquez <vq@larryv.me>
> Cc: Koichi Murase <myoga.murase@gmail.com>, help-bash
>       <help-bash@gnu.org>
> Subject: Re: quote interpretation via vars without eval
> Message-ID:
>       <CAALKErEiGjfH_6OjtDeYNGADzyKWBg0K=Wg2Dqu6BveYkciX7g@mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> you know, you didnt spend 10 years and still around psychiatry aka poison
> prison cause your parents lied you in there, and where is your public self
> written server site and stuff for public
> i had it, ill do it again
>
> from my 1. mail :
> 'i was doing declare -p to again modifications'
> 'noticed i can include quotes inside the declare settment ( declare [-opts]
> "$res" )'
>
> $res being the most common var name for str to result modifications i know
>
> 'backslashes, quotes, etc, in vars, as arguments' <- as arguments there i
> mention args cause thats a declare arg amd i am or was looking for making
> shell quoting or more features separately expand
> instead of having to eval
>
> peace
>
> On Sat, Mar 13, 2021 at 4:41 PM Lawrence Velázquez <vq@larryv.me> wrote:
>
>> > On Mar 13, 2021, at 10:02 AM, Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
>> wrote:
>> >
>> > i had many such advices, about oudated wrong formatting rules
>>
>> Consider the possibility that standards and conventions are not,
>> in fact, always "outdated" and "wrong", even if you don't understand
>> or like them.
>>
>> > there is also misunderstanding totally
>> > settment i meant, by set-ing
>> > also you misunderstood my quotes question
>>
>> You should not be surprised when the rest of us fail to understand
>> your avant-garde grammar, syntax, and vocabulary.
>>
>> > it was related to internal parsing of bash of strings
>> > not arguments
>> > i set declare [-opts] "$var" where $var is complex array stuff
>>
>> There might have been less of a "misunderstanding" if you'd actually
>> mentioned this in your original email.
>>
>> vq
>
>
> ------------------------------
>
> Message: 4
> Date: Sat, 13 Mar 2021 11:53:10 -0500
> From: Chet Ramey <chet.ramey@case.edu>
> To: Koichi Murase <myoga.murase@gmail.com>, Alex fxmbsw7 Ratchev
>       <fxmbsw7@gmail.com>
> Cc: chet.ramey@case.edu, help-bash <help-bash@gnu.org>
> Subject: Re: quote interpretation via vars without eval
> Message-ID: <6ca00a77-b931-93d5-3746-8b2d393e0283@case.edu>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> On 3/13/21 6:35 AM, Koichi Murase wrote:
>> 2021年3月13日(土) 7:59 Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>:
>>> i was doing declare -p to again modifications, and noticed i can include
>>> quotes inside the declare settment ( declare [-opts] "$res" )
>>> where else do the quotes get interpreted, can you write a short list ?
>>
>> `declare' is a command that takes string arguments [but with an
>> exception for the array assignments of the form `arr=(...)']. You can
>> quote them since they are treated as normal arguments.
>
> Not exactly. Builtins like `declare' and `local' (and `export' and
> `readonly') that accept assignment statements are so-called "declaration
> commands."
>
> If the shell can recognize the argument to a declaration command as an
> assignment statement while parsing, it's subjected to the same
> expansions as an assignment statement. In particular, that means pathname
> expansion and word splitting are not performed.
>
> POSIX approved an interpretation concerning "declaration utilities" back in
> 2011, and it will be a part of the upcoming issue 8.
>
> https://www.austingroupbugs.net/view.php?id=351
>
> Bash-4.0 and later versions attempt to expand assignment statement
> arguments to declaration commands the same way as standalone assignment
> statements.
>
> --
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
>                ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/
>
>
>
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> End of Help-bash Digest, Vol 113, Issue 21
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