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* indirect assignment to array
@ 2020-04-15 23:01 Pier Paolo Grassi
  2020-04-15 23:13 ` Mikael Magnusson
  0 siblings, 1 reply; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-15 23:01 UTC (permalink / raw)
  To: Zsh-Users List

[-- Attachment #1: Type: text/plain, Size: 335 bytes --]

Hello, I'm trying to assign the content of an array to another which name
is contained in a variable
What I tried:

varname=newarray
typeset -a array=(1 2 3)
typeset -a $varname=($array)

but I get an
zsh: bad pattern: newarray=(1

are there other methods to do indirect assignment that allow me to do this?

thanks

Pier Paolo Grassi

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-15 23:01 indirect assignment to array Pier Paolo Grassi
@ 2020-04-15 23:13 ` Mikael Magnusson
  2020-04-15 23:42   ` Pier Paolo Grassi
                     ` (2 more replies)
  0 siblings, 3 replies; 15+ messages in thread
From: Mikael Magnusson @ 2020-04-15 23:13 UTC (permalink / raw)
  To: Pier Paolo Grassi; +Cc: Zsh-Users List

On 4/16/20, Pier Paolo Grassi <pierpaolog@gmail.com> wrote:
> Hello, I'm trying to assign the content of an array to another which name
> is contained in a variable
> What I tried:
>
> varname=newarray
> typeset -a array=(1 2 3)
> typeset -a $varname=($array)
>
> but I get an
> zsh: bad pattern: newarray=(1
>
> are there other methods to do indirect assignment that allow me to do this?

: ${(PA)varname::=$array}
(leave out the A for scalar assignment, and use AA for assoc arrays).

-- 
Mikael Magnusson

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-15 23:13 ` Mikael Magnusson
@ 2020-04-15 23:42   ` Pier Paolo Grassi
  2020-04-15 23:54     ` Bart Schaefer
  2020-04-16 16:28   ` Sebastian Gniazdowski
       [not found]   ` <CAP+y1xAG3ayQNE3JqeF_YOT5FZ9pLiUAF5TmPVoOv+nPyjK30A__22203.4378488146$1586994256$gmane$org@mail.gmail.com>
  2 siblings, 1 reply; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-15 23:42 UTC (permalink / raw)
  To: Mikael Magnusson; +Cc: Zsh-Users List

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Thanks! I was afraid I had to resort to eval.
By the way, I was trying to create an helper function like this:

debugvar(){
    typeset -g $1
    typeset +m $1
    typeset $1
}

but I found out from the manual that -g "it has no effect when listing
existing parameters"

is there a way to use typeset from functions to print out the definition of
global variables?

thanks again

Pier Paolo Grassi


Il giorno gio 16 apr 2020 alle ore 01:13 Mikael Magnusson <mikachu@gmail.com>
ha scritto:

> On 4/16/20, Pier Paolo Grassi <pierpaolog@gmail.com> wrote:
> > Hello, I'm trying to assign the content of an array to another which name
> > is contained in a variable
> > What I tried:
> >
> > varname=newarray
> > typeset -a array=(1 2 3)
> > typeset -a $varname=($array)
> >
> > but I get an
> > zsh: bad pattern: newarray=(1
> >
> > are there other methods to do indirect assignment that allow me to do
> this?
>
> : ${(PA)varname::=$array}
> (leave out the A for scalar assignment, and use AA for assoc arrays).
>
> --
> Mikael Magnusson
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-15 23:42   ` Pier Paolo Grassi
@ 2020-04-15 23:54     ` Bart Schaefer
  2020-04-16  0:05       ` Pier Paolo Grassi
  0 siblings, 1 reply; 15+ messages in thread
From: Bart Schaefer @ 2020-04-15 23:54 UTC (permalink / raw)
  To: Pier Paolo Grassi; +Cc: Zsh-Users List

On Wed, Apr 15, 2020 at 4:43 PM Pier Paolo Grassi <pierpaolog@gmail.com> wrote:
>
> is there a way to use typeset from functions to print out the definition of
> global variables?

typeset -p should do it, as long as a parameter of the same name has
not already been declared local.

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-15 23:54     ` Bart Schaefer
@ 2020-04-16  0:05       ` Pier Paolo Grassi
  2020-04-16  0:12         ` Bart Schaefer
  0 siblings, 1 reply; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-16  0:05 UTC (permalink / raw)
  To: Bart Schaefer; +Cc: Zsh-Users List

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I see, for debug purposes it works indeed, but I don't have the output of
typeset +m
that would have printed array for array parameters. I wanted to capture
that output to test for variables of type array.
Is there a way to test if a variable is of type array?

regards

Pier Paolo Grassi
linkedin: https://www.linkedin.com/in/pier-paolo-grassi-19300217
founder: https://www.meetup.com/it-IT/Machine-Learning-TO


Il giorno gio 16 apr 2020 alle ore 01:55 Bart Schaefer <
schaefer@brasslantern.com> ha scritto:

> On Wed, Apr 15, 2020 at 4:43 PM Pier Paolo Grassi <pierpaolog@gmail.com>
> wrote:
> >
> > is there a way to use typeset from functions to print out the definition
> of
> > global variables?
>
> typeset -p should do it, as long as a parameter of the same name has
> not already been declared local.
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-16  0:05       ` Pier Paolo Grassi
@ 2020-04-16  0:12         ` Bart Schaefer
  2020-04-16 16:02           ` Pier Paolo Grassi
  0 siblings, 1 reply; 15+ messages in thread
From: Bart Schaefer @ 2020-04-16  0:12 UTC (permalink / raw)
  To: Pier Paolo Grassi; +Cc: Zsh-Users List

On Wed, Apr 15, 2020 at 5:06 PM Pier Paolo Grassi <pierpaolog@gmail.com> wrote:
>
> Is there a way to test if a variable is of type array?

var=module_path
print -r ${(tP)var} $var

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-16  0:12         ` Bart Schaefer
@ 2020-04-16 16:02           ` Pier Paolo Grassi
  0 siblings, 0 replies; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-16 16:02 UTC (permalink / raw)
  To: Bart Schaefer; +Cc: Zsh-Users List

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cool, thanks!

Pier Paolo Grassi
linkedin: https://www.linkedin.com/in/pier-paolo-grassi-19300217
founder: https://www.meetup.com/it-IT/Machine-Learning-TO


Il giorno gio 16 apr 2020 alle ore 02:12 Bart Schaefer <
schaefer@brasslantern.com> ha scritto:

> On Wed, Apr 15, 2020 at 5:06 PM Pier Paolo Grassi <pierpaolog@gmail.com>
> wrote:
> >
> > Is there a way to test if a variable is of type array?
>
> var=module_path
> print -r ${(tP)var} $var
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-15 23:13 ` Mikael Magnusson
  2020-04-15 23:42   ` Pier Paolo Grassi
@ 2020-04-16 16:28   ` Sebastian Gniazdowski
  2020-04-16 18:04     ` Pier Paolo Grassi
       [not found]     ` <CAP+y1xDa=fUvaP=gwbawRmcfwjq0ZH1KEnt=wTX4zOKaT4mzyQ__13411.9792653777$1587060411$gmane$org@mail.gmail.com>
       [not found]   ` <CAP+y1xAG3ayQNE3JqeF_YOT5FZ9pLiUAF5TmPVoOv+nPyjK30A__22203.4378488146$1586994256$gmane$org@mail.gmail.com>
  2 siblings, 2 replies; 15+ messages in thread
From: Sebastian Gniazdowski @ 2020-04-16 16:28 UTC (permalink / raw)
  To: Mikael Magnusson; +Cc: Pier Paolo Grassi, Zsh-Users List

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On Thu, 16 Apr 2020 at 01:14, Mikael Magnusson <mikachu@gmail.com> wrote:

> : ${(PA)varname::=$array}
> (leave out the A for scalar assignment, and use AA for assoc arrays).
>

I would do:

: ${(PA)varname::="$array[@]"}

to not lose empty elements.

-- 
Sebastian Gniazdowski
News: https://twitter.com/ZdharmaI
IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zinit
Blog: http://zdharma.org

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
       [not found]   ` <CAP+y1xAG3ayQNE3JqeF_YOT5FZ9pLiUAF5TmPVoOv+nPyjK30A__22203.4378488146$1586994256$gmane$org@mail.gmail.com>
@ 2020-04-16 16:30     ` Stephane Chazelas
  2020-04-16 16:37       ` Pier Paolo Grassi
  0 siblings, 1 reply; 15+ messages in thread
From: Stephane Chazelas @ 2020-04-16 16:30 UTC (permalink / raw)
  To: Pier Paolo Grassi; +Cc: Mikael Magnusson, Zsh-Users List

2020-04-16 01:42:29 +0200, Pier Paolo Grassi:
> Il giorno gio 16 apr 2020 alle ore 01:13 Mikael Magnusson <mikachu@gmail.com>
> ha scritto:
[...]
> > : ${(PA)varname::=$array}
> > (leave out the A for scalar assignment, and use AA for assoc arrays).
[...]
> Thanks! I was afraid I had to resort to eval.
[...]

What's wrong with "eval"? Note that many of those alternatives
to "eval" are just other evals in disguise or are as dangerous
(but giving the wrong impression that they're not).

: ${(PA)varname::=$array}

is a command injection vulnerability if the content of $varname
is not sanitized.


$ varname='x[$(uname>&2)]'
$ : ${(PA)varname::=$array}
Linux
zsh: bad math expression: empty string

So is:

eval $varname'=("$array[@]")'

but at least it's more obvious that it is.

In any case, I'd expect the contents of $varname to be known and
trusted in this case, while that of $array could be anything.

Note that that "$array[@]" (instead of $array) is needed to
preserve empty elements.

-- 
Stephane

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-16 16:30     ` indirect assignment to array Stephane Chazelas
@ 2020-04-16 16:37       ` Pier Paolo Grassi
  2020-04-16 17:37         ` Bart Schaefer
  0 siblings, 1 reply; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-16 16:37 UTC (permalink / raw)
  To: Pier Paolo Grassi, Mikael Magnusson, Zsh-Users List

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thanks Stephane, it is indeed a good habit to sanitize the varname
whichever method is utilized. From your explanation I admit the eval
solution would have been equally valid
regards

Pier Paolo Grassi
linkedin: https://www.linkedin.com/in/pier-paolo-grassi-19300217
founder: https://www.meetup.com/it-IT/Machine-Learning-TO


Il giorno gio 16 apr 2020 alle ore 18:30 Stephane Chazelas <
stephane@chazelas.org> ha scritto:

> 2020-04-16 01:42:29 +0200, Pier Paolo Grassi:
> > Il giorno gio 16 apr 2020 alle ore 01:13 Mikael Magnusson <
> mikachu@gmail.com>
> > ha scritto:
> [...]
> > > : ${(PA)varname::=$array}
> > > (leave out the A for scalar assignment, and use AA for assoc arrays).
> [...]
> > Thanks! I was afraid I had to resort to eval.
> [...]
>
> What's wrong with "eval"? Note that many of those alternatives
> to "eval" are just other evals in disguise or are as dangerous
> (but giving the wrong impression that they're not).
>
> : ${(PA)varname::=$array}
>
> is a command injection vulnerability if the content of $varname
> is not sanitized.
>
>
> $ varname='x[$(uname>&2)]'
> $ : ${(PA)varname::=$array}
> Linux
> zsh: bad math expression: empty string
>
> So is:
>
> eval $varname'=("$array[@]")'
>
> but at least it's more obvious that it is.
>
> In any case, I'd expect the contents of $varname to be known and
> trusted in this case, while that of $array could be anything.
>
> Note that that "$array[@]" (instead of $array) is needed to
> preserve empty elements.
>
> --
> Stephane
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-16 16:37       ` Pier Paolo Grassi
@ 2020-04-16 17:37         ` Bart Schaefer
  2020-04-16 17:43           ` Pier Paolo Grassi
  0 siblings, 1 reply; 15+ messages in thread
From: Bart Schaefer @ 2020-04-16 17:37 UTC (permalink / raw)
  To: Zsh-Users List

"Sanitizing" a varname for (P) expansion is context-dependent.  For
example, this is "legal":

varname='x[$(echo 3)]'
: ${(AP)varname::=foo}

The point being, there's no straightforward internal test that zsh
could apply to ${(P)varname} that would correctly reject "unsanitary"
references.  I suppose we could do something similar to Perl's taint
checks and prevent (P) from being used on environment variables that
have not been (re)assigned since the current shell started up.

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-16 17:37         ` Bart Schaefer
@ 2020-04-16 17:43           ` Pier Paolo Grassi
  0 siblings, 0 replies; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-16 17:43 UTC (permalink / raw)
  To: Bart Schaefer; +Cc: Zsh-Users List

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my personal sanitization test is:

[[ ! $var =~ '^[a-zA-Z_][a-zA-Z_0-9]*$' ]] && { error "msg", return 1}

Pier Paolo Grassi
linkedin: https://www.linkedin.com/in/pier-paolo-grassi-19300217
founder: https://www.meetup.com/it-IT/Machine-Learning-TO


Il giorno gio 16 apr 2020 alle ore 19:39 Bart Schaefer <
schaefer@brasslantern.com> ha scritto:

> "Sanitizing" a varname for (P) expansion is context-dependent.  For
> example, this is "legal":
>
> varname='x[$(echo 3)]'
> : ${(AP)varname::=foo}
>
> The point being, there's no straightforward internal test that zsh
> could apply to ${(P)varname} that would correctly reject "unsanitary"
> references.  I suppose we could do something similar to Perl's taint
> checks and prevent (P) from being used on environment variables that
> have not been (re)assigned since the current shell started up.
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: indirect assignment to array
  2020-04-16 16:28   ` Sebastian Gniazdowski
@ 2020-04-16 18:04     ` Pier Paolo Grassi
       [not found]     ` <CAP+y1xDa=fUvaP=gwbawRmcfwjq0ZH1KEnt=wTX4zOKaT4mzyQ__13411.9792653777$1587060411$gmane$org@mail.gmail.com>
  1 sibling, 0 replies; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-16 18:04 UTC (permalink / raw)
  To: Sebastian Gniazdowski; +Cc: Mikael Magnusson, Zsh-Users List

[-- Attachment #1: Type: text/plain, Size: 1020 bytes --]

>: ${(PA)varname::="$array[@]"}
>
>to not lose empty elements.

this (very useful) clarification has made me embark in a three hour long
quest to correct (some of?) the many places where I indeed was loosing
empty elements
thanks but I really hate when I find out bugs that i never have thought of
(a big one has been discovering the -r flag to read)
one should indeed always rtfm, and I really enjoy doing it, but there are
so many to read and so few hours in a day...

Pier Paolo Grassi

Il giorno gio 16 apr 2020 alle ore 18:29 Sebastian Gniazdowski <
sgniazdowski@gmail.com> ha scritto:

> On Thu, 16 Apr 2020 at 01:14, Mikael Magnusson <mikachu@gmail.com> wrote:
>
>> : ${(PA)varname::=$array}
>> (leave out the A for scalar assignment, and use AA for assoc arrays).
>>
>
> I would do:
>
> : ${(PA)varname::="$array[@]"}
>
> to not lose empty elements.
>
> --
> Sebastian Gniazdowski
> News: https://twitter.com/ZdharmaI
> IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zinit
> Blog: http://zdharma.org
>

^ permalink raw reply	[flat|nested] 15+ messages in thread

* read -r and bad surprises (Was: indirect assignment to array)
       [not found]     ` <CAP+y1xDa=fUvaP=gwbawRmcfwjq0ZH1KEnt=wTX4zOKaT4mzyQ__13411.9792653777$1587060411$gmane$org@mail.gmail.com>
@ 2020-04-16 20:24       ` Stephane Chazelas
  2020-04-16 21:06         ` Pier Paolo Grassi
  0 siblings, 1 reply; 15+ messages in thread
From: Stephane Chazelas @ 2020-04-16 20:24 UTC (permalink / raw)
  To: Pier Paolo Grassi; +Cc: Sebastian Gniazdowski, Mikael Magnusson, Zsh-Users List

2020-04-16 20:04:57 +0200, Pier Paolo Grassi:
[...]
> thanks but I really hate when I find out bugs that i never have thought of
> (a big one has been discovering the -r flag to read)
[...]

While you're there, note that the syntax to read a line of input
verbatim is:

IFS= read -r line

not just read -r line.

Compare:

$ print -r ' a\b ' | IFS= read -r a; printf '<%s>\n' $a
< a\b >
$ print -r ' a\b ' | read -r a; printf '<%s>\n' $a
<a\b>
$ print -r ' a\b ' | read a; printf '<%s>\n' $a
<ab>

See https://unix.stackexchange.com/questions/209123/understanding-ifs-read-r-line
for details.

-- 
Stephane

^ permalink raw reply	[flat|nested] 15+ messages in thread

* Re: read -r and bad surprises (Was: indirect assignment to array)
  2020-04-16 20:24       ` read -r and bad surprises (Was: indirect assignment to array) Stephane Chazelas
@ 2020-04-16 21:06         ` Pier Paolo Grassi
  0 siblings, 0 replies; 15+ messages in thread
From: Pier Paolo Grassi @ 2020-04-16 21:06 UTC (permalink / raw)
  To: Mikael Magnusson, Pier Paolo Grassi, Sebastian Gniazdowski,
	Zsh-Users List

[-- Attachment #1: Type: text/plain, Size: 1040 bytes --]

thanks, fortunately I already crossed that bridge, as my read alias can
testify:

alias \read
read='IFS='''' read -r'

Pier Paolo Grassi
linkedin: https://www.linkedin.com/in/pier-paolo-grassi-19300217
founder: https://www.meetup.com/it-IT/Machine-Learning-TO


Il giorno gio 16 apr 2020 alle ore 22:24 Stephane Chazelas <
stephane@chazelas.org> ha scritto:

> 2020-04-16 20:04:57 +0200, Pier Paolo Grassi:
> [...]
> > thanks but I really hate when I find out bugs that i never have thought
> of
> > (a big one has been discovering the -r flag to read)
> [...]
>
> While you're there, note that the syntax to read a line of input
> verbatim is:
>
> IFS= read -r line
>
> not just read -r line.
>
> Compare:
>
> $ print -r ' a\b ' | IFS= read -r a; printf '<%s>\n' $a
> < a\b >
> $ print -r ' a\b ' | read -r a; printf '<%s>\n' $a
> <a\b>
> $ print -r ' a\b ' | read a; printf '<%s>\n' $a
> <ab>
>
> See
> https://unix.stackexchange.com/questions/209123/understanding-ifs-read-r-line
> for details.
>
> --
> Stephane
>
-- 
Pier Paolo Grassi

^ permalink raw reply	[flat|nested] 15+ messages in thread

end of thread, other threads:[~2020-04-16 21:06 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-04-15 23:01 indirect assignment to array Pier Paolo Grassi
2020-04-15 23:13 ` Mikael Magnusson
2020-04-15 23:42   ` Pier Paolo Grassi
2020-04-15 23:54     ` Bart Schaefer
2020-04-16  0:05       ` Pier Paolo Grassi
2020-04-16  0:12         ` Bart Schaefer
2020-04-16 16:02           ` Pier Paolo Grassi
2020-04-16 16:28   ` Sebastian Gniazdowski
2020-04-16 18:04     ` Pier Paolo Grassi
     [not found]     ` <CAP+y1xDa=fUvaP=gwbawRmcfwjq0ZH1KEnt=wTX4zOKaT4mzyQ__13411.9792653777$1587060411$gmane$org@mail.gmail.com>
2020-04-16 20:24       ` read -r and bad surprises (Was: indirect assignment to array) Stephane Chazelas
2020-04-16 21:06         ` Pier Paolo Grassi
     [not found]   ` <CAP+y1xAG3ayQNE3JqeF_YOT5FZ9pLiUAF5TmPVoOv+nPyjK30A__22203.4378488146$1586994256$gmane$org@mail.gmail.com>
2020-04-16 16:30     ` indirect assignment to array Stephane Chazelas
2020-04-16 16:37       ` Pier Paolo Grassi
2020-04-16 17:37         ` Bart Schaefer
2020-04-16 17:43           ` Pier Paolo Grassi

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