kinda perl split ...

kinda perl split ...

[Marc Chantreux]

Hi all,

i'm always searching for shortest ways in zsh (coming from perl world).

in perl :

while ( <>) {
	chomp;
	my ( $a , $b ) = split /\t/;
	print "b=$b a=$a"
}

in zsh :

while {read} {
	content=( ${(ps:\t:)REPLY} )
	a=$content[1]
	b=content[2]
	print "b=$b a=$a"
}

is there something more faster to initialize a and b (peraps closer than 
split) ?

regards
mc

Re: kinda perl split ...

[Dominic Mitchell]

On Tue, Mar 21, 2006 at 02:42:12PM +0100, Marc Chantreux wrote:
> Hi all,
> 
> i'm always searching for shortest ways in zsh (coming from perl world).
> 
> in perl :
> 
> while ( <>) {
> 	chomp;
> 	my ( $a , $b ) = split /\t/;
> 	print "b=$b a=$a"
> }
> 
> in zsh :
> 
> while {read} {
> 	content=( ${(ps:\t:)REPLY} )
> 	a=$content[1]
> 	b=content[2]
> 	print "b=$b a=$a"
> }
> 
> is there something more faster to initialize a and b (peraps closer than 
> split) ?

Just use the read builtin:

  echo foo bar | while read a b junk
  do
    echo "a=$a b=$b"
  done

I've got a habit of reading any remaining fields into a variable called
"junk", just in case.

-Dom

Re: kinda perl split ...

[Marc Chantreux]

Dominic Mitchell wrote:

>   echo foo bar | while read a b junk
>   do
>     echo "a=$a b=$b"
>   done


so if the separator is ':', you should redefine IFS

oldIFS=$IFS
IFS=':'
echo foo bar | while read a b junk
do
      echo "a=$a b=$b"
done
IFS=$oldIFS
oldIFS=

or with a subshell:

( IFS=':'
echo foo bar | while read a b junk
do
      echo "a=$a b=$b"
done )

Re: kinda perl split ...

[Dominic Mitchell]

On Tue, Mar 21, 2006 at 03:22:29PM +0100, Marc Chantreux wrote:
> Dominic Mitchell wrote:
> 
> >  echo foo bar | while read a b junk
> >  do
> >    echo "a=$a b=$b"
> >  done
> 
> so if the separator is ':', you should redefine IFS
> 
> oldIFS=$IFS
> IFS=':'
> echo foo bar | while read a b junk
> do
>      echo "a=$a b=$b"
> done
> IFS=$oldIFS
> oldIFS=
> 
> or with a subshell:
> 
> ( IFS=':'
> echo foo bar | while read a b junk
> do
>      echo "a=$a b=$b"
> done )

Or even simpler, just redefine the variable for that read command:

    echo foo:bar | while IFS=: read a b junk
    do
        echo "a=$a b=$b"
    done

-Dom

Re: kinda perl split ...

[Marc Chantreux]

hi again,

what about this perl code ?

my %user;

@user{qw( login passwd )} = split /:/;

i've tried something there... peraps it's a good tips :

http://khatar.phear.org/shell/zshEnum.html

(comments are in french but zsh workers can ignore them).

regards
mc

Re: kinda perl split ...

[Bart Schaefer]

On Mar 21,  4:33pm, Marc Chantreux wrote:
}
} my %user;
} @user{qw( login passwd )} = split /:/;

You can still use "read".

  local -A user
  while IFS=: read 'user['${^=:-login passwd uid gid gecos home shell}']'
  do
    if (( ${user[uid]} > 100 )) { print $user[login] }
  done < /etc/passwd

} http://khatar.phear.org/shell/zshEnum.html

A better way to write "enum":

  enum() {
    integer i=0
    eval integer -g $^@='$[++i]'
  }

Then you don't need "eval $(enum ...)" because enum does the assignments
for you.

You can also do it this way:

  local -a user i; i=( login passwd uid gid gecos home shell )
  while IFS=: read -A user
  do
    if (( ${user[$i[(i)uid]]} > 100 )) { print $user[$i[(i)login]] }
  done < /etc/passwd

Re: kinda perl split ...

[Marc Chantreux]

> You can still use "read".

wow ! and what about syntax parsing, UI and IA in zsh ? ;)
i'm impressed by zsh day by day !

regards
mc

Re: kinda perl split ...

[Bart Schaefer]

On Mar 22,  2:12pm, Marc Chantreux wrote:
}
} wow ! and what about syntax parsing, UI and IA in zsh ? ;)

IA?  Intelligent Agent?  Intel Architecture?  Intangible Assets?
Inscrutable Abbreviations?

Zsh *is* a UI.  It's not a *G*UI, but it's still a UI.

As for syntax parsing, you're welcome to become our resident expert
on zregexparse, which was added by Tanaka Akira to handle some very
complex completion definitions but never understood by anyone else.

Re: kinda perl split ...

[Marc Chantreux]

 > As for syntax parsing, you're welcome to become our resident expert
> on zregexparse, which was added by Tanaka Akira to handle some very
> complex completion definitions but never understood by anyone else.

the doc. doesn't really help for it !

zregexparse
      This implements some internals of the _regex_arguments function.

Re: kinda perl split ...

[Marc Chantreux]

Bart Schaefer wrote:

> } wow ! and what about syntax parsing, UI and IA in zsh ? ;)
> IA?  Intelligent Agent?  Intel Architecture?  Intangible Assets?
> Inscrutable Abbreviations?

sorry! AI in fact ( intelligence artificielle in french ).

> Zsh *is* a UI.  It's not a *G*UI, but it's still a UI.

you're right !