From: Ray Andrews <rayandrews@eastlink.ca>
To: zsh-users@zsh.org
Subject: Re: convert sed to zsh
Date: Thu, 26 Nov 2015 13:18:09 -0800 [thread overview]
Message-ID: <56577711.4050202@eastlink.ca> (raw)
In-Reply-To: <151126121744.ZM5731@torch.brasslantern.com>
On 11/26/2015 12:17 PM, Bart Schaefer wrote:
> On Nov 26, 9:49am, Ray Andrews wrote:
> } Subject: convert sed to zsh
> }
> } sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[mGK]//g"
> }
> } Here's my candidate zsh:
> }
> } bar=$foo//$'\x1B'\[([0-9](#c0,2)(;[0-9](#c0,2))#)#[mGK]/}
>
> That's a parse error, you're missing the opening curly brace.
Right. An edit-in-place error. Gotta be more careful about those they
waste people's time.
>
> You can write $'\x1B' as $'\e' for clarity.
>
> Why change {1,2} in sed to (#c0,2) in zsh? (#c1,2) should work.
I'm working from expressions taken verbatim and on faith, but that seem
to either very slightly 'disagree' with each other, or to have different
sets of codes they'll work with, or one is sightly sloppier than the
other, so I'm being careful. There could be syntax in one where no
match is acceptable, but an error in the other or some such. I know for
most things zsh just uses different symbols vis a vis regex, but there's
logic changes too so gotta be alert.
>
> } ... so far it's working, but I'm nervous about it. In another context
> } it seems I have to backslash the semi-colon, but here it seems ok either
> } way, but of course it should be one or the other.
>
> "Of course"?
I don't want to guess. If I backslash it will be because it's required.
>
> The reason both ';' and '\;' work there has to do with the properties
> of patterns rather than the properties of semicolons. Semicolon is a
> command terminator but otherwise is not special, so you need to protect
> a literal semicolon only from command parsing [such as inside $(...)].
Ah, so the backslash is acceptable but not required in the way that you
can backslash near anything.
>
> } The 'sed' is of course the kosher way (I believe) of removing color
> } codes and various other escapes like "\e[K" that seem to hang around
> } colorized output of 'grep' and so on.
>
> I'm not quite an expert on color codes but the zsh expression should
> do the same as the sed (modulo 1,2 vs. 0,2 as noted and assuming you
> have extendedglob set). I do know that there are other escapes (cursor
> movements, overstriking, etc.) that won't match this expression, but
> probably you never encounter those in the usage you expect.
Yeah, just colors, for now, anyway. I'm working from Sebastian's stuff,
which started out being able to filter colors, but not the ' \e[K' thing
that grep adds. So I added a separate filter for that, but the 'sed'
expression seems robust enough to handle that along with the color
codes. So I'm reverse engineering that back to zsh syntax. The sed
expression has an obvious robustness about it--you can see that it will
handle any color code that I know of, anyway.
Your edits in place and all good, thanks.
>
prev parent reply other threads:[~2015-11-26 21:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-26 17:49 Ray Andrews
2015-11-26 20:17 ` Bart Schaefer
2015-11-26 21:18 ` Ray Andrews [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=56577711.4050202@eastlink.ca \
--to=rayandrews@eastlink.ca \
--cc=zsh-users@zsh.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/zsh/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).