New-line in prompt

New-line in prompt

[Owen M. Astley]

I am trying to get a new line (\n) in a prompt (actually I only want the
new line if the current one is too long).  Has anybody got any idea about
how to do this?  %{\n%} works but, as the man page says, it shouldn't
change the cursor position (for obvious reasons if you use it).

Thanks, Owen

Re: New-line in prompt

[Phil Pennock]

Typing away merrily, Owen M. Astley produced the immortal words:
> I am trying to get a new line (\n) in a prompt (actually I only want the
> new line if the current one is too long).  Has anybody got any idea about
> how to do this?  %{\n%} works but, as the man page says, it shouldn't
> change the cursor position (for obvious reasons if you use it).

How about using a print in the precmd special function?
If you want the normal prompt escapes in it, use the -P option to print.
precmd is called before every prompt.

% function precmd { print -P Funky-%~ }
Funky-~
% echo

Funky-~
% cd /usr
Funky-/usr
% 

Hope this helps.
-- 
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Re: New-line in prompt

[Bart Schaefer]

On Nov 9,  1:27pm, Owen M. Astley wrote:
} Subject: New-line in prompt
}
} I am trying to get a new line (\n) in a prompt (actually I only want the
} new line if the current one is too long).  Has anybody got any idea about
} how to do this?  %{\n%} works but, as the man page says, it shouldn't
} change the cursor position (for obvious reasons if you use it).

This has spawned a discussion on zsh-workers that I thought I'd let the
zsh-users know about.

(1) Putting a newline in the prompt is a FAQ; the short answer is, you
just quote it:

PS1='stuff before the newline
stuff after the newline'

(2) A patch for 3.1.5 has been posted to add a "line length" test to the
conditional prompt syntax.  Without that patch, there's no simple way to
accomplish "insert Y if the prompt so far is longer than X characters."

Here's a not-so-simple way, but note that it fails if you have an non-
printing characters in the prompt (escapes for bold and underline, or
anything in %{...%}, etc.).

precmd() {
    # ... whatever you now have in precmd, followed by:
    fold-prompt
}

# Don't set PROMPT or PS1, instead set this array:
parts_of_PS1=(%m %n "%~" "%#")		# For example

fold-prompt() {
    emulate -R zsh
    setopt localoptions
    local tmp_PS1="" p P
    local fold_at=$[$COLUMNS-1]		# Adjust to taste

    for p in $parts_of_PS1
    do
	P=$(print -nP $p)
	if [[ $[$#tmp_PS1+$#P] -lt $fold_at ]]
	then
	    tmp_PS1="${tmp_PS1:+$tmp_PS1 }$P"
	else
	    ((fold_at += $#tmp_PS1 + 1))
	    tmp_PS1="$tmp_PS1
$P" # Note, newline enclosed in quotes ending on this line
	fi
    done
    PS1="${tmp_PS1:gs/%/%%/} "
}

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com