hide lines from view

[Yakov Lerner]

Hello,

How do I hide first N lines of the file from view (like, using folds
maybe ?).

Even better, I want to hide, out of N first lines of file, those
lines that match some pattern.

Even better, how do I have vim show some 1-liner string (coming
from the vim script) to show in place of the hidden lines ? (I am not
dure this last item is possible, but I think the first two items
are possible using folds.)

Thanks
Yakov
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[Tim Chase-2]

> How do I hide first N lines of the file from view (like, using
> folds maybe ?).

Yes, using folds is likely the way to do what you want.

in Ex mode (assuming N is 20)

        :1,20fold

in Normal mode

        ggzf20G

> Even better, I want to hide, out of N first lines of file,
> those lines that match some pattern.

Do you just want to hide select lines in the range 1..N, or do
you want to hide lines 1..N where N is found by a pattern?  If
it's the latter you can do:

in Ex mode

        :1;/pattern/fold

in Normal mode

        ggzf/pattern

> Even better, how do I have vim show some 1-liner string
> (coming from the vim script) to show in place of the hidden
> lines ? (I am not dure this last item is possible, but I think
> the first two items are possible using folds.)

Folding shows condenses multiple lines into a single
"placeholder" line as you describe.  Getting different behavior
would actually be more work :)

For more information, check out

        :help :fold
        :he zf
        :he gg
        :he G

Hope this gives you what you were looking for,

-tim

[Gary Johnson]

Here's another approach, using fold expressions instead of manual
folds.  First,

    :set foldmethod=expr
    :set foldlevel=0

On 2005-11-16, [hidden email] wrote:

> How do I hide first N lines of the file from view (like, using folds
> maybe ?).

For example, let N = 20.

    :set foldexpr=v:lnum<=20

> Even better, I want to hide, out of N first lines of file, those
> lines that match some pattern.

    :set foldexpr=v:lnum<=20&&getline(v:lnum)=~'pattern'

> Even better, how do I have vim show some 1-liner string (coming
> from the vim script) to show in place of the hidden lines ? (I am not
> dure this last item is possible, but I think the first two items
> are possible using folds.)

This really depends on what you want your 1-liner string to be.  It
can be set via the 'foldtext' option.  As an example:

    :set foldtext=MyFoldText()

    :function MyFoldText()
    :   let n = v:foldend - v:foldstart + 1
    :   return 'This is a fold of ' . n . ' lines'
    :endfunction

See

    :help usr_28.txt
    :help fold.txt

HTH,
Gary

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Gary Johnson                 | Agilent Technologies
[hidden email]     | Wireless Division
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