Re: [9fans] Non-parallel loop in Sam

["Rob Pike" <robpike@gmail.com>]

 , | tail -r
is simpler.

-rob

On Thu, Feb 7, 2008 at 8:55 PM, Douglas A. Gwyn <DAGwyn@null.net> wrote:
> > My question is, how to
>  > impliment non-parallel loop/condition commands in Sam?
>
>  As you noticed, it's a different model from ed, sed, etc.
>  In sam, you can specify sequential edits on separate lines,
>  and a collection of lines can be grouped into a single action
>  by surrounding the lines with braces { }.
>
>
>  > In another
>  > word, how to do things, such as inverse all lines, in Sam
>
>  Don't forget that you have a lot of text-oriented tools at
>  your disposal in any Unix or Plan 9 environment.  To
>  reverse the order of lines within a file already opened by
>  sam, I would simply enter the following sam commands:
>         ,| nl | sort -rn
>         ,x/^ +[0-9]+    /d
>  (on Solaris; maybe a slight change would be needed on Plan 9).
>  This would be better packaged as a shell script, using sed
>  rather than sam for the final number-stripping operation.
>  You could then merely invoke that script for whatever "dot"
>  region is selected in sam:
>         | reverse       # the script name
>  It is nice to build up a little collection of useful
>  editing scripts.  Sometimes it is useful to enter nroff
>  source and pipe it through nroff for automatic formatting:
>         unformatted text
>         .pl 12p\"prevent spacing to end of page afterward
>         .ll 2i
>         .tl 'le'ctr'ri'
>         .ce
>         centered title
>         formatted text
>         unformatted text
>  Highlight (set dot to) all but the "unformatted text" and
>  enter the same command
>         | nroff -Tlp
>  (on Solaris; for Plan 9 -Tlp is probably different).  The
>  -ms or other nroff macro package could be used, as desired.
>