Re: convolutions

[Ray Andrews <rayandrews@eastlink.ca>]

On 11/06/2015 09:38 PM, Bart Schaefer wrote:
> On Fri, Nov 6, 2015 at 6:15 PM, Ray Andrews <rayandrews@eastlink.ca> wrote:
>> Gentlemen:
>>
>>      echo "$(eval echo "\${$(cat in_file)}")" >! out_file
>>
>> That's the best I've been able to do expanding color variables, eg. " ${red}
>> " into their native " \e[31;1m " in a file.
> Just as an aside, this is the second code example you've posted
> recently that can't possibly work in practice.  I can only assume
> you're mis-transcribing in an attempt to simplify whatever your real
> code is.
>
I did indeed edit it a bit.  Here's the pasted actual test file:



test2 ()
{
     echo "$(eval echo "\${$(cat junk1)}")" >! junk2
     cat junk2
}

... which works as advertised.
> If I understand this correctly, you have a file that contains text
> which looks like
>
>     The following ${fg[red]}text is red${reset_color} and this is not
>
> and you want to end up with the variables expanded in out_file as the
> actual escape sequences?
>
>      print -R "${(e)$(<in_file)}" >| out_file

Does the trick, thanks, it's no shorter, but much more respectable. 
print has many tricks up it's sleeve.
>
> Of course that will also replace other possible expansions that may
> appear in the text of in_file.  If you really want to replace exactly
> and only the specific references to color variables, you needs
> something like Zyx's sed expression.
Yeah, my snippet would have the same issue so that's fine.  It seems so 
laborious tho.  Too bad there wasn't some way of forcing expansions in a 
prescribed order to avoid the echoing and evaling.
>