Re: Belaboring substitution syntax

[Ray Andrews <rayandrews@eastlink.ca>]

On 2022-11-17 00:59, Roman Perepelitsa wrote:
> ...
> And these four are equivalent:
>
>      ${array[@]}
>      ${(@)array}
>      ${array}
>      $array
>
> Roman.

Thanks, that's what I call quality explanation, I'm going to save that 
whole post to my cheat sheet and work it over at length.  2/3 of my own 
difficulties here involve all this splitting/joining stuff. Mostly 
because I use Sebastian's n_list() quite a bit and it demands 
lines/elements for input, with blank lines and spaces in filenames 
protected.  The construction that seems robust is like this:

n_list "${array[@]}"

... for the reasons you mention.  A useful document would be the 
Unabridged Guide to Zsh Arrays (their splitting, splicing, slicing and 
dicing, with protections and without, with all flags explained and 
specimens of every possible syntax and when you'd want to use them).

I know it's far too late in the game to even think about fundamental 
changes, but if we had to do it all over again I'd advocate for a single 
universal expansion grammar:

${(CONTROL) FIELD  /  FIELD / FIELD }

No '//' '##' '%%' or any of that.  '/' is the universal separator, and 
what is done to the fields is entirely explained within the 
parenthesis.  No more worries about special characters except '/' and 
maybe " " and ' ' and backslash cuz those expansion controls are 
robust.  Within the parenthesis there are zero worries about literals, 
it's 100% operators so the syntax-space is unlimited.  Within the fields 
there are zero operators (except quote expansions) so parsing becomes 
vastly simpler.

${(S:a!$%&@N/(xx^)**/*<>) ${array} / ${filter} }

... what's in the () explains exactly what is to be done vis a vis the 
two fields ... or more.

${(VERBS) NOUNS / NOUNS / NOUNS }

${(PREDICATES) SUBJECTS } ... that's the way a grammar should look.  
Basically 'flags' do everything and verbs and nouns are never 
intermingled.  That's the reason glob qualifiers are so stinking 
powerful, cuz within the parenthesis their is nothing one might not 
achieve.

Nevermind.  :-)