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Re: Belaboring substitution syntax

On 2022-11-17 00:59, Roman Perepelitsa wrote:
And these four are equivalent:



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:


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.


${(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.  :-)

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