How to separate string into shell arguments?

Question

I have this test variable in ZSH:

test_str='echo "a \" b c"'

I'd like to parse this into an array of two strings ("echo" "a \" b c").

i.e. Read test_str as the shell itself would and give me back an array of arguments.

Please note that I'm not looking to split on white space or anything like that. This is really about parsing arbitrarily complex strings into shell arguments.

Answer 1

Zsh has (z) modifier:

ARGS=( ${(z)test_str} )

. But this will produce echo and "a \" b c", it won’t unquote string. To unquote you have to use Q modifier:

ARGS=( ${(Q)${(z)test_str}} )

: results in having echo and a " b c in $ARGS array. Neither would execute code in … or $(…), but (z) will split $(false true) into one argument.

that is to say:

% testfoo=${(z):-'blah $(false true)'}; echo $testfoo[2]
$(false true)