When are sequences too much ?

I'm struggling with (one of many) artifacts of allowing expressions (variables, and positional parameters) be XdmValues, which allow sequences.

In generally this is a good, if not necessary thing.

It allows sequences to be stored in variables and produced as expressions and be preserved as sequences. For example

A=<[ 1 , 2 , ]>

xquery -f file.query -v sequence_var $A

Note that you can pass a single XdmValue ($A) as a parameter to Xquery.

The problem comes if you want to 'flatten' the sequence to seperate positional params.

Example

A=$(ls) # produces a single sequence of files

echo $A

This looks right but under the hood echo is getting a single argument (argv[1]) which is a sequence.

Suppose I want to delete all these files

posix:rm $A

Ups ... rm now gets 1 argument ... it has to know that if the argument is sequence to iterate over each item like this

for i in $A ; do posix:rm $i ; done

For many commands getting sequences where they expect items is problematic.

But on the other hand being able to preserve sequences is critical.

So What to do ?
I'm working on (and open to suggestion) a syntax which forcibly flattens sequences into positional parameters.

Something like maybe

$-variable

although I'd like it to work with inline expressions as well

posix:rm $(ls) # How to get this to flatten ?

Comments welcome on this idea