xidel: is it possible to declare a variable for a XPath expression?

Question

Like

xmlstarlet sel --var xp 'xpathExpression' -t -v '$xp' file.xml

is it possible to use internal variables in xidel?

I know I can use shell and "double quotes", but that's not the question.

Answer 1

readme, or xidel --usage:

Variable assignment:                                         $var := value

  adds $var to a set of global variables, which can be created and accessed everywhere.
  (Xidel prints the value of all variables to stdout, unless you use the --extract-exclude option)

So, for instance:

$ xidel -se 'var:="bar"' -e '"foo"||$var'
var := bar
foobar

$ xidel -s --extract-exclude=var -e 'var:="bar"' -e '"foo"||$var'
foobar

Or of course with the XQuery Let Clause (not global):

$ xidel -se 'let $var:="bar" return "foo"||$var'
foobar

---

xidel --help:

--variable=<string>    Declares a variable (value taken from environment if not
                       given explicitely) (multiple variables are preliminary)

So, for instance:

$ xidel -s --variable="var=bar" -e '"foo"||$var'
$ xidel -s --variable var=bar -e '"foo"||$var'
foobar