Unexpected template-style behavior with `default`

[xpe]

First, thanks for sigil. I prefer it already to envsubst and shell evaluation.

% print "{{ \$x | default \"foo\" }}" | tee template
{{ $x | default "foo" }}

This did not behave as I expected:

% sigil -f template
template: template:1: undefined variable "$x"

Interestingly, in this case, the default works:

% sigil -f template x=
foo

Regular behavior, of course, is fine:

% sigil -f template x=bar
bar

I'm using sigil 0.6.0 on macOS.

Now, after reading how Hugo does templating, I tried using $.x instead of $x, and...

% print "{{ \$.x | default \"foo\" }}" | tee template
{{ $.x | default "foo" }}
% sigil -f template
foo

Ok, this is the result I wanted, but it took a lot of horsing around.

At the least, I'd suggest more documentation.