main.c: remove a FIXME

[emanuele6]

Using an "invalid" variable name is fine, it just means you will only be
able to access that argument from $ARGS.named

[wader]

Huh didn't know. Help says --arg name value set $name to the string value; so maybe we should check?

[emanuele6]

I don't see the point in restring that; jq -n ... '$ARGS.named' is a fairly common pattern to construct objects from some shell variables; e.g.

jq -n \
    --arg foo "$(something "$baz")" \
    --arg bar "$thisthing" \
    '$ARGS.named'

We would be preventing users from constructing objects with this-cool-key using this method; it is likely that there are scripts that already rely on this.

Maybe the --help description could be extended? (Wouldn't that take too much space?)

The man page entry for --arg (but only the one for --arg even though it also works with --argjson, --slurpfile, etc) mentions that the arguments are also available in the $ARGS.named object, but does not say anything about $name only being assigned if name is a valid identifer

--arg name value:

    This option passes a value to the jq program as a predefined
    variable. If you run jq with --arg foo bar, then $foo is available
    in the program and has the value "bar". Note that value will be
    treated as a string, so --arg foo 123 will bind $foo to "123".

    Named arguments are also available to the jq program as
    $ARGS.named.

[wader]

Good points, yeap maybe enough to add some note about it in the more detailed arg docs?