Function interp_lines_grob 

fn interp_lines_grob(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Create a lines grob object without drawing it.

@param x,y positions (unit or numeric) @param gp graphical parameters @param name unique grob name @param vp viewport @return a lines grob object @namespace grid