Re: upvar and uplevel - help

It is a rather silly example, but the secret is that you pass the *name*
of the variables and not the value.

I have refactored the 'render' proc to use 'upvar' and this is turning out to be
more useful in simplifying all 'components',
```
proc render {data css template} {
    upvar $data _data
    upvar $css _css
    upvar $template _template
    # Generate scoped CSS and get container class
    lassign [scope_css $_css] scoped_css container_class
   
    # Create a container with the scoped CSS
    set result [div [list class $container_class] \
    [style {} $scoped_css] \
    [eval $_template]]
    return $result
}
```
as an example here is 'pagination' component,
```
...
    dict set data headers {Name Email Status {Last Active}}
    set page 1  ;# Current page (default to 1)
    set page_size 5  ;# Rows per page

    set template {
upvar page _page
upvar page_size _page_size
table {class "pagination-table"} \
    [tr {} \
{*}[lmap header [dict get $_data headers] {
     th {} $header
}]] \
    {*}[lmap row [lrange [dict get $_data rows] [expr {($_page - 1) * $_page_size}] [expr {$_page * $_page_size - 1}]] {
tr {} \
    {*}[lmap cell $row {
td {} $cell
    }]
    }] \
    [div {class "pagination-nav"} \
[if {$_page > 1} {
     a [list href "/pagination?page=[expr {$_page - 1}]" rel "prev"] "Previous"
}] \
[span {} "Page $_page"] \
[if {$_page * $_page_size < [llength [dict get $_data rows]]} {
     a [list href "/pagination?page=[expr {$_page + 1}]" rel "next"] "Next"
}]]
    }
    return [render data table_pa_styles template]
}
```