set threadinfo [cacheThreadinfo $urec $group $upto]
    dict with threadinfo {}

    set first [lindex $hdrs 0]
    set last [lindex $hdrs end-1]

    update_last $user $group $last

    html {
<table style='table-layout: fixed; width:100%;' >
<colgroup>
<col style='width: 60%;' />
<col style='width: 20%;' />
<col style='width: 10%;' />

    }

    html "</form>\n"

    return $html
}

# Update number of the last article when user previously read this group
proc update_last {user group last} {
    # Article numbers after the ugrp old_last value will be considered new.
    # If the ugrp record does not already have a new_last value, set it.
    set ugrp [redis hget "ugrp $user" $group]
    lassign $ugrp old_last new_last
    if {$new_last eq {} && $last ne {}} {
        redis hset "ugrp $user" $group [list $old_last $last]
    }

}

# Reverse the display order of threads in a group
proc reverse_group {sock urec group} {
    lassign $urec user can_post params

    set reverse [dict get $params rev]

<table style='table-layout: fixed; width:100%; border-collapse:collapse' >
}
    set indent 0
    set prev_ind $indent
    foreach {num indent} $thread {
        if {$indent < $prev_ind} {
            html {<tr style='height:6px'>} \
	        "<td colspan='[expr {max(30-1-$indent,1)}]' class='rb'></td>" \
	        [string repeat {<td class='r'></td>} [expr {$indent+1}]] "</tr>\n"
	}

        set frag " id='a$num'"
        set clas rbl
        if {$num == $target} {
            append clas { sel}

        if {$rot13} {
            set line [rot13 $line]
	}
        if {$markup} {
            html "[markup_art_line $line]\n"
        } else {
	    # make URLs clickable, encode <>
	    set url_re {https?://[[:alnum:]\-;,/?:@&=+$_.!~*()#%]+}
	    set line [regsub -all $url_re $line "\x01&\x02"]
	    set line [enpre $line]
	    set line [regsub -all {\x01([[:graph:]]+)\x02} $line {<a href='\1' target='_blank'>\1</a>}]
            html "$line\n"
        }
        if {$reflow} {
            html "<br/>"
        }
    }
    if {! $reflow} {html "</pre>\n"}
    return $html
}

# Convert one article line to html
# (might I be overthinking this?)
proc markup_art_line line {
    # First tokenise line into a list of triples:
    # text before the token, token type, text of the token.
    # Token types are url, begin-emphasis, end-emphasis.
    set url_re {(https?://[[:alnum:]\-;,/?:@&=+$_.!~*()#%]+)}
    set begin_emp_re {(?:(?:\A|\s)([*/_]+)[[:alnum:]])}
    set end_emp_re {(?:[[:alnum:]]([*/_]+)(?:\Z|\s))}
    set re "$url_re|$begin_emp_re|$end_emp_re"
    set indices [regexp -indices -all -inline -- $re $line]
    set start 0
    set ::tokens {}
    foreach {all url be ee} $indices {

}

# Save user's preferences
proc save_prefs {urec sock} {
    lassign $urec user can_post
    upvar #0 Httpd$sock data
    set query [Url_DecodeQuery $data(query)]
    # Check colour settings are not something dodgy
    foreach field {gen_bg gen_fg new_bg new_fg rep_bg rep_fg sel_bg sel_fg quo_bg quo_fg} {
        if {[regexp {[^[:alnum:]#]} [dict getdef $query $field {}]]} { 
	    return "<br/><em>Save failed: bad data in '$field'.</em>"
	}
    }
    foreach field {blocks groups} {
        if {! [dict exists $query $field]} {
	    return "<br/><em>Save failed: '$field' missing.</em>"
	}
        set $field [string trim [dict get $query $field]]
        dict unset query $field
    }