Implement forward, back, and go.

diff --git a/help.tcl b/help.tcl
index a7267f2cbfa9eff641cc0bdee04501a7208ce8b7..eb2e4498bdd3687cbed7c498d68e474587dd1091 100644 (file)
--- a/help.tcl
+++ b/help.tcl
@@ -2,19 +2,30 @@
 # $Id$
 #
 
-lappend auto_path /usr/local/lib/stl
-
 dialog help_window {
     param topics {}
     param width 50
     param height 35
     param helpdir .
+    member history {}
+    member history_ndx -1
+    member history_len 0
     method create {} {
        frame $self.menu -relief raised -bd 2
        menubutton $self.menu.topics -text "Topics" -underline 0 \
            -menu $self.menu.topics.m
        pack $self.menu.topics -in $self.menu -side left
        set m [menu $self.menu.topics.m]
+       menubutton $self.menu.navigate -text "Navigate" -underline 0 \
+           -menu $self.menu.navigate.m
+       pack $self.menu.navigate -in $self.menu -side left
+       set m [menu $self.menu.navigate.m]
+       $m add command -label "Forward" -underline 0 -state disabled \
+           -command "$self forward"
+       $m add command -label "Back" -underline 0 -state disabled \
+           -command "$self back"
+       $m add cascade -label "Go" -underline 0 -menu $m.go
+       menu $m.go -postcommand "$self fill_go_menu"
        frame $self.text -bd 2 -relief raised
        scrollbar $self.text.sb -command "$self.text.t yview"
        text $self.text.t -relief sunken -bd 2 -yscroll "$self.text.sb set" \
@@ -40,15 +51,20 @@ dialog help_window {
        $self.text.t config -width $slot(width) -height $slot(height)
     }
     method show_topic {topic} {
-       set slot(topic) $topic
+       incr slot(history_ndx)
+       set slot(history) [lrange $slot(history) 0 $slot(history_ndx)]
+       set slot(history_len) [expr $slot(history_ndx) + 1]
+       lappend slot(history) $topic
        $self read_topic $topic
-       wm title $self "Help: $topic"
     }
     method read_topic {topic} {
+       set slot(topic) $topic
+       wm title $self "Help: $topic"
        set f [open $slot(helpdir)/$topic.html r]
        set txt [read $f]
        close $f
-       feedback .help_feedback -steps [set slot(len) [string length $txt]]
+       feedback .help_feedback -steps [set slot(len) [string length $txt]] \
+           -title "Rendering HTML"
        set slot(remaining) $slot(len)
        grab set .help_feedback
        tkhtml_set_render_hook "$self update_feedback"
@@ -56,9 +72,37 @@ dialog help_window {
        tkhtml_render $self.text.t $txt
        grab release .help_feedback
        destroy .help_feedback
+       set m $self.menu.navigate.m
+       if {($slot(history_ndx)+1) < $slot(history_len)} {
+           $m entryconfig 1 -state normal
+       } else {
+           $m entryconfig 1 -state disabled
+       }
+       if {$slot(history_ndx) > 0} {
+           $m entryconfig 2 -state normal
+       } else {
+           $m entryconfig 2 -state disabled
+       }
     }
     method follow_link {link} {
-       $self read_topic [file root $link]
+       $self show_topic [file root $link]
+    }
+    method forward {} {
+       incr slot(history_ndx)
+       $self read_topic [lindex $slot(history) $slot(history_ndx)]
+    }
+    method back {} {
+       incr slot(history_ndx) -1
+       $self read_topic [lindex $slot(history) $slot(history_ndx)]
+    }
+    method fill_go_menu {} {
+       set m $self.menu.navigate.m.go
+       catch {$m delete 0 last}
+       for {set i [expr [llength $slot(history)]-1]} {$i >= 0} {incr i -1} {
+           set topic [lindex $slot(history) $i]
+           $m add command -label $topic \
+               -command [list $self show_topic $topic]
+       }
     }
     method update_feedback {n} {
        if {($slot(remaining) - $n) > .1*$slot(len)} {