if 0 {Richard Suchenwirth 2004-07-24 - Tk's text widget has recently received an -elide feature which I hadn't tried yet. So in this weekend fun project, I experimented how to implement "folding" parts of a text content. The command elidify adds buttons in a text widget wherever an open brace appears at end of line (the typical pattern for proc bodies). If such a button displays "-", clicking it will elide (hide) the braces and its contents; clicking a "+" button will make the braces and its contents reappear. This way one can "close" details one is not interested in, and see more of the grand picture instead. }
proc elidify w {
set from 1.0
set id 0
while 1 {
set here [$w search -regexp {\{$} $from end]
if {$here eq ""} break
set n 1
while {![info complete [$w get $here "$here + $n chars"]]} {
incr n
}
set there [$w index "$here + $n chars"]
set b $w.[incr id]
button $b -text - -command "eliToggle $b" -pady 0
$w window create $here -window $b
$w tag config $b -elide 0
$w tag add $b "$here + 1 char" "$there + 1 char"
set from [$w index "$there + 2 chars"]
}
set id ;# returns the number of elidable sections
}# This procedure is called whenever a "folding" button is clicked
proc eliToggle w {
if {[$w cget -text] eq "-"} {
$w config -text +
[winfo parent $w] tag config $w -elide 1
} else {
$w config -text -
[winfo parent $w] tag config $w -elide 0
}
}if 0 {Let's now test the whole thing on its own source code:}
pack [text .t -wrap word] -fill both -expand 1 set fp [open [info script]] .t insert end [read $fp] close $fp elidify .t