# Here's the tcl loop for scanning a text widget for  a  pattern.   At
# every match, the script is run with the "first" and "last" marks set
# to delimit the matched string.

proc forAllMatches {w pattern script} {
	scan [$w index end] %d numLines
	for {set i 1} {$i < $numLines} {incr i} {
		$w mark set last $i.0
		while {[regexp -nocase -indices $pattern [$w get last "last lineend"] indices]} {
			$w mark set first "last + [lindex $indices 0] chars"
			$w mark set last  "last + 1 chars + [lindex $indices 1] chars"
			uplevel $script
		}
	}
}