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Is there a performance problem when using non-greedy regular expressions and match variables on long strings? See output and code below. Tested on Win/XP (Tcl 8.4.13 & 8.5.7) and FreeBSD (Tcl 8.4.13).

The time shown is when the match encompasses the whole buffer.

If match variables are _not_ used then there is no performance problem with non-greedy matching! Seems strange that just because the regexp has match vars then the performance goes down the tubes.

Has anyone come across this before and discovered a solution?
I'm the verge of going back to using greedy reg exps and iterating backwards through each match to simulate the non-greedy matching (I can do this because of the patterns of match var I am looking for)

Output from script :
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71640
start regexp
end regexp - non greedy, with matchVar 29677 millis
end regexp - non greedy, no matchVar 0 millis
end regexp - greedy, with matchVar 5 millis
end regexp - greedy, no matchVar 0 millis

= = =

Here is the script:
= = =

puts [string length $longString]

puts "start regexp"

set now [clock clicks]
regexp (.*?)($reTerminator) $longString wholeMatch message terminator
puts "end regexp - non greedy, with matchVar [expr ([clock clicks] - $now) / 1000 ] millis"

set now [clock clicks]
regexp (.*?)($reTerminator) $longString
puts "end regexp - non greedy, no matchVar [expr ([clock clicks] - $now) / 1000 ] millis"

set now [clock clicks]
regexp (.*)($reTerminator) $longString wholeMatch message terminator
puts "end regexp - greedy, with matchVar [expr ([clock clicks] - $now) / 1000 ] millis"

set now [clock clicks]
regexp (.*)($reTerminator) $longString
puts "end regexp - greedy, no matchVar [expr ([clock clicks] - $now) / 1000 ] millis"

= = =