syntax: fix literal extraction for 'ab??' #863
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Previously, 'ab??' returned [Complete(ab), Complete(a)], but the order matters here because of greediness. The correct result is [Complete(a), Complete(ab)]. Instead of trying to actually fix literal extraction (which is a mess), we just rewrite 'ab?' (and 'ab??') as 'ab*'. 'ab*' still produces literals in the incorrect order, i.e., [Cut(ab), Complete(a)], but since one is cut we are guaranteed that the regex engine will be called to confirm the match. In so doing, it will correctly report 'a' as a match for 'ab??' in 'ab'. Fixes #862
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Previously, 'ab??' returned [Complete(ab), Complete(a)], but the order
matters here because of greediness. The correct result is [Complete(a),
Complete(ab)].
Instead of trying to actually fix literal extraction (which is a mess),
we just rewrite 'ab?' (and 'ab??') as 'ab*'. 'ab*' still produces
literals in the incorrect order, i.e., [Cut(ab), Complete(a)], but since
one is cut we are guaranteed that the regex engine will be called to
confirm the match. In so doing, it will correctly report 'a' as a match
for 'ab??' in 'ab'.
Fixes #862