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| -rw-r--r-- | txr.1 | 8 |
1 files changed, 4 insertions, 4 deletions
@@ -2883,12 +2883,12 @@ in mind this relationship between regular expressions and sets in understanding intersection and complement. Given a finite set of strings, like the set { "abc", "def" }, which corresponds -to the regular expression (abc|def), the complement is set which contains an -infinite number of strings: it consists of all possible strings except "abc" +to the regular expression (abc|def), the complement is the set which contains +an infinite number of strings: it consists of all possible strings except "abc" and "def". It includes the empty string, all strings of length 1, all strings of length 2, all strings of length 3 other than "abc" and "def", all strings of -length 4, etc. This means that a "harmless looking" expression like -~(abc|def) can actually match arbitrarily long inputs. +length 4, etc. This means that a "harmless looking" expression like ~(abc|def) +can actually match arbitrarily long inputs. .SS Set Difference |