I need a pattern for a string that does not contain a specified string, while at the same time respecting the mandate to match only shortest sequences.

For example strings bracketed by [] but not containing o:

string = "[the][quick][brown][fox][jumps][over][the][lazy][dog]";

StringCases[string, x : Shortest["[" ~~ __ ~~ "]"] /; StringFreeQ[x, "o"]]
{"[the]", "[quick]", "[jumps]", "[the]", "[lazy]"}

However this is a poor solution because the pattern matcher keeps lengthening the test string rather than moving on to the next possible match, causing a tremendous slow-down on longer strings. Illustrated:


StringCases[string, x : Shortest["[" ~~ __ ~~ "]"] /; StringFreeQ[Echo@x, "o"]]









. . .

What I actually want can be accomplished with a second filtering operation:

StringCases[string, "[" ~~ Shortest[__] ~~ "]"];

Pick[%, StringFreeQ[%, "o"]]
{"[the]", "[quick]", "[jumps]", "[the]", "[lazy]"}

I would prefer to do this in a single pass.

A solution in the case of a single-character string to prohibit is Except:

StringCases[string, "[" ~~ Shortest[Except["o"] ..] ~~ "]"]
{"[the]", "[quick]", "[jumps]", "[the]", "[lazy]"}

At least in Mathematica 10.1 Except does not work with more than one character:

StringCases[string, "[" ~~ Shortest[Except["ox"] ..] ~~ "]"]

StringExpression::invld: Element Shortest[Except[ox]..] is not a valid string or pattern element in [~~Shortest[Except[ox]..]~~]. >>

In actuality my delimiters are multicharacter as well so I cannot get around this with something like Except["]"] .. either.

Is there another approach that is fast and doesn't require a second filtering pass in one form or another?