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| _Expressions_ |
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| # Regular expressions |
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| The `=~` and `!~` operators can be used to check against regular expressions. |
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| The expression `a =~ b` is true if `a` matches `b`, while |
| `a !~ b` is true if `a` does _not_ match `b`. |
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| Just as with comparison operators, these operators maybe be used |
| as unary versions to define a set of strings. |
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| <!-- CUE editor --> |
| _regexp.cue:_ |
| ``` |
| a: "foo bar" =~ "foo [a-z]{3}" |
| b: "maze" !~ "^[a-z]{3}$" |
| |
| c: =~"^[a-z]{3}$" // any string with lowercase ASCII of length 3 |
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| d: c |
| d: "foo" |
| |
| e: c |
| e: "foo bar" |
| ``` |
| |
| <!-- result --> |
| `$ cue eval -i regexp.cue` |
| ``` |
| a: true |
| b: true |
| c: =~"^[a-z]{3}$" |
| d: "foo" |
| e: _|_ /* invalid value "foo bar" (does not match =~"^[a-z]{3}$") */ |
| ``` |
