@Incubating class RegexChecker extends TypeCheckingDSL
Checks at compile-time for cases of invalid regex usage where the actual regex string can be identified (e.g. inline or defined by a local variable with an initial value or a field with an initial value). A number of errors which would normally surface only at runtime are handled.
Pattern#compile
method:
~/\w{3/ // missing closing repetition quantifier brace ~"(.)o(.*" // missing closing group bracket Pattern.compile(/?/) // dangling meta character '?' (Java longhand)These examples illustrate explicitly defined constant strings but local variable or field definitions where a constant string can be determined are also checked.
Pattern#matches
method:
'foobar' =~ /f[o]{2/ // missing closing repetition quantifier brace 'foobar' ==~ /(foo/ // missing closing group bracket Pattern.matches(/?/, 'foo') // dangling meta character '?' (Java longhand)
def m = 'foobar' =~ /(...)(...)/ assert m[0][1] == 'foo' // okay assert m[0][3] // type error: only two groups in regexAnd similarly for Java long-hand variants:
Pattern p = Pattern.compile('(...)(...)') Matcher m = p.matcher('foobar') assert m.find() assert m.group(1) == 'foo' // okay assert m.group(3) // type error: only two groups in regex
matcher[0]
, the getAt
extension method for Matcher
is called. This may return a String (if no groups occur within the regex) or a list of String values
if grouping is used, hence the declared return type of the mentioned getAt
method is Object
to account for these two possibilities. When using RegexChecker
, the inferred type will be either
String
or List<String>
when a regex string can be identified.
Over time, the idea would be to support more cases as per:
https://checkerframework.org/manual/#regex-checker
https://homes.cs.washington.edu/~mernst/pubs/regex-types-ftfjp2012.pdf
https://github.com/typetools/checker-framework/tree/master/checker/src/main/java/org/checkerframework/checker/regex
Modifiers | Name | Description |
---|---|---|
class |
RegexChecker.1 |
|
class |
RegexChecker.2 |
Constructor and description |
---|
RegexChecker() |
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