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https://issues.apache.org/jira/browse/FLINK-10216?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16593677#comment-16593677
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Timo Walther commented on FLINK-10216:
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The question is whether \{{SIMILAR TO}} and \{{REGEXP_MATCH}} would have
exactly the same semantics. Simply forwarding a regex call to Java's
implementation does not ensure any compatibility to implementations commonly
used by database vendors.
> Add REGEXP_MATCH in TableAPI and SQL
> ------------------------------------
>
> Key: FLINK-10216
> URL: https://issues.apache.org/jira/browse/FLINK-10216
> Project: Flink
> Issue Type: Sub-task
> Reporter: Juho Autio
> Priority: Major
>
> Here's a naive implementation:
> {code:java}
> public class RegexpMatchFunction extends ScalarFunction {
> // NOTE! Flink calls eval() by reflection
> public boolean eval(String value, String pattern) {
> return value != null && pattern != null && value.matches(pattern);
> }
> }
> {code}
> I wonder if there would be a way to optimize this to use
> {{Pattern.compile(value)}} and use the compiled Pattern for multiple calls
> (possibly different values, but same pattern).
> h3. Naming
> Should regex functions be prefixed with {{regexp_}} or {{regex_}}? See also:
> [https://github.com/apache/flink/pull/6448#issuecomment-415972833]
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