Coral transform hive function “regexp_extract” to trino by introduce a new function "hive_pattern_to_trino"

[gjhkael]

Coral transform the following hive sql to trino

select regexp_extract('1a 2b 14m', '\d+', 1); 

result:

select regexp_extract('1a 2b 14m', "hive_pattern_to_presto"('\d+'), 1); 

But trino not have the function name of "hive_pattern_to_presto", then the query will failed with exception:

Function 'hive_pattern_to_trino' not registered

So, why you introduce the "hive_pattern_to_trino" function? Do this function is implement in linkedin internal?

[findinpath]

Related code:

coral/coral-trino/src/main/java/com/linkedin/coral/trino/rel2trino/UDFTransformer.java

Lines 147 to 149 in c964563

	OP_MAP.put("hive_pattern_to_trino",
	new SqlUserDefinedFunction(new SqlIdentifier("hive_pattern_to_trino", SqlParserPos.ZERO),
	FunctionReturnTypes.STRING, null, OperandTypes.STRING, null, null));