[LUCENE-8812] add KoreanNumberFilter to Nori(Korean) Analyzer

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 9.0, 8.2
• Lucene Fields: New
• Assignee: Namgyu Kim
• Reporter: Namgyu Kim
• Created: 24/May/19 15:12
• Updated: 28/Aug/22 15:45
• Resolved: 12/Jun/19 16:39

Description

This is a follow-up issue to LUCENE-8784.

The KoreanNumberFilter is a TokenFilter that normalizes Korean numbers to regular Arabic decimal numbers in half-width characters.

Logic is similar to JapaneseNumberFilter.
It should be able to cover the following test cases.

1) Korean Word to Number
십만이천오백 => 102500

2) 1 character conversion
일영영영 => 1000

3) Decimal Point Calculation
3.2천 => 3200

4) Comma between three digits
4,647.0010 => 4647.001

Issue Links

• is related to: LUCENE-8784 Nori(Korean) tokenizer removes the decimal point.