Add support to string functions

[wiikviz]

• [x] ascii(e: String): String
• [x] base64(e: String): String
• [x] concat(exprs: String*): String
• [x] concat_ws(sep: String, exprs: String*): String
• [ ] decode(value: String, charset: String): String
• [ ] encode(value: String, charset: String): String
• [ ] format_number(x: String, scale: Int | fmt: String): String
• [ ] format_string(format: String, arguments: String*): String
• [ ] initcap(e: String): String
• [x] instr(str: String, substring: String): String
• [x] length(e: String): String
• [x] lower(e: String): String
• [ ] levenshtein ( l : String , r : String ) : String
• [ ] locate(substr: String, str: String): String
• [ ] locate(substr: String, str: String, pos: Int): String
• [ ] lpad(str: String, len: Int, pad: String): String
• [ ] ltrim(e: String): String
• [x] regexp_extract(e: String, exp: String, groupIdx: Int): String
• [x] regexp_replace(e: String, pattern: String, replacement: String): String
• [x] regexp_replace(e: String, pattern: String, replacement: String): String
• [ ] unbase64(e: String): String
• [ ] rpad(str: String, len: Int, pad: String): String
• [ ] repeat(str: String, n: Int): String
• [ ] rtrim(e: String): String
• [ ] rtrim(e: String, trimString: String): String
• [ ] soundex(e: String): String
• [x] split(str: String, regex: String): String
• [ ] split(str: String, regex: String, limit: Int): String
• [ ] substring(str: String, pos: Int, len: Int): String
• [ ] substring_index(str: String, delim: String, count: Int): String
• [ ] overlay(src: String, replaceString: String, pos: Int, len: Int): String
• [ ] overlay(src: String, replaceString: String, pos: Int): String
• [ ] translate(src: String, matchingString: String, replaceString: String): String
• [x] trim(e: String): String
• [ ] trim(e: String, trimString: String): String
• [x] upper(e: String): String

https://sparkbyexamples.com/spark/usage-of-spark-sql-string-functions/

[wiikviz]

Arguments expr: An expression that evaluates to a numeric. scale: An INTEGER expression greater or equal to 0. fmt: A STRING expression specifying a format.

SELECT format_number(12332.123456, 4); 12,332.1235 SELECT format_number(12332.123456, '#.###'); 12332.123 SELECT format_number(12332.123456, 'EUR ,###.-'); EUR 12,332.- https://learn.microsoft.com/en-us/azure/databricks/spark/latest/spark-sql/language-manual/functions/format_number

[mihan1235]

Were added new functions

1. startsWith(string,string) --> bool
2. endsWith(string, string) --> bool
3. isEmpty(string) --> bool
4. nonEmpty(string) --> bool
5. findFirstIn(string, regex) --> null || string
6. findAllIn(string,regex) --> array of strings
7. replaceAllIn(string, regex, string) --> string
8. replaceFirstIn(string, regex, string) --> string
9. split(string, regex) --> array of strings
10. toLowerCase(string) --> string
11. toUpperCase(string) --> string
12. trim(string) --> string