olemus
määratletud tähistuse ja ehitusega avaldis
otsitava teksti malli ja käsitlusviisi spetsifitseerimiseks

ISO/IEC/IEEE 9945:
mall spetsiifiliste stringide valimiseks
mingist märgistringide kogumist
= a pattern that selects specific strings
from a set of character strings

ülevaateid
https://cizixs.com/2013/07/29/basic-regular-expression/

https://www.regular-expressions.info/quickstart.html

http://www.regular-expressions.info/tutorial.html

https://en.wikipedia.org/wiki/Regular_expression

http://web.mit.edu/hackl/www/lab/turkshop/slides/regex-cheatsheet.pdf

https://doc.lagout.org/programmation/Regular%20Expressions/Mastering%20Regular%20Expressions_%20Understand%20Your%20Data%20and%20Be%20More%20Productive%20%283rd%20ed.%29%20%5BFriedl%202006-08-18%5D.pdf