Is “regex” in modern programming languages really “context sensitive grammar”?

Question

Over the years, \"regex\" pattern matching has been getting more and more powerful to the point where I wonder: is it really just context-sensitive-grammar matching? Is it a

Answer 1

The way I see it:

• Regular languages:
  • Matched by state machines. Only one variable can be used to represent the current "location" in the grammar to be matched: Recursion cannot be implemented
• Context-free languages:
  • Matched by a stack machine. The current "location" in the grammar is represented by a stack in one or another form. Cannot "remember" anything that occurred before
• Context-sensitive languages:
  • Most programming languages
  • All Most human languages

I do know of regular expression parsers that allow you to match against something the parser has already encountered, achieving something like a context-sensitive grammar.

Still, regular expression parsers, however sophisticated they may be, don't allow for recursive application of rules, which is a definite requirement for context-free grammars.

The term regex, in my opinion, mostly refers to the syntax used to express those regular grammars (the stars and question marks).