My Most Important Project Was a Bytecode Interpreter

Re:My Most Important Project Was a Bytecode Interpreter by hvidgaard on Thursday September 22, 2016 @02:17AM (#12554811)

While it is true for Regular Languages (FSM) strict RegExs, it's hardly true for any contemporary implementation of RegExs. They have back references and other constructs that make them more powerful than a Regular Language, and thereby make it impossible to decide equivalence in the general case.

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Re:My Most Important Project Was a Bytecode Interpreter by wyager on Thursday September 22, 2016 @02:55AM (#12554986)

Hence "not to be confused with PCREs", which most pseudo-regex implementations are based off of.

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Re:My Most Important Project Was a Bytecode Interpreter by Hydraulix989 on Thursday September 22, 2016 @03:12AM (#12555052)

I'll ask the "dumb question" then: What is a PCRE? How is it different than a "true" regex?

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Re:My Most Important Project Was a Bytecode Interpreter by robewald on Thursday September 22, 2016 @03:26AM (#12555107)

PCREs are Perl Compatible Regular Expressions, they have backreferences and other constructs. Almost all languages that have Regular Expressions have similar constructs. "Computer Science" Regular Expressions are more limited and implement a "regular language" as defined in https://en.wikipedia.org/wiki/Chomsky_hierarchy. This gives some guarantees, which go out the window with PCREs.

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Re:My Most Important Project Was a Bytecode Interpreter by hvidgaard on Thursday September 22, 2016 @10:00AM (#12556840)

Did you edit the comment? I cannot recall reading that at all, but I may have been in a hurry.

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Re:My Most Important Project Was a Bytecode Interpreter by wyager on Thursday September 22, 2016 @01:34PM (#12558563)

Nope, didn't change it!

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