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36 lines
813 B
Markdown
36 lines
813 B
Markdown
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# Automata Theory: Building a RegExp machine
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## Content:
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State Machines
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Formal Grammars
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Implement a regular expression processor
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## History:
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*Pioneers:*
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1951 - Stephen Kleene invented reg exp (sets).
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Reuglar Langauge : Langauge recognized by a finite automata (state machines).
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Kleene's Therem : Equivalence of regular expressions and finite automata.
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Has a notation named after him:
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Kleene-Closure (AKA: Kleene star) : A* (Stands for repetition)
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1956 - Chomsky defines his hiearchy fo grammers
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Regular grammers are considered a type 3.
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See: https://en.wikipedia.org/wiki/Chomsky_hierarchy
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Thus they are the weakest form of grammars.
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1968 - Ken Thompson used them for pattern matching in strings, and
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lexical analysis (scanners)
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NFA - Thompson construction
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