Are regular languages Turing complete?
Virtually all programming languages today are Turing-complete. The concept is named after English mathematician and computer scientist Alan Turing. No physical system can have infinite memory, but if the limitation of finite memory is ignored, most programming languages are otherwise Turing-complete.
What languages are not Turing complete?
There are no mainstream multi-purpose non Turing complete languages today. There are, however, several non Turing complete domain specific languages. ANSI SQL, regular expressions, data languages (HTML, CSS, JSON, etc), and s-expressions are some notable examples.
Why are regular expressions not Turing-complete?
A Turing-complete language is able to simulate a Turing machine, which processes an unrestricted language. A regular language is the least expressive type of formal language, while an unrestricted language is the most expressive type. So, no, regular languages aren’t Turing-complete.
Can Turing machine take regular language?
Turing machines (TM) Finite state automata can be used to recognize only regular languages. To recognize a context-free grammar, we need to use a pushdown automaton.
What Turing-complete means?
Practically, what you need to know is that a Turing-complete language (also called a universal language) is one where you can compute anything that any other computational method can compute. In other words, a language that’s non-universal—or Turing incomplete—has some limits on the set of things that it can compute.
Why is SQL not Turing-complete?
So one of the largest reasons for wanting SQL to not be Turing complete is that you instead prefer to constrain things so that the halting problem can be solved. This is of material value when discussing a query language …
Is Microsoft Excel Turing-complete?
With the addition of custom functions that can call each other and recursively call themselves, Excel’s formula language becomes Turing-complete, effectively meaning that Excel users can compute anything without resorting to another programming language. You can’t define new functions.
Is regular expression a regular language?
Regular Expressions are an algebraic way to describe languages. Regular Expressions describe exactly the regular languages. If E is a regular expression, then L(E) is the regular language it defines. For each regular expression E, we can create a DFA A such that L(E) = L(A).
Can the regular expression be used to represent the syntax of the programming language construct?
No. A regular expression is an instance of an expression of a regular language, which is a formal language that can be used to define patterns to match during searching, parsing, etc.
Is regular expression search and replace Turing-complete?
Repeated find/Replace with regular expressions is a Turing-complete Programming Language As a consequence, you can compute any computable function using the same search and replace javascript regular expression over and over. To prove the turing-completeness, it is sufficient to encode a Turing machine in regular expression search/replace.
Are there any computational languages that are not Turing complete?
Many computational languages exist that are not Turing complete. One such example is the set of regular languages, which are generated by regular expressions and which are recognized by finite automata.
What is the difference between a regular expression and a turning complete?
A regular expression can only define things at are doable on a machine with no memory (finite state machines). A turning complete language needs a least one stack to be lexable (recognized) and needs the equiv of RAM (bi-directional tape.. aka a (universal) Turing machine) to be processed
What are regular expressions?
Regular Expressions are a particular kind of formal grammar used to parse strings and other textual information that are known as “Regular Languages” in formal language theory. They are not a programming language as such.