Learn Thue - 10 Code Examples & CST Typing Practice Test

Thue is an abstract computational model based on string rewriting systems. It allows defining rules to transform strings, serving as a theoretical model for computation and a framework for exploring universal computation.

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Hello World in Thue Simple Increment Simple Decrement Print Numbers 1 to 3 Swap Two Symbols Simple Copy Rule Conditional Output Example Palindrome Check Reverse String Factorial Concept

Learn THUE with Real Code Examples

Updated Nov 26, 2025

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Code Sample Descriptions

Hello World in Thue

::=

::=Hello World!

::=::

A simple Thue program that outputs 'Hello World!'. The rules transform an initial start symbol into the target string.

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Simple Increment

N::=0
N::=N1
N::=N2
N::=N3
N::=N4
N::=N5
N::=N6
N::=N7
N::=N8
N::=N9

Increment a number represented as a string of digits.

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Simple Decrement

D1::=0
D2::=1
D3::=2
D4::=3
D5::=4
D6::=5
D7::=6
D8::=7
D9::=8
D0::=9

Decrement a number represented as a string of digits.

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Print Numbers 1 to 3

S::=1A
A::=2B
B::=3
C::=::
S

Prints numbers 1, 2, 3 sequentially using Thue rules.

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Swap Two Symbols

S::=AB
AB::=BA
BA::=AB

Swaps two symbols A and B in the string.

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Simple Copy Rule

X::=Y
Y::=X

Copies symbol X to Y using Thue rules.

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Conditional Output Example

S::=A?YES:NO
A::=::
S

Outputs 'YES' if symbol A exists, 'NO' otherwise.

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Palindrome Check

S::=ABA
ABA::=PALINDROME
B::=::
S

Checks if a string is a palindrome using Thue transformations.

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Reverse String

S::=ABC
ABC::=CBA
CBA::=ABC

Reverses the string 'ABC' to 'CBA'.

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Factorial Concept

F::=1
F::=F*2
F::=F*3
F::=F*4
F::=RESULT
RESULT::=::
F

A simple conceptual Thue program to illustrate factorial transformation.

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Frequently Asked Questions about Thue

What is Thue?

What are the primary use cases for Thue?

Study of formal languages and rewriting systems. Turing-completeness demonstrations. Exploration of non-deterministic algorithms. Teaching computational theory concepts. Theoretical experiments in automata and computation

What are the strengths of Thue?

Simple yet universal computational model. Demonstrates Turing-completeness in minimal form. Useful for educational purposes in computation theory. Explores non-determinism and computational paths. Highly abstract, applicable to various formal systems

What are the limitations of Thue?

Not practical for real-world programming. Execution can be highly inefficient. Non-deterministic versions are hard to analyze. Limited tooling and software support. Requires strong theoretical background to use effectively

How can I practice Thue typing speed?

CodeSpeedTest offers 10+ real Thue code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Hello World in Thue

::=

::=Hello World!

::=::

A simple Thue program that outputs 'Hello World!'. The rules transform an initial start symbol into the target string.

Let’s Try →

Simple Increment

N::=0
N::=N1
N::=N2
N::=N3
N::=N4
N::=N5
N::=N6
N::=N7
N::=N8
N::=N9

Increment a number represented as a string of digits.

Let’s Try →

Simple Decrement

D1::=0
D2::=1
D3::=2
D4::=3
D5::=4
D6::=5
D7::=6
D8::=7
D9::=8
D0::=9

Decrement a number represented as a string of digits.

Let’s Try →

Print Numbers 1 to 3

S::=1A
A::=2B
B::=3
C::=::
S

Prints numbers 1, 2, 3 sequentially using Thue rules.

Let’s Try →

Swap Two Symbols

S::=AB
AB::=BA
BA::=AB

Swaps two symbols A and B in the string.

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Simple Copy Rule

X::=Y
Y::=X

Copies symbol X to Y using Thue rules.

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Conditional Output Example

S::=A?YES:NO
A::=::
S

Outputs 'YES' if symbol A exists, 'NO' otherwise.

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Palindrome Check

S::=ABA
ABA::=PALINDROME
B::=::
S

Checks if a string is a palindrome using Thue transformations.

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Reverse String

S::=ABC
ABC::=CBA
CBA::=ABC

Reverses the string 'ABC' to 'CBA'.

Let’s Try →

Factorial Concept

F::=1
F::=F*2
F::=F*3
F::=F*4
F::=RESULT
RESULT::=::
F

A simple conceptual Thue program to illustrate factorial transformation.

Let’s Try →

Frequently Asked Questions about Thue

What is Thue?

What are the primary use cases for Thue?

What are the strengths of Thue?

What are the limitations of Thue?

How can I practice Thue typing speed?

CodeSpeedTest offers 10+ real Thue code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.