https://github.com/kuitang/Turing-Machinery

A bytecode interpreter for a bidirectional, infinite-length-tape Turing machine.
https://github.com/kuitang/Turing-Machinery

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A bytecode interpreter for a bidirectional, infinite-length-tape Turing machine.

• Host: GitHub
• URL: https://github.com/kuitang/Turing-Machinery
• Owner: kuitang
• Created: 2011-06-16T03:30:58.000Z (about 13 years ago)
• Default Branch: master
• Last Pushed: 2011-06-16T03:36:43.000Z (about 13 years ago)
• Last Synced: 2024-01-29T06:35:21.986Z (5 months ago)
• Language: C
• Homepage:
• Size: 93.8 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.markdown

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• AwesomeInterpreter - Turing-Machinery

README

        
A bytecode interpreter for a bidirectional, infinite-length-tape Turing machine.

My definition of the Turing machine is based on Martin Davis, _Computability and Unsolvability_, Dover, 1982 (originally McGraw Hill, 1958), page 5.

Define a Turing machine in an input file as follows:

-   Line 1: two integers, separated by space: initial length of tape, index of tape's start position (0-based)

-   Line 2: a string: initial contents of tape.

-   Line 3: two characters, separated by space: initial state of the machine, "blank" symbol (used to fill new squares on the tape)

-   Lines 3 to n: a four character quadruple _pabq_. When the machine is in state _p_ and the tape is over the square with character _a_, then the machine will write character _b_ and switch to state _q_.

    -   The special characters L and R move the tape reader left or right by one square and do not write anything.

Note that all states and tape symbols are limited to one character. However, they live in separate "namespaces:" you can have a state 2 and a tape symbol 2 with no relation to each other.

Example Turing Machine that does not halt (from page 5 of Davis):

    4 1

    2052

    1 0

    10R1

    12R1

    15R1

    1352

    25L3

    3053

    3253

    3353

If we save this as tm.txt, we can run

    ./tm tm.txt

    Begin: 2052

    2002

    2000

    20000

    200000

    2000000

And so forth.