https://github.com/jez/tsim
A Turing machine simulator in SML
https://github.com/jez/tsim
plt programming-languages sml
Last synced: 8 months ago
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A Turing machine simulator in SML
- Host: GitHub
- URL: https://github.com/jez/tsim
- Owner: jez
- Created: 2016-05-05T21:53:22.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2016-05-05T21:55:29.000Z (over 9 years ago)
- Last Synced: 2025-01-08T18:17:40.293Z (9 months ago)
- Topics: plt, programming-languages, sml
- Language: Standard ML
- Size: 10.7 KB
- Stars: 3
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Turing Machine Simulator
This project implements a Turing machine simulator, and includes a number of
Turing machines to demonstrate how it works.
## Turing Machine Conventions
We choose to represent a Turing machine using the `TURING` signature. This is the
best place to start to gain an understanding of the complete system.
For a quick summary, our `TURING` signature sets up the following conventions:
- a tape alphabet that includes a blank symbol
- a two-way infinite tape, represented as a two-way unbounded array
- a state transition function that allows (but does not require) writing and
moving in the same operation
- a single initial and a single final state
Again, you are encouraged to read the `TURING` signature for more details.
## Building and Running
This code complies cleanly under both SML/NJ and MLton. If possible, we strongly
recommend compiling it using MLton, as it is *orders of magnitude* faster.
### MLton
Once you've installed MLton, building is just one simple command.
You can get usage information by running the command with no arguments.
```console
$ make mlton
$ ./tsim
usage: ./tsim (add|mult|exp)
$ ./tsim add 1 1
[Q0] 11 11
^
[Q1] 11 11
^
[Q1] 11 11
^
[Q1] 11 11
^
[Q2] 11111
^
[Q2] 11111
^
[Q2] 11111
^
[Q3] 11111
^
[Q4] 1111
^
[Q5] 111
^
[Q5] 111
^
[Q5] 111
^
[Q5] 111
^
[Q6] 111
^
Answer: 2
```
### SML/NJ
The build system isn't quite as polished, but it still works well enough.
```console
$ make smlnj
$ sml -m sources.cm app/call-main.sml
... stuff ...
usage: ./tsim (add|mult|exp)
$ sml -m sources.cm app/call-main.sml add 1 1
... stuff ...
[Q0] 11 11
^
[Q1] 11 11
^
[Q1] 11 11
^
[Q1] 11 11
^
[Q2] 11111
^
[Q2] 11111
^
[Q2] 11111
^
[Q3] 11111
^
[Q4] 1111
^
[Q5] 111
^
[Q5] 111
^
[Q5] 111
^
[Q5] 111
^
[Q6] 111
^
Answer: 2
```
## Supported Turing Machines
We implement three Turing machines: addition, multiplication, and
exponentiation. The attributions for these machines can be found in
[Credits](#credits). Each has been implemented ascribing to the `TURING`
signature, and resides in `lib/turing/`.
## Credits
- [Addition Machine][adder]. 15453-s16 FLAC, "Lecture: Turing Machines"
- [Multiplication Machine][multiplier]. Turing machine for multiplication.
YouTube.
- [Exponentiation Machine][exponentiator]. A Turing Machine for Exponential
Function.
[adder]: http://www.cs.cmu.edu/~flac/PDFs/20-turing.pdf
[multiplier]: https://www.youtube.com/watch?v=fUXYL_hywMo
[exponentiator]: http://philpapers.org/archive/LEMATM
## License
[](https://jez.io/MIT-LICENSE.txt)
Copyright Jacob Zimmerman. See badge link above for license information.