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https://github.com/objectionary/demu

A command line tool for DeMutabilization of EO programs
https://github.com/objectionary/demu

code-optimization eolang java oop

Last synced: 2 months ago
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A command line tool for DeMutabilization of EO programs

Host: GitHub
URL: https://github.com/objectionary/demu
Owner: objectionary
License: mit
Created: 2022-12-08T13:14:40.000Z (about 2 years ago)
Default Branch: master
Last Pushed: 2024-11-07T17:23:15.000Z (3 months ago)
Last Synced: 2024-11-07T18:29:09.485Z (3 months ago)
Topics: code-optimization, eolang, java, oop
Language: Java
Homepage:
Size: 58.6 KB
Stars: 4
Watchers: 2
Forks: 1
Open Issues: 10
Metadata Files:
- Readme: README.md
- License: LICENSE.txt

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# DeMu

It's a well known fact that programs with immutable objects much easy to

maintain, test and use, but the main benefit form immutable objects is that they

allow performing

more [aggressive optimizations [1]](https://dl.acm.org/doi/10.1145/583810.583833)

and apply more valuable analysis. **DeMu** is exactly the tool for removing

mutable objects like `memory` and `cage`

from [EO](https://github.com/objectionary/eo) programs. Actually, DeMu is

acronym for **De-Muatabilization**.

## Methodology

There isn't single formal methodology or algorithm for converting mutable

objects into immutable, but we can use some separate methods to achieve this.

### Using SSA form for simple cases

We actually can

apply [SSA [2]](http://www1.cse.wustl.edu/~cytron/cs531/Resources/Papers/valnum.pdf)

form for `eo` programs. This approach can immediately remove some usages of

mutable objects. Let's consider the following example:

```eo

[] > example

  cage 0 > index

  seq > @

    index.write 1

    stdout

      sprintf

        "%s"

        index

    TRUE

```

After applying SSA form we get something like the next:

```eo

[] > example

  seq > @

    stdout

      sprintf

        "%s"

        1

    TRUE

```

And as you can see - we removed usage of `cage` from the result program.

The relation between SSA form and Dataflow Languages (like `EO` and, 

particularly, Functional Programming Languages) is quite well described in

that [article [3]](https://www.cs.princeton.edu/~appel/papers/ssafun.pdf).

### Using recursion for loops

The second method is to convert loops into recursive calls.

## Related articles and links

1. [Immutability specification and its applications](https://dl.acm.org/doi/10.1145/583810.583833)

2. [Global Value Numbers and Redundant Computations](http://www1.cse.wustl.edu/~cytron/cs531/Resources/Papers/valnum.pdf)

3. [SSA is Functional Programming](https://www.cs.princeton.edu/~appel/papers/ssafun.pdf)

## How to Contribute

Fork repository, make changes, send us a pull request. We will review your

changes and apply them to the `master` branch shortly, provided they don't

violate our quality standards. To avoid frustration, before sending us your pull

request please run full Maven build:

```bash

$ mvn clean install -Pqulice

```

You will need Maven 3.3+ and Java 8+.