nim-wiki/GSoC-2014-Ideas.md

# Introduction
Below is a list of project ideas for [GSoC](https://www.google-melange.com/gsoc/homepage/google/gsoc2014) 2014. All these projects require familiarity with the Nimrod programming language, or at minimum, experience with similar programming languages such as C, C#, Java, Python, etc. It is absolutely essential that you become familiar with Nimrod ahead of time.

[Nimrod](http://nimrod-lang.org) is a statically typed programming language which compiles primarily to C. Areas of the project you may wish to work on include the [Nimrod compiler](#wiki-nimrod-compiler) which is itself written in Nimrod, Nimrod's [standard library](#wiki-standard-library) and/or the [tools and infrastructure](#wiki-tools--infrastructure) of Nimrod which includes the Nimrod build farm (Nimbuild) and the Nimrod package manager (babel).

We encourage you to join the #nimrod IRC channel on Freenode to discuss these projects with the community and our mentors. The Nimrod [Forum](http://forum.nimrod-lang.org) is also available. Because communication is a big part of open source development you are expected to get in touch with us before making your application, failure to do so will put your application at a great disadvantage.

The following list of projects are just some ideas that the community and the developers have come up with. You will be contributing to a programming language so there is a lot of flexibility when it comes to the projects that you can work on, this list is certainly not comprehensive so we are happy to hear any suggestions that you may have.

# Projects

## Nimrod Compiler
#### Add support for full coroutines

**Desirable skills:** Knowledge of coroutines, C and Assembly language.

**Description:**

Implement proper coroutines that provide light-weight collaborative multi-tasking. The coroutines must be cooperative - this means a coroutine is suspended only when it explicitly yields. The coroutines must never be migrated across threads - this means that of all the coroutines started from a thread, exactly one is running at any point in time while the others are suspended. Other semantic details are to be nailed down as part of the project.

Nimrod already supports "closure iterators" which are comparable to Python's generators. However closure iterators are much less powerful than proper coroutines because they don't allow capturing the full call stack. This means, for instance, that closure iterators cannot be recursive.

Here is a sketch of a possible implementation, but there are lots of other possibilities to implement full coroutines for Nimrod:

  * Implement the necessary stack switching via inline assembler.
  * The GC needs to support conservative marking of multiple stacks.
  * In particular the write barrier in the GC which does the 'isOnStack' check needs to be changed.
  * Using a bloom filter for quick testing whether an address belongs to some stack is likely to pay off.
  * Creating a coroutine needs to register a new stack to the GC.
  * Deleting a coroutine needs to unregister the stack to the GC.
  * Builtin 'yld' must save the current stack pointer so that the GC knows which part of the stack is really in use.

**Expected Result:** A working coroutine implementation in Nimrod that plays well with the GC.

**Difficulty:** Hard

**Mentor:** Araq ([@Araq](http://github.com/Araq))

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#### Add a code generator for OpenCL
  **Desirable skills:** Good OpenCL knowledge, knowledge of the compiler internals, basics of type theory.


**Description:**

Nimrod currently supports C, C++, Objective C and JavaScript code generation. However to run efficiently on GPUs an OpenCL backend is required. The easy way to do this is to copy OpenCL's low level mode of operation with its different ``private``, ``local``, ``global`` storage and simply provide a nimrodic syntax for OpenCL. So apart from syntactic sugar users get all of Nimrod's meta programming advantages plus good integration into Nimrod's infrastructure.  

The vision is a ``gpu`` pragma that means a proc and all of its dependencies are translated into OpenCL instead of C but can be invoked from ordinary Nimrod code that is translated to C. The ``gpu`` code generator is allowed to only translate a subset of Nimrod, in particular things like function pointers that are not supported by OpenCL do not have to be supported. The compiler should produce a clean error message for unsupported features.

**Expected Result:** The GPU code generator works on a selected set of examples/test cases.

**Tasks:**
  * Add support for new pointer types in the compiler like ``global``, ``private``.
  * Add support for workg groupss.
  * Add support for the ``gpu`` pragma that translates to the OpenCL, version 2: https://www.khronos.org/registry/cl/sdk/2.0/docs/man/xhtml/

**Bonus points:** Support version 1.2 of the OpenCL specification: https://www.khronos.org/registry/cl/sdk/1.2/docs/man/xhtml/. This should be significantly harder as version 1.2 doesn't support a shared address space with the host environment.


**Difficulty:** Hard

**Mentor:** Araq ([@Araq](http://github.com/Araq))

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#### Make Nimrod a viable research platform for Garbage Collection algorithms
  **Desirable skills:** Familiarity with the various GC approaches and algorithms, knowledge of the compiler codegen modules.

**Description:**

Most of the popular garbage collected languages of today require a separately distributed run-time environment, providing only a predetermined set of garbage collection algorithms. This leaves little room for experimentation with various approaches and condemns GC researchers to develop and test their algorithms on specialized platforms such as the [Jikes RVM](http://jikesrvm.org/) that have limited practical significance. 

In contrast, in Nimrod, the garbage collection algorithm is chosen at compile-time and embedded in the resulting stand-alone native executable. This enables the users to pick a GC algorithm that's most suitable to their project and allows for a proliferation of GC algorithms, developed by independent groups and individuals, without requiring any modifications to be made to the standard Nimrod distribution.

The Nimrod code generator and type system can provide various GC roots marking strategies, various kinds of write/read barriers and all necessary static type information (e.g. static cycle analysis) and a GC implementation will consist only of a single Nimrod module (supplied as a command-line parameter) that
provides configuration for the code generator and implements the logic of the garbage collection algorithm. This module will be compiled as C code with the rest of the program and it could be easily debugged using standard C/C++ debugging and profiling tools.

**Tasks:**
  * Add support for precise stack marking
  * Add support for read barriers and polish the support for Levanoni/Petrank style of write barriers
  * Implement the infrastructure for picking a user-supplied GC module

**Bonus points:** Implement simple forms of variety of GC algorithms as a proof-of-concept

**Difficulty:** Medium to Hard

**Mentor:** zahary ([@zah](http://github.com/zah))


___
#### Fix/Expand Nimrod's "Compiler as a Service" and idetools features
**Desirable skills:** Command line argument parsing, good knowledge of compiler internals and theory.

**Description:**

Nimrod's Compiler as a Service feature allows IDEs to query the compiler for things like code suggestions, definition lookups and more. The current implementation works but has some issues.

**Tasks:**
  * Review and resolve related issues.
  * Provide commands to execute macros. Allow IDEs to quickly get the code macros generate with different inputs.
  * Provide a mechanism to track a dirty file without saving it to disk.
  * Provide better diagnostic messages for invalid commands.
  * Add commands to retrieve information about project layout and compilation settings.

**Related issues**: [#804](https://github.com/Araq/Nimrod/issues/804), [#274](https://github.com/Araq/Nimrod/issues/274), [#325](https://github.com/Araq/Nimrod/issues/325), [#452](https://github.com/Araq/Nimrod/issues/452), [#484](https://github.com/Araq/Nimrod/issues/484), [#474](https://github.com/Araq/Nimrod/issues/474), [#477](https://github.com/Araq/Nimrod/issues/477), [#450](https://github.com/Araq/Nimrod/issues/450), [#449](https://github.com/Araq/Nimrod/issues/449), [#415](https://github.com/Araq/Nimrod/issues/415), [#471](https://github.com/Araq/Nimrod/issues/471), [#344](https://github.com/Araq/Nimrod/issues/344)

**Bonus points:** Implement "Compiler as a Service" support to major IDEs/text editors such as Light Table, Sublime Text, or Visual Studio.

**Difficulty:** Medium to Hard

**Mentor:** zahary ([@zah](http://github.com/zah))

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#### Allow bootstrap-time integration of the Nimrod executable with the standard library
**Desirable skills:** Knowledge of file system api's, knowledge of compiler internals and theory.

**Description**:

Allow the nimrod bootstrap process to integrate the nimrod standard library source code and other associated resources into the nimrod binary, to be used by the nimrod binary when compiling source code. The included library modules should be overridable, either by a switch passed to the nimrod executable, or by placing an actual library file in a pre-determined path.

**Difficulty:** Medium

**Mentor:** zahary ([@zah](http://github.com/zah))


## Standard Library

#### Implement a YAML parser library
**Desirable skills:** Ability to write efficient parsers.

**Description**:

The Nimrod standard library currently lacks a YAML parsing module. YAML is a popular "human-readable data serialization format", its popularity is especially evident in the Ruby community. As such it would be a great addition to Nimrod's standard library. This task requires you to read the [YAML specification](http://yaml.org/spec/) and to create a module which will be able to parse YAML data into an AST. Subsequently the parser can be used to create a high-level API to access the data similar to the current design of the [json](http://nimrod-lang.org/json.html) module which provides a low-level parser and a higher-level interface which builds on top of the parser.

**Tasks**:
* Write an efficient parser which will turn YAML data into an AST.
* Design and implement an API on top of the AST to query the data contained in the AST easily.

**Expected Result**: A working YAML module with the ability to read all YAML compliant data.

**Bonus points**: Thorough testing of the YAML module to ensure that the parser works as expected.

**Difficulty:** Medium

**Mentor:** Araq ([@Araq](http://github.com/Araq)), dom96 ([@dom96](http://github.com/dom96))

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#### Enhance the filesystem monitoring module "fsmonitor.nim"
**Desirable skills:** Knowledge of the Microsoft Windows api.

**Description**:
Nimrod's standard library currently has a fsmonitor module which allows the programmer to monitor the filesystem for directory and file changes. This module currently only supports Linux.

**Tasks**:

  * Allow the fsmonitor module to work on Microsoft Windows by using native APIs to gather information about changes in monitored files and directories.
  * Revise the fsmonitor module API to decouple Unix/Linux file handle paradigms (such as using the poll method in the sockets module) from the API, allowing easier implementations of multiple native backends.
  * Integrate the fsmonitor module's polling mechanism into the new asynchronous IO modules.

**Difficulty:** Easy

**Mentor:** dom96 ([@dom96](http://github.com/dom96))

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#### Add a cross-platform stat()-like procedure to the operating system module "os.nim"
**Desirable skills:** Knowledge of file system api's for Linux, MacOSX, or Microsoft Windows.

**Description:**
  * Implement a procedure which uses native stat-like calls on Linux, Mac, Windows, and other operating systems to gather detailed information about specific file system objects. Allow the bypassing of symlinks 
and hardlinks, where possible.

**Difficulty:** Easy

**Mentor:** dom96 ([@dom96](http://github.com/dom96))

___
#### Enhance and expand standard library documentation
**Desirable skills:** Basic writing and documentation skills, web design and infrastructure setup.

**Description**:
  * Ensure that documentation exists for all public methods and modules.
  * Create and design new CSS and HTML layouts for the documentation, to better fit with the main website.
  * Add search capabilities to the online documentation.
  * Add code examples to all modules and to a procedures (where appropriate).

**Difficulty:** Medium

**Mentor:** zahary ([@zah](http://github.com/zah))

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#### Add documentation to the Nimrod compiler internals
**Desirable skills:** Basic writing and documentation skills.

**Description:**
  * Add comments to the compiler internals, documenting the various mechanisms and mechanics the compiler uses to analyze and transform nimrod code to the code of the specified backend.

**Difficulty:** Medium

**Mentor:** Araq ([@Araq](http://github.com/Araq)), zahary ([@zah](http://github.com/zah))

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#### Improve times module
**Desirable skills:** Knowledge of date time representations, native time api's.

**Description**:
  * Fix limitations to do with time intervals, specifically subtracting a TTimeInterval from a TTimeInfo.
  * Provide a ``$`` for TTimeInterval. Goal is to be able to get timing info like "5 minutes ago".

**Difficulty:** Easy

**Mentor:** dom96 ([@dom96](http://github.com/dom96))

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#### Add an implementation of the ISAAC psuedorandom number generator
**Desirable skills:** Pseudo-Random number generation theory, C programming.

**Description:**
  * Create a pure-nimrod implementation of the [[ISAAC Random Number Generator|http://burtleburtle.net/bob/rand/isaacafa.html]] .

**Difficulty:** Medium

**Mentor:** Araq ([@Araq](http://github.com/Araq))

___
#### Wrap and test the Qt framework
**Desirable skills:** Knowledge of C++. Experience with the Qt framework is desirable.

**Description**:
* Wrap the [Qt framework](http://qt-project.org/) with the help of the c2nim tool, or otherwise.
* Write tests which use the wrapper.

**Bonus points:** Write high-level bindings which provide an idiomatic Nimrod API on top of the wrapper.

**Difficulty:** Medium

**Mentor:** Araq ([@Araq](http://github.com/Araq)), zahary ([@zah](http://github.com/zah))
___
#### Wrap and test GTK3
**Desirable skills:** Knowledge of C. Experience with the GTK+ is desirable.

**Description**:
* Wrap GTK3 with the help of the c2nim tool, or otherwise.
* Write tests which use the wrapper.

**Bonus Points:** Write high-level bindings which provide an idiomatic Nimrod API on top of the wrapper.

**Difficulty:** Medium

**Mentor:** dom96 ([@dom96](http://github.com/dom96)), Araq ([@Araq](http://github.com/Araq))

## Tools & Infrastructure
#### Nimbuild
**Desirable skills**: JSON parsing, modular program construction, inter-process communication.

**Description**:
  * Reduce the number of assumptions the Nimrod builder makes about its host system, in order to reduce configuration restrictions. Assumptions include location and usage of external tools, such as git.
  * Implement benchmark tests in the builder and generate graphs showing the time taken to perform those benchmarks on the Nimbuild site. This can include bootstrap times, and test times too.
  * Generate images showing the status of the build to be shown in Nimrod's Github repo and/or Nimrod's website.
  * Improve the download tables on Nimbuild's homepage and generate embeddable download tables for the Nimrod website.

**Difficulty:** Medium

**Mentor:** dom96 ([@dom96](http://github.com/dom96))

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#### Babel
**Desirable skills**: Knowledge of Git and other version control systems.

**Description**:

Babel is the Nimrod package manager. It is currently very basic and some important features are still missing. Babel packages are stored in user-controlled repositories with support for Git and Mercurial currently present.

**Possible tasks:**
  * Add support for other VCS' alongside Git and Mercurial.
  * Create a website which tracks packages similar to hackage, npm, the [DUB registry](http://code.dlang.org/) etc.
  * Add support for the removal of packages.
  * Automate the package submission process.
  * Expand the babel tester to test more dependency scenarios.

**Difficulty:** Medium

**Mentor:** dom96 ([@dom96](http://github.com/dom96))
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#### Implement re2nim, a lexer generator for nimrod

**Description:**
  * Model it after re2c or the Ragel state machine generator
  * Alternatively model it after Flex.

**Desirable skills**: Knowledge of lexer generators. How to translate regexes into DFAs and how to optimize the resulting automatons. 



**Difficulty:** Medium to Hard

**Mentor:** zahary ([@zah](http://github.com/zah))
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#### Implement a Nimrod backend for the Ragel state machine generator

**Description:**
  * Ragel is a widely used state machine generator which supports C, C++ etc. But not Nimrod. So let's change that.
  * http://www.complang.org/ragel/

**Desirable skills**: Knowledge of Ragel's internals.

**Difficulty:** Medium

**Mentor:** zahary ([@zah](http://github.com/zah))

# Template

The following is a rough template that each proposal shall use.

#### Short description

**Desirable skills:** list of desirable skills

**Description:**

Description of the tasks involved.

**Difficulty:** Easy/Medium/Hard

**Mentor:** Potential mentor(s)

___