User:Epyon/2010/TpServerCppLuaRulesets

From Thousand Parsec Wiki

Abstract

The way that rulesets are implemented in tpserver-cpp is by no means optimal. This project aims at taking care of this in two ways -- first by simplifying the API for ruleset creation and moving all common tasks into the server so they don't need to be repeated for every ruleset -- secondly by providing an even cleaner Lua API over the ruleset creation, as an addition to the possibility of coding them in C++.

Rationale

Doing last years project I've made several changes to the internals of tpserver-cpp, by need I also made changes to the API available to Rulesets. What struck me then was the absurd amount of copy-pasted code between the rulesets -- I'd even risk a bold statement that most of the rulesets share around 70% code. Copy paste has never been a good coding practice, and we'd like to avoid that as much as possible.

Also during that project several ideas came up to me how to simplify that interface. Apart from changes in the API, a toolset (library) of common ruleset code would be much a benefit, and cut down the existing implementations to their core -- to the rules that drive the game.

Once that would be done, we would devise a domain specific language that would define rulesets in a most natural way -- then implement that DSL by using the flexibility of Lua. I can imagine that MiniSec would become 2 or 3 simple files after that -- no more than it would take a person to describe the ruleset in a natural language.

Project immutables

during the whole course of the project, full ruleset compatibility will be maintained -- ergo, once I do a change to the API, I'll take care to update all the projects
once part 1 will be completed, and the Lua interface will be prepared, I'll be porting MiniSec during the implementation of part 2 to Lua, after the Lua API is fully supporting MiniSec, I'll port MTSec, and maybe another ruleset to Lua
at projects end, the ruleset creator will be able to choose in which language to implement his ruleset -- the C++ API will still be threre and fully working
the design of the Lua overlay will be such, that it will take trivial changes to implement any additions to the C++ API

Project goals

Primary goals

rewrite the C++ ruleset API to be much more ruleset design friendly, while maintaining compatibility with all existing rulesets
create a Lua overlay that further simplifies the creation of rulesets up to the verbosity of a natural language definition
port MiniSec to Lua, port all rulesets to take advantage of the new C++ API

Secondary goals

create a support library for ruleset development that includes common code for C++ rulesets
create a component library for Lua that allows immediate ruleset implementation
port MTSec and maybe another ruleset to Lua

Bonus goals

implement the beginnings of EliteSec in Lua ;>

Project schedule

I'll be available probably 4/5 time during the coding period (I need some time for my PhD). Also 10-12 days will probably be spent on a short vacation, although I might still be able to do some work then.

May 10 - May 23 (pre-planning)

Do a research on the content of the existing rulesets, do a research on the needs of ruleset designers, and take a look at the way it is done in tpserver-py too. Plan out the exact details of the schedule.

May 24 - July 12 (phase 1)

upgrade and rewrite the C++ API
port the rulesets to the enhanced API on the go
create a support library and make use of it to remove common code
implement Lua support base in tpserver-cpp
design the Lua API

July 13 - August 9 (phase 2)

port the C++ API directly to Lua, preparing proper metaobjects
refine the Lua API to the designed API, port MiniSec
prepare a component library for Lua
port MTSec, adding things if needed, then if time is left port another ruleset

August 9 - August 16 (buffer)

This week is purposefully left out as buffer time.