Simplify README

Author: khvzak

README.md

@@ -1,104 +1,8 @@
-# Lua 5.3 in Rust - HACK-3870
+# Lua 5.3 port to Rust
 
-# How to get started
+This is a port of [Lua] [5.3] to the Rust programming language with goal to provide backward compatibility with the PUC Lua, including the C API layer.
 
-  * Install rust (needs to be a nightly)
-    * curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
-    * rustup default nightly
-  * `cargo b` to build
-  * `cargo test` to run the tests
-
-# Working on stuff
-
- * Send Alex (aorlenko/khvzak) your github username to be added to the repo to push branches (so you don't have to work from a fork).
- * Please don't push to master unless the tests pass!
- * Not everything needs porting. E.g. rust supplies printf already, so you don't need to port this
- * Note `cstr!` from `macros.rs`, lua uses C strings (0 byte terminated) rust doesn't, this macro helps with that.
-   * You can replace byte terminated strings with this macro in vscode using the following find and replace regex: `b"(.*)\\0" as \*const u8 as \*const c_char` and `cstr!("$1")`
-
-# Project tracking
-
-  https://docs.google.com/document/d/1NmWf19Xf47-Y99b6yKMzoyr2vY6hWXaxNHi1I4nL_vA/
-
-
-# Examples
-
-## Tests
-
-https://www.lua.org/tests/
-
-Start at `tests/tests.rs`
-
-This sets up a lua environment and then runs the lua 5.3 tests.
-
-# C to rust transpiler
-
-https://github.com/immunant/c2rust
-
-See `onelua.rs` - lua C code transpiled, could be helpful, but kinda hell code
-
-Lots of C preprocessor + macros
-
-Does not include the lua standard libraries at the moment
-
-## How to port files
-
-See `build/` and specifically `build/build.rs` - this includes the mapping of all C files built and what rust code to link them with.
-
-Once things are ported, the `.c` files can be removed (but the `.h` files cannot). Any `.c` code in `build/` is still to be moved and should be deleted once moved.
-
-## Using rust code from C
-
-Search for anything with `[no_mangle]`.
-
-E.g. from lstate.rs
-
-    /*
-    ** set GCdebt to a new value keeping the value (totalbytes + GCdebt)
-    ** invariant (and avoiding underflows in 'totalbytes')
-    */
-    #[no_mangle]
-    pub unsafe extern "C" fn luaE_setdebt(g: *mut global_State, debt: l_mem) {
-        let tb = gettotalbytes(g);
-        debug_assert!(tb > 0);
-        (*g).totalbytes = tb as isize - debt;
-        (*g).GCdebt = debt;
-    }
-
-## Using C code from rust
-
-Lua C API https://www.lua.org/pil/24.html
-
-See in lgc.rs
-
-    extern "C" {
-        pub fn luaC_upvalbarrier_(L: *mut lua_State, uv: *mut UpVal);
-        pub fn luaC_barrierback_(L: *mut lua_State, t: *mut Table);
-        pub fn luaC_fix(L: *mut lua_State, o: *mut GCObject);
-        pub fn luaC_newobj(L: *mut lua_State, tt: c_int, sz: size_t) -> *mut GCObject;
-        pub fn luaC_step(L: *mut lua_State);
-        pub fn luaC_freeallobjects(L: *mut lua_State);
-        pub fn luaC_fullgc(L: *mut lua_State, isemergency: c_int);
-        pub fn luaC_barrier_(L: *mut lua_State, o: *mut GCObject, v: *mut GCObject);
-    }
-
-## Refactoring
-
-Take some of the ready made `.rs` rust code and make more idiomatic.
-
-  * Remove raw pointers
-  * Use methods
-  * Stop calculating hashes and use rust native
-  * Use primitives like vectors
-  * Remove libc
-
-## Exceptions
-
-Lua uses exceptions a lot (both in lua + in the C api). C by it's nature doesn't have exceptions, so the C api uses `setjmp` and `longjmp`.
-
-Replace with Rust native implementation of exceptions.
-
-## Wrapping
-
-Lua uses integer number overflow and wraparound explcitily. In rust this will cause an exception.
+Currently the project is in progress and cannot be used.
 
+[Lua]: https://www.lua.org
+[5.3]: https://www.lua.org/manual/5.3/manual.html