From 3995761bf105cfc4c41bffb31114dac4deef4967 Mon Sep 17 00:00:00 2001 From: Pavel Date: Thu, 20 May 2021 06:49:25 +0300 Subject: [PATCH] Add README.md --- README.md | 195 +++++++++++++++++++++++++++++++++++++++++++++++++++++ README.rst | 129 ----------------------------------- 2 files changed, 195 insertions(+), 129 deletions(-) create mode 100644 README.md delete mode 100644 README.rst diff --git a/README.md b/README.md new file mode 100644 index 0000000..cb3f061 --- /dev/null +++ b/README.md @@ -0,0 +1,195 @@ +Ravi Programming Language +========================= + +![image](https://travis-ci.org/dibyendumajumdar/ravi.svg?branch=master%0A%20:target:%20https://travis-ci.org/dibyendumajumdar/ravi) + +Ravi is a dialect of [Lua](http://www.lua.org/) with limited optional +static typing and features [MIR](https://github.com/vnmakarov/mir) +powered JIT compilers. The name Ravi comes from the Sanskrit word for +the Sun. Interestingly a precursor to Lua was +[Sol](http://www.lua.org/history.html) which had support for static +types; Sol means the Sun in Portugese. + +Lua is perfect as a small embeddable dynamic language so why a +derivative? Ravi extends Lua with static typing for improved performance +when JIT compilation is enabled. However, the static typing is optional +and therefore Lua programs are also valid Ravi programs. + +There are other attempts to add static typing to Lua - e.g. [Typed +Lua](https://github.com/andremm/typedlua) but these efforts are mostly +about adding static type checks in the language while leaving the VM +unmodified. The Typed Lua effort is very similar to the approach taken +by Typescript in the JavaScript world. The static typing is to aid +programming in the large - the code is eventually translated to standard +Lua and executed in the unmodified Lua VM. + +My motivation is somewhat different - I want to enhance the VM to +support more efficient operations when types are known. Type information +can be exploited by JIT compilation technology to improve performance. +At the same time, I want to keep the language safe and therefore usable +by non-expert programmers. + +Of course there is the fantastic [LuaJIT](http://luajit.org) +implementation. Ravi has a different goal compared to LuaJIT. Ravi +prioritizes ease of maintenance and support, language safety, and +compatibility with Lua 5.3, over maximum performance. For more detailed +comparison please refer to the documentation links below. + +Features +-------- + +- Optional static typing - for details [see the reference + manual](https://the-ravi-programming-language.readthedocs.io/en/latest/ravi-reference.html). +- Type specific bytecodes to improve performance +- Compatibility with Lua 5.3 (see Compatibility section below) +- Generational GC from Lua 5.4 +- `defer` statement for releasing resources +- Compact JIT backend [MIR](https://github.com/vnmakarov/mir). +- A [distribution with + batteries](https://github.com/dibyendumajumdar/Suravi). +- A [Visual Studio Code debugger + extension](https://marketplace.visualstudio.com/items?itemName=ravilang.ravi-debug) + - interpreted mode debugger. + +Documentation +------------- + +- For the Lua extensions in Ravi see the [Reference + Manual](https://the-ravi-programming-language.readthedocs.io/en/latest/ravi-reference.html). +- [MIR JIT Build + instructions](https://the-ravi-programming-language.readthedocs.io/en/latest/ravi-mir-instructions.html). +- Also see [Ravi + Documentation](http://the-ravi-programming-language.readthedocs.org/en/latest/index.html). +- and the slides I presented at the [Lua 2015 + Workshop](http://www.lua.org/wshop15.html). + +Lua Goodies +----------- + +- [An Introduction to + Lua](http://the-ravi-programming-language.readthedocs.io/en/latest/lua-introduction.html) + attempts to provide a quick overview of Lua for folks coming from + other languages. +- [Lua 5.3 Bytecode + Reference](http://the-ravi-programming-language.readthedocs.io/en/latest/lua_bytecode_reference.html) + is my attempt to bring up to date the [Lua 5.1 Bytecode + Reference](http://luaforge.net/docman/83/98/ANoFrillsIntroToLua51VMInstructions.pdf). +- A [patch for Lua + 5.3](https://github.com/dibyendumajumdar/ravi/blob/master/patches/defer_statement_for_Lua_5_3.patch) + implements the 'defer' statement. +- A [patch for Lua + 5.4.[0-2]](https://github.com/dibyendumajumdar/ravi/blob/master/patches/defer_statement_for_Lua_5_4.patch) + implements the 'defer' statement. +- Updated [patch for Lua + 5.4.3](https://github.com/dibyendumajumdar/ravi/blob/master/patches/defer_statement_patch_for_Lua_5_4_3.patch) + implements the 'defer' statement. + +Lua 5.4 Position Statement +-------------------------- + +Lua 5.4 relationship to Ravi is as follows: + +- Generational GC - back-ported to Ravi. +- New random number generator - back-ported to Ravi. +- Multiple user values can be associated with userdata - under + consideration. +- `` variables - not planned. +- `` variables - Ravi has `'defer'` statement which is the + better option in my opinion, hence no plans to support `` + variables. +- Interpreter performance improvements - these are beneficial to Lua + interpreter but not to the JIT backends, hence not much point in + back-porting. +- Table implementation changes - under consideration. +- String to number coercion is now part of string library metamethods + - back-ported to Ravi. +- utf8 library accepts codepoints up to 2\^31 - back-ported to Ravi. +- Removal of compatibility layers for 5.1, and 5.2 - not implemented + as Ravi continues to provide these layers as per Lua 5.3. + +Compatibility with Lua 5.3 +-------------------------- + +Ravi should be able to run all Lua 5.3 programs in interpreted mode, but +following should be noted: + +- Ravi supports optional typing and enhanced types such as arrays (see + the documentation). Programs using these features cannot be run by + standard Lua. However all types in Ravi can be passed to Lua + functions; operations on Ravi arrays within Lua code will be subject + to restrictions as described in the section above on arrays. +- Values crossing from Lua to Ravi will be subjected to typechecks + should these values be assigned to typed variables. +- Upvalues cannot subvert the static typing of local variables (issue + \#26) when types are annotated. +- Certain Lua limits are reduced due to changed byte code structure. + These are described below. +- Ravi uses an extended bytecode which means it is not compatible with + Lua 5.x bytecode. +- Ravi incorporates the new Generational GC from Lua 5.4, hence the GC + interface has changed. + + Limit name Lua value Ravi value + ------------------ -------------- -------------- + MAXUPVAL 255 125 + LUAI\_MAXCCALLS 200 125 + MAXREGS 255 125 + MAXVARS 200 125 + MAXARGLINE 250 120 + +When JIT compilation is enabled there are following additional +constraints: + +- Ravi will only execute JITed code from the main Lua thread; any + secondary threads (coroutines) execute in interpreter mode. +- In JITed code tailcalls are implemented as regular calls so unlike + the interpreter VM which supports infinite tail recursion JIT + compiled code only supports tail recursion to a depth of about 110 + (issue \#17) +- Debug api and hooks are not supported in JIT mode + +History +------- + +- 2015 + : - Implemented JIT compilation using LLVM + - Implemented [libgccjit based alternative + JIT](https://github.com/dibyendumajumdar/ravi/tree/gccjit-ravi534) + (now discontinued) + +- 2016 + : - Implemented debugger for Ravi and Lua 5.3 for [Visual Studio + Code](https://github.com/dibyendumajumdar/ravi/tree/master/vscode-debugger) + +- 2017 + : - Embedded C compiler using dmrC project (C JIT compiler) (now + discontinued) + - Additional type-annotations + +- 2018 + : - Implemented [Eclipse OMR JIT + backend](https://github.com/dibyendumajumdar/ravi/tree/omrjit) + (now discontinued) + - Created [Ravi with + batteries](https://github.com/dibyendumajumdar/Suravi). + +- 2019 + : - New language feature - defer statement + - New JIT backend [MIR](https://github.com/vnmakarov/mir). + +- 2020 + : - [New parser / type checker / + compiler](https://github.com/dibyendumajumdar/ravi-compiler) + - Generational GC back-ported from Lua 5.4 + - Support for [LLVM + backend](https://github.com/dibyendumajumdar/ravi/tree/llvm) + archived + +- 2021 (Plan) + : - Integrated AOT and JIT compilation support + - Ravi 1.0 release + +License +------- + +MIT License diff --git a/README.rst b/README.rst deleted file mode 100644 index 9b42d14..0000000 --- a/README.rst +++ /dev/null @@ -1,129 +0,0 @@ -========================= -Ravi Programming Language -========================= -.. image:: https://travis-ci.org/dibyendumajumdar/ravi.svg?branch=master - :target: https://travis-ci.org/dibyendumajumdar/ravi - -Ravi is a dialect of `Lua `_ with limited optional static typing and -features `MIR `_ powered JIT compilers. -The name Ravi comes from the Sanskrit word for the Sun. -Interestingly a precursor to Lua was `Sol `_ which had support for -static types; Sol means the Sun in Portugese. - -Lua is perfect as a small embeddable dynamic language so why a derivative? Ravi extends Lua with -static typing for improved performance when JIT compilation is enabled. However, the static typing is -optional and therefore Lua programs are also valid Ravi programs. - -There are other attempts to add static typing to Lua - e.g. `Typed Lua `_ but -these efforts are mostly about adding static type checks in the language while leaving the VM unmodified. -The Typed Lua effort is very similar to the approach taken by Typescript in the JavaScript world. -The static typing is to aid programming in the large - the code is eventually translated to standard Lua -and executed in the unmodified Lua VM. - -My motivation is somewhat different - I want to enhance the VM to support more efficient operations when types are -known. Type information can be exploited by JIT compilation technology to improve performance. At the same time, -I want to keep the language safe and therefore usable by non-expert programmers. - -Of course there is the fantastic `LuaJIT `_ implementation. Ravi has a different goal compared to -LuaJIT. Ravi prioritizes ease of maintenance and support, language safety, and compatibility with Lua 5.3, -over maximum performance. For more detailed comparison please refer to the documentation links below. - -Features -======== -* Optional static typing - for details `see the reference manual `_. -* Type specific bytecodes to improve performance -* Compatibility with Lua 5.3 (see Compatibility section below) -* Generational GC from Lua 5.4 -* ``defer`` statement for releasing resources -* Compact JIT backend `MIR `_. -* A `distribution with batteries `_. -* A `Visual Studio Code debugger extension `_ - interpreted mode debugger. - -Documentation -============= -* For the Lua extensions in Ravi see the `Reference Manual `_. -* `MIR JIT Build instructions `_. -* Also see `Ravi Documentation `_. -* and the slides I presented at the `Lua 2015 Workshop `_. - -Lua Goodies -=========== -* `An Introduction to Lua `_ attempts to provide a quick overview of Lua for folks coming from other languages. -* `Lua 5.3 Bytecode Reference `_ is my attempt to bring up to date the `Lua 5.1 Bytecode Reference `_. -* A `patch for Lua 5.3 `_ implements the 'defer' statement. -* A `patch for Lua 5.4.[0-2] `_ implements the 'defer' statement. -* Updated `patch for Lua 5.4.3 `_ implements the 'defer' statement. - -Lua 5.4 Position Statement -========================== -Lua 5.4 relationship to Ravi is as follows: - -* Generational GC - back-ported to Ravi. -* New random number generator - back-ported to Ravi. -* Multiple user values can be associated with userdata - under consideration. -* ```` variables - not planned. -* ```` variables - Ravi has ``'defer'`` statement which is the better option in my opinion, hence no plans to support ```` variables. -* Interpreter performance improvements - these are beneficial to Lua interpreter but not to the JIT backends, hence not much point in back-porting. -* Table implementation changes - under consideration. -* String to number coercion is now part of string library metamethods - back-ported to Ravi. -* utf8 library accepts codepoints up to 2^31 - back-ported to Ravi. -* Removal of compatibility layers for 5.1, and 5.2 - not implemented as Ravi continues to provide these layers as per Lua 5.3. - -Compatibility with Lua 5.3 -========================== -Ravi should be able to run all Lua 5.3 programs in interpreted mode, but following should be noted: - -* Ravi supports optional typing and enhanced types such as arrays (see the documentation). Programs using these features cannot be run by standard Lua. However all types in Ravi can be passed to Lua functions; operations on Ravi arrays within Lua code will be subject to restrictions as described in the section above on arrays. -* Values crossing from Lua to Ravi will be subjected to typechecks should these values be assigned to typed variables. -* Upvalues cannot subvert the static typing of local variables (issue #26) when types are annotated. -* Certain Lua limits are reduced due to changed byte code structure. These are described below. -* Ravi uses an extended bytecode which means it is not compatible with Lua 5.x bytecode. -* Ravi incorporates the new Generational GC from Lua 5.4, hence the GC interface has changed. - -+-----------------+-------------+-------------+ -| Limit name | Lua value | Ravi value | -+=================+=============+=============+ -| MAXUPVAL | 255 | 125 | -+-----------------+-------------+-------------+ -| LUAI_MAXCCALLS | 200 | 125 | -+-----------------+-------------+-------------+ -| MAXREGS | 255 | 125 | -+-----------------+-------------+-------------+ -| MAXVARS | 200 | 125 | -+-----------------+-------------+-------------+ -| MAXARGLINE | 250 | 120 | -+-----------------+-------------+-------------+ - -When JIT compilation is enabled there are following additional constraints: - -* Ravi will only execute JITed code from the main Lua thread; any secondary threads (coroutines) execute in interpreter mode. -* In JITed code tailcalls are implemented as regular calls so unlike the interpreter VM which supports infinite tail recursion JIT compiled code only supports tail recursion to a depth of about 110 (issue #17) -* Debug api and hooks are not supported in JIT mode - -History -======= -* 2015 - - Implemented JIT compilation using LLVM - - Implemented `libgccjit based alternative JIT `_ (now discontinued) -* 2016 - - Implemented debugger for Ravi and Lua 5.3 for `Visual Studio Code `_ -* 2017 - - Embedded C compiler using dmrC project (C JIT compiler) (now discontinued) - - Additional type-annotations -* 2018 - - Implemented `Eclipse OMR JIT backend `_ (now discontinued) - - Created `Ravi with batteries `_. -* 2019 - - New language feature - `defer` statement - - New JIT backend `MIR `_. -* 2020 - - `New parser / type checker / compiler `_ - - Generational GC back-ported from Lua 5.4 - - Support for `LLVM backend `_ archived -* 2021 (Plan) - - Integrated AOT and JIT compilation support - - Ravi 1.0 release - -License -======= -MIT License