kjuulh/rhai
1
0
Fork 0
Code Issues 1 Pull Requests 1 Packages Projects Releases Wiki Activity

Add writeup on Rhai usage scenarios.

Browse Source
This commit is contained in:
Stephen Chung
2020-05-31 15:55:02 +08:00
parent 840afe74bb
commit 697bb39a7f
2 changed files with 19 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
README.md
View File

@@ -19,8 +19,8 @@ Features
including [getters/setters](#getters-and-setters), [methods](#members-and-methods) and [indexers](#indexers).
* Freely pass Rust variables/constants into a script via an external [`Scope`].
* Easily [call a script-defined function](#calling-rhai-functions-from-rust) from Rust.
* Low compile-time overhead (~0.6 sec debug/~3 sec release for `rhai_runner` sample app).
* Fairly efficient evaluation (1 million iterations in 0.75 sec on my 5 year old laptop).
* Fairly low compile-time overhead.
* Fairly efficient evaluation (1 million iterations in 0.25 sec on a single core, 2.3 GHz Linux VM).
* Relatively little `unsafe` code (yes there are some for performance reasons, and most `unsafe` code is limited to
one single source file, all with names starting with `"unsafe_"`).
* Re-entrant scripting [`Engine`] can be made `Send + Sync` (via the [`sync`] feature).
@@ -47,10 +47,22 @@ It doesn't attempt to be a new language. For example:
* No classes. Well, Rust doesn't either. On the other hand...
* No traits... so it is also not Rust. Do your Rusty stuff in Rust.
* No structures - define your types in Rust instead; Rhai can seamlessly work with _any Rust type_.
* No structures/records - define your types in Rust instead; Rhai can seamlessly work with _any Rust type_.
There is, however, a built-in [object map] type which is adequate for most uses.
* No first-class functions - Code your functions in Rust instead, and register them with Rhai.
* No garbage collection - this should be expected, so...
* No closures - do your closure magic in Rust instead; [turn a Rhai scripted function into a Rust closure](#calling-rhai-functions-from-rust).
* It is best to expose an API in Rhai for scripts to call. All your core functionalities should be in Rust.
* No byte-codes/JIT - Rhai has an AST-walking interpreter which will not win any speed races. The purpose of Rhai is not
to be extremely _fast_, but to make it as easy as possible to integrate with native Rust programs.
Due to this intended usage, Rhai deliberately keeps the language simple and small by omitting advanced language features
such as classes, inheritance, first-class functions, closures, concurrency, byte-codes, JIT etc.
Avoid the temptation to write full-fledge program logic entirely in Rhai - that use case is best fulfilled by
more complete languages such as JS or Lua.
Therefore, in actual practice, it is usually best to expose a Rust API into Rhai for scripts to call.
All your core functionalities should be in Rust.
This is similar to some dynamic languages where most of the core functionalities reside in a C/C++ standard library.
Installation
------------