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Revise docs for 0.19.0.

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Stephen Chung
2020-09-30 23:02:01 +08:00
parent a04ed02b54
commit cbc3d8764a
30 changed files with 291 additions and 125 deletions
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doc/src/about/non-design.md
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@@ -14,7 +14,7 @@ It doesn't attempt to be a new language. For example:
There is, however, a built-in [object map] type which is adequate for most uses.
It is possible to simulate [object-oriented programming (OOP)][OOP] by storing [function pointers]
in [object map] properties, turning them into _methods_.
or [closures] in [object map] properties, turning them into _methods_.
* No first-class functions - Code your functions in Rust instead, and register them with Rhai.
@@ -22,22 +22,32 @@ It doesn't attempt to be a new language. For example:
* 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]({{rootUrl}}/engine/call-fn.md).
* No first-class closures - do your closure magic in Rust instead: [turn a Rhai scripted function into a Rust closure]({{rootUrl}}/engine/call-fn.md).
But you can [curry][currying] a [function pointer] with arguments to simulate it somewhat.
There is, however, support for simulated [closures] via [currying] a [function pointer] with
captured shared variables.
* 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 applications.
* 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 applications.
* No formal language grammar - Rhai uses a hand-coded lexer, a hand-coded top-down recursive-descent parser
for statements and a Pratt parser for expressions.
This lack of formalism allows the parser itself to be exposed as a service in order to support
[disabling keywords/operators][disable keywords and operators], adding [custom operators],
and defining [custom syntax].
Do Not Write The Next 4D VR Game in Rhai
---------------------------------------
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.
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 VM, JIT etc.
Avoid the temptation to write full-fledge application logic entirely in Rhai - that use case is best fulfilled by
more complete languages such as JavaScript or Lua.
Avoid the temptation to write full-fledge application logic entirely in Rhai -
that use case is best fulfilled by more complete languages such as JavaScript or Lua.
Thin Dynamic Wrapper Layer Over Rust Code
@@ -47,7 +57,8 @@ In actual practice, it is usually best to expose a Rust API into Rhai for script
All the core functionalities should be written in Rust, with Rhai being the dynamic _control_ layer.
This is similar to some dynamic languages where most of the core functionalities reside in a C/C++ standard library.
This is similar to some dynamic languages where most of the core functionalities reside in a C/C++
standard library.
Another similar scenario is a web front-end driving back-end services written in a systems language.
In this case, JavaScript takes the role of Rhai while the back-end language, well... it can actually also be Rust.