Rhai Release Notes ================== Version 0.15.2 ============== Breaking changes ---------------- * The trait function `ModuleResolver::resolve` no longer takes a `Scope` as argument. Enhancements ------------ * [The Rhai Book](https://schungx.github.io/rhai) is online. Most content in the original `README` was transferred to the Book. * New feature `internals` to expose internal data structures (e.g. the AST nodes). Version 0.15.1 ============== This is a minor release which enables updating indexers (via registered indexer setters) and supports functions with `&str` parameters (maps transparently to `ImmutableString`). WASM is also a tested target. Bug fix ------- * `let s="abc"; s[1].change_to('X');` now correctly sets the character '`X`' into '`s`' yielding `"aXc"`. Breaking changes ---------------- * Callback closure passed to `Engine::on_progress` now takes `&u64` instead of `u64` to be consistent with other callback signatures. * `Engine::register_indexer` is renamed to `Engine::register_indexer_get`. * `Module::set_indexer_fn` is renamed to `Module::set_indexer_get_fn`. * The tuple `ParseError` now exposes the internal fields and the `ParseError::error_type` and `ParseError::position` methods are removed. The first tuple field is the `ParseErrorType` and the second tuple field is the `Position`. * `Engine::call_fn_dynamic` now takes any type that implements `IntoIterator`. New features ------------ * Indexers are now split into getters and setters (which now support updates). The API is split into `Engine::register_indexer_get` and `Engine::register_indexer_set` with `Engine::register_indexer_get_set` being a shorthand. Similarly, `Module::set_indexer_get_fn` and `Module::set_indexer_set_fn` are added. * `Engine:register_fn` and `Engine:register_result_fn` accepts functions that take parameters of type `&str` (immutable string slice), which maps directly to `ImmutableString`. This is to avoid needing wrappers for functions taking string parameters. * Set maximum limit on data sizes: `Engine::set_max_string_size`, `Engine::set_max_array_size` and `Engine::set_max_map_size`. * Supports trailing commas on array literals, object map literals, function definitions and function calls. * Enhances support for compiling to WASM. Version 0.15.0 ============== This version uses immutable strings (`ImmutableString` type) and built-in operator functions (e.g. `+`, `>`, `+=`) to improve speed, plus some bug fixes. Regression fix -------------- * Do not optimize script with `eval_expression` - it is assumed to be one-off and short. Bug fixes --------- * Indexing with an index or dot expression now works property (it compiled wrongly before). For example, `let s = "hello"; s[s.len-1] = 'x';` now works property instead of causing a runtime error. * `if` expressions are not supposed to be allowed when compiling for expressions only. This is fixed. Breaking changes ---------------- * `Engine::compile_XXX` functions now return `ParseError` instead of `Box`. * The `RegisterDynamicFn` trait is merged into the `RegisterResultFn` trait which now always returns `Result>`. * Default maximum limit on levels of nested function calls is fine-tuned and set to a different value. * Some operator functions are now built in (see _Speed enhancements_ below), so they are available even under `Engine::new_raw`. * Strings are now immutable. The type `rhai::ImmutableString` is used instead of `std::string::String`. This is to avoid excessive cloning of strings. All native-Rust functions taking string parameters should switch to `rhai::ImmutableString` (which is either `Rc` or `Arc` depending on whether the `sync` feature is used). * Native Rust functions registered with the `Engine` also mutates the first argument when called in normal function-call style (previously the first argument will be passed by _value_ if not called in method-call style). Of course, if the first argument is a calculated value (e.g. result of an expression), then mutating it has no effect, but at least it is not cloned. * Some built-in methods (e.g. `len` for string, `floor` for `FLOAT`) now have _property_ versions in addition to methods to simplify coding. New features ------------ * Set limit on maximum level of nesting expressions and statements to avoid panics during parsing. * New `EvalPackage` to disable `eval`. * `Module::set_getter_fn`, `Module::set_setter_fn` and `Module:set_indexer_fn` to register getter/setter/indexer functions. * `Engine::call_fn_dynamic` for more control in calling script functions. Speed enhancements ------------------ * Common operators (e.g. `+`, `>`, `==`) now call into highly efficient built-in implementations for standard types (i.e. `INT`, `FLOAT`, `bool`, `char`, `()` and `ImmutableString`) if not overridden by a registered function. This yields a 5-10% speed benefit depending on script operator usage. Scripts running tight loops will see significant speed-up. * Common assignment operators (e.g. `+=`, `%=`) now call into highly efficient built-in implementations for standard types (i.e. `INT`, `FLOAT`, `bool`, `char`, `()` and `ImmutableString`) if not overridden by a registered function. * Implementations of common operators for standard types are removed from the `ArithmeticPackage` and `LogicPackage` (and therefore the `CorePackage`) because they are now always available, even under `Engine::new_raw`. * Operator-assignment statements (e.g. `+=`) are now handled directly and much faster. * Strings are now _immutable_ and use the `rhai::ImmutableString` type, eliminating large amounts of cloning. * For Native Rust functions taking a first `&mut` parameter, the first argument is passed by reference instead of by value, even if not called in method-call style. This allows many functions declared with `&mut` parameter to avoid excessive cloning. For example, if `a` is a large array, getting its length in this manner: `len(a)` used to result in a full clone of `a` before taking the length and throwing the copy away. Now, `a` is simply passed by reference, avoiding the cloning altogether. * A custom hasher simply passes through `u64` keys without hashing to avoid function call hash keys (which are by themselves `u64`) being hashed twice. Version 0.14.1 ============== The major features for this release is modules, script resource limits, and speed improvements (mainly due to avoiding allocations). New features ------------ * Modules and _module resolvers_ allow loading external scripts under a module namespace. A module can contain constant variables, Rust functions and Rhai functions. * `export` variables and `private` functions. * _Indexers_ for Rust types. * Track script evaluation progress and terminate script run. * Set limit on maximum number of operations allowed per script run. * Set limit on maximum number of modules loaded per script run. * A new API, `Engine::compile_scripts_with_scope`, can compile a list of script segments without needing to first concatenate them together into one large string. * Stepped `range` function with a custom step. Speed improvements ------------------ ### `StaticVec` A script contains many lists - statements in a block, arguments to a function call etc. In a typical script, most of these lists tend to be short - e.g. the vast majority of function calls contain fewer than 4 arguments, while most statement blocks have fewer than 4-5 statements, with one or two being the most common. Before, dynamic `Vec`'s are used to hold these short lists for very brief periods of time, causing allocations churn. In this version, large amounts of allocations are avoided by converting to a `StaticVec` - a list type based on a static array for a small number of items (currently four) - wherever possible plus other tricks. Most real-life scripts should see material speed increases. ### Pre-computed variable lookups Almost all variable lookups, as well as lookups in loaded modules, are now pre-computed. A variable's name is almost never used to search for the variable in the current scope. _Getters_ and _setter_ function names are also pre-computed and cached, so no string allocations are performed during a property get/set call. ### Pre-computed function call hashes Lookup of all function calls, including Rust and Rhai ones, are now through pre-computed hashes. The function name is no longer used to search for a function, making function call dispatches much faster. ### Large Boxes for expressions and statements The expression (`Expr`) and statement (`Stmt`) types are modified so that all of the variants contain only one single `Box` to a large allocated structure containing _all_ the fields. This makes the `Expr` and `Stmt` types very small (only one single pointer) and improves evaluation speed due to cache efficiency. Error handling -------------- Previously, when an error occurs inside a function call, the error position reported is the function call site. This makes it difficult to diagnose the actual location of the error within the function. A new error variant `EvalAltResult::ErrorInFunctionCall` is added in this version. It wraps the internal error returned by the called function, including the error position within the function.