Rhai Release Notes ================== Version 0.19.9 ============== This version removes the confusing differences between _packages_ and _modules_ by unifying the terminology and API under the global umbrella of _modules_. Breaking changes ---------------- * `Engine::load_package` is renamed `Engine::register_global_module` and now must explicitly pass a shared [`Module`]. * `Engine::register_module` is renamed `Engine::register_static_module` and now must explicitly pass a shared [`Module`]. * `Package::get` is renamed `Package::as_shared_module`. * `Engine::set_module_resolver` now takes a straight module resolver instead of an `Option`. To disable module resolving, use the new `DummyModuleResolver`. Enhancements ------------ * `Scope` is now `Clone + Hash`. * `Engine::register_static_module` now supports sub-module paths (e.g. `foo::bar::baz`). Version 0.19.8 ============== This version makes it easier to generate documentation for a Rhai code base. Each function defined in an `AST` can optionally attach _doc-comments_ (which, as in Rust, are comments prefixed by either `///` or `/**`). Doc-comments allow third-party tools to automatically generate documentation for functions defined in a Rhai script. A new API, `Engine::gen_fn_metadata_to_json` and `Engine::gen_fn_metadata_with_ast_to_json`, paired with the new `metadata` feature, exports the full list of functions metadata (including those in an `AST`) as a JSON document. There are also a sizable number of bug fixes. Bug fixes --------- * Unary prefix operators `-`, `+` and `!` now bind correctly when applied to an expression. Previously, `-x.len` is parsed as `(-x).len` which is obviously counter-intuitive. * Indexing of namespace-qualified variables now work properly, such as `path::to::var[x]`. * Constants are no longer propagated by the optimizer if shadowed by a non-constant variable. * A constant passed as the `this` parameter to Rhai functions now throws an error if assigned to. * Generic type parameter of `Engine::register_iterator` is `IntoIterator` instead of `Iterator`. * Fixes parsing of block comments ending with `**/` or inner blocks starting with `//*`. Breaking changes ---------------- * `Engine::on_progress` now takes `u64` instead of `&u64`. * The closure for `Engine::on_debug` now takes two additional parameters: `source: Option<&str>` and `pos: Position`. * `AST::iter_functions` now returns `ScriptFnMetadata`. * The parser function passed to `Engine::register_custom_syntax_raw` now takes an additional parameter containing the _look-ahead_ symbol. New features ------------ * `AST::iter_functions` now returns `ScriptFnMetadata` which includes, among others, _doc-comments_ for functions prefixed by `///` or `/**`. * _Doc-comments_ can be enabled/disabled with the new `Engine::set_doc_comments` method. * A new feature `metadata` is added that pulls in `serde_json` and enables `Engine::gen_fn_metadata_to_json` and `Engine::gen_fn_metadata_with_ast_to_json` which exports the full list of functions metadata (including those inside an `AST`) in JSON format. * `Engine::on_debug` provides two additional parameters: `source: Option<&str>` and `pos: Position`, containing the current source (if any) and position of the `debug` statement. * `NativeCallContext` and `EvalContext` both expose `source()` which returns the current source, if any. Enhancements ------------ * A functions lookup cache is added to make function call resolution faster. * Capturing a constant variable in a closure is now supported, with no cloning. * A _look-ahead_ symbol is provided to custom syntax parsers, which can be used to parse variable-length symbol streams. Version 0.19.7 ============== Bug fixes --------- * Fixes compilation errors with certain feature flag combinations. Enhancements ------------ * Property getters/setters and indexers defined in a plugin module are by default `#[rhai_fn(global)]`. * `to_debug` is a new standard function for converting a value into debug format. * Arrays and object maps now print values using `to_debug` (if available). Version 0.19.6 ============== This version adds the `switch` statement. It also allows exposing selected module functions (usually methods) to the global namespace. This is very convenient when encapsulating the API of a custom Rust type into a module while having methods and iterators registered on the custom type work normally. A new `gen_fn_signatures` API enables enumerating the registered functions of an `Engine` for documentation purposes. It also prepares the way for a future reflection API. Bug fixes --------- * Custom syntax that introduces a shadowing variable now works properly. Breaking changes ---------------- * `Module::set_fn`, `Module::set_raw_fn` and `Module::set_fn_XXX_mut` all take an additional parameter of `FnNamespace`. * `Module::set_fn` takes a further parameter with a list of parameter names/types plus the function return type, if any. * `Module::get_sub_module_mut` is removed. * `begin`, `end`, `unless` are now reserved keywords. * `EvalPackage` is removed in favor of `Engine::disable_symbol`. New features ------------ * New `switch` statement. * New `do ... while` and `do ... until` statements. * New `Engine::gen_fn_signatures`, `Module::gen_fn_signatures` and `PackagesCollection::gen_fn_signatures` to generate a list of signatures for functions registered. * New `Engine::register_static_module` to register a module as a sub-module in the global namespace. * New `set_exported_global_fn!` macro to register a plugin function and expose it to the global namespace. * `Module::set_fn_XXX_mut` can expose a module function to the global namespace. This is convenient when registering an API for a custom type. * `Module::set_getter_fn`, `Module::set_setter_fn`, `Module::set_indexer_get_fn`, `Module::set_indexer_set_fn` all expose the function to the global namespace by default. This is convenient when registering an API for a custom type. * New `Module::update_fn_metadata` to update a module function's parameter names and types. * New `#[rhai_fn(global)]` and `#[rhai_fn(internal)]` attributes to determine whether a function defined in a plugin module should be exposed to the global namespace. This is convenient when defining an API for a custom type. * New `get_fn_metadata_list` to get the metadata of all script-defined functions in scope. Enhancements ------------ * New constants under `Dynamic` including `UNIT`, `TRUE`, `FALSE`, `ZERO`, `ONE` etc. * Floating-point numbers ending with a decimal point without a trailing `0` are supported. Version 0.19.5 ============== This version fixes a bug that prevents compilation with the `internals` feature. It also speeds up importing modules. Bug fixes --------- * Fixes compilation error when using the `internals` feature. Bug introduced in `0.19.4`. * Importing script files recursively no longer panics. Breaking changes ---------------- * Modules imported at global level can now be accessed in functions. * `ModuleResolver::resolve` now returns `Shared` for better resources sharing when loading modules. * `ParseErrorType::DuplicatedExport` is removed as multiple `export`'s are now allowed. Enhancements ------------ * Modules imported via `import` statements at global level can now be used in functions. There is no longer any need to re-`import` the modules at the beginning of each function block. * Modules imported via `import` statements are encapsulated into the `AST` when loading a module from a script file. * `export` keyword can now be tagged onto `let` and `const` statements as a short-hand, e.g.: `export let x = 42;` * Variables can now be `export`-ed multiple times under different names. * `index_of`, `==` and `!=` are defined for arrays. * `==` and `!=` are defined for object maps. Version 0.19.4 ============== This version basically cleans up the code structure in preparation for a potential `1.0` release in the future. Most scripts should see a material speed increase. This version also adds a low-level API for more flexibility when defining custom syntax. Bug fixes --------- * Fixes `Send + Sync` for `EvalAltResult` under the `sync` feature. Bug introduced with `0.19.3`. Breaking changes ---------------- * Custom syntax can no longer start with a keyword (even a _reserved_ one), even if it has been disabled. That is to avoid breaking scripts later when the keyword is no longer disabled. Changes to Error Handling ------------------------ * `EvalAltResult::ErrorAssignmentToUnknownLHS` is moved to `ParseError::AssignmentToInvalidLHS`. `ParseError::AssignmentToCopy` is removed. * `EvalAltResult::ErrorDataTooLarge` is simplified. * `Engine::on_progress` closure signature now returns `Option` with the termination value passed on to `EvalAltResult::ErrorTerminated`. * `ParseErrorType::BadInput` now wraps a `LexError` instead of a text string. New features ------------ * `f32_float` feature to set `FLOAT` to `f32`. * Low-level API for custom syntax allowing more flexibility in designing the syntax. * `Module::fill_with` to poly-fill a module with another. * Scripts terminated via `Engine::on_progress` can now pass on a value as a termination token. Enhancements ------------ * Essential AST structures like `Expr` and `Stmt` are packed into smaller sizes (16 bytes and 32 bytes on 64-bit), stored inline for more cache friendliness, and de-`Box`ed as much as possible. * `Scope` is optimized for cache friendliness. Version 0.19.3 ============== This version streamlines some of the advanced API's, and adds the `try` ... `catch` statement to catch exceptions. Breaking changes ---------------- * `EvalAltResult::ErrorReadingScriptFile` is removed in favor of the new `EvalAltResult::ErrorSystem`. * `EvalAltResult::ErrorLoopBreak` is renamed to `EvalAltResult::LoopBreak`. * `Engine::register_raw_fn` and `FnPtr::call_dynamic` function signatures have changed. * Callback signatures to `Engine::on_var` and `Engine::register_custom_syntax` have changed. * `EvalAltResult::ErrorRuntime` now wraps a `Dynamic` instead of a string. * Default call stack depth for `debug` builds is reduced to 8 (from 12) because it keeps overflowing the stack in GitHub CI! * Keyword `thread` is reserved. New features ------------ * The plugins system is enhanced to support functions taking a `NativeCallContext` as the first parameter. * `throw` statement can now throw any value instead of just text strings. * New `try` ... `catch` statement to catch exceptions. Enhancements ------------ * Calling `eval` or `Fn` in method-call style, which is an error, is now caught during parsing. * `func!()` call style is valid even under `no_closure` feature. Version 0.19.2 ============== Bug fix on call module functions. Version 0.19.1 ============== This version adds a variable resolver with the ability to short-circuit variable access, plus a whole bunch of array methods. Breaking changes ---------------- * `AST::iter_functions` now returns an iterator instead of taking a closure. * `Module::get_script_function_by_signature` renamed to `Module::get_script_fn` and returns `&>`. * `Module::num_fn`, `Module::num_var` and `Module::num_iter` are removed and merged into `Module::count`. * The `merge_namespaces` parameter to `Module::eval_ast_as_new` is removed and now defaults to `true`. * `GlobalFileModuleResolver` is removed because its performance gain over the `FileModuleResolver` is no longer very significant. * The following `EvalAltResult` variants are removed and merged into `EvalAltResult::ErrorMismatchDataType`: `ErrorCharMismatch`, `ErrorNumericIndexExpr`, `ErrorStringIndexExpr`, `ErrorImportExpr`, `ErrorLogicGuard`, `ErrorBooleanArgMismatch` * `Scope::iter_raw` returns an iterator with an additional field indicating whether the variable is constant or not. * `rhai::ser` and `rhai::de` namespaces are merged into `rhai::serde`. * New reserved symbols: `++`, `--`, `..`, `...`. * Callback signature for custom syntax implementation function is changed to allow for more flexibility. * Default call stack depth for `debug` builds is reduced to 12 (from 16). * Precedence for `~` is raised, while `in` is moved below logic comparison operators. New features ------------ * New `Engine::on_var` to register a _variable resolver_. * `const` statements can now take any expression (or none at all) instead of only constant values. * `OptimizationLevel::Simple` now eagerly evaluates built-in binary operators of primary types (if not overloaded). * `is_def_var()` to detect if variable is defined, and `is_def_fn()` to detect if script function is defined. * `Dynamic::from(&str)` now constructs a `Dynamic` with a copy of the string as value. * `AST::combine` and `AST::combine_filtered` allows combining two `AST`'s without creating a new one. * `map`, `filter`, `reduce`, `reduce_rev`, `some`, `all`, `extract`, `splice`, `chop` and `sort` functions for arrays. * New `Module::set_iterable` and `Module::set_iterator` to define type iterators more easily. `Engine::register_iterator` is changed to use the simpler version. Enhancements ------------ * Many one-liners and few-liners are now marked `#[inline]` or `[inline(always)]`, just in case it helps when LTO is not turned on. Version 0.19.0 ============== The major new feature for this version is _Plugins_ support, powered by procedural macros. Plugins make it extremely easy to develop and register Rust functions with an `Engine`. Bug fixes --------- * `if` statement with an empty `true` block would not evaluate the `false` block. This is now fixed. * Fixes a bug in `Module::set_fn_4_mut`. * Module API's now properly handle `&str` and `String` parameters. * Indexers are available under `no_object`. * Registered operator-assignment functions (e.g. `+=`) now work correctly. Breaking changes ---------------- * `Engine::register_set_result` and `Engine::register_indexer_set_result` now take a function that returns `Result<(), Box>`. * `Engine::register_indexer_XXX` and `Module::set_indexer_XXX` panic when the type is `Array`, `Map` or `String`. * `EvalAltResult` has a new variant `ErrorInModule` which holds errors when loading an external module. * `Module::eval_ast_as_new` now takes an extra boolean parameter, indicating whether to encapsulate the entire module into a separate namespace. * Functions in `FileModuleResolver` loaded modules now can cross-call each other in addition to functions in the global namespace. For the old behavior, use `MergingFileModuleResolver` instead. * New `EvalAltResult::ErrorInModule` variant capturing errors when loading a module from a script file. New features ------------ * Plugins support via procedural macros. * Scripted functions are allowed in packages. * `parse_int` and `parse_float` functions for parsing numbers; `split` function for splitting strings. * `AST::iter_functions` and `Module::iter_script_fn_info` to iterate functions. * Functions iteration functions for `AST` and `Module` now take `FnMut` instead of `Fn`. * New `FileModuleResolver` that encapsulates the entire `AST` of the module script, allowing function cross-calling. The old version is renamed `MergingFileModuleResolver`. * `+` and `-` operators for timestamps to increment/decrement by seconds. Version 0.18.3 ============== Bug fixes --------- * `Engine::compile_expression`, `Engine::eval_expression` etc. no longer parse anonymous functions and closures. * Imported modules now work inside closures. * Closures that capture now work under `no_object`. New features ------------ * Adds `Module::combine_flatten` to combine two modules while flattening to the root level. Version 0.18.2 ============== Bug fixes --------- * Fixes bug that prevents calling functions in closures. * Fixes bug that erroneously consumes the first argument to a namespace-qualified function call. New features ------------ * Adds `Engine::register_get_result`, `Engine::register_set_result`, `Engine::register_indexer_get_result`, `Engine::register_indexer_set_result` API. * Adds `Module::combine` to combine two modules. * `Engine::parse_json` now also accepts a JSON object starting with `#{`. Version 0.18.1 ============== This version adds: * Anonymous functions (in Rust closure syntax). Simplifies creation of single-use ad-hoc functions. * Currying of function pointers. * Closures - auto-currying of anonymous functions to capture shared variables from the external scope. Use the `no_closure` feature to disable sharing values and capturing. * Binding the `this` pointer in a function pointer `call`. * Capturing call scope via `func!(...)` syntax. New features ------------ * `call` can now be called function-call style for function pointers - this is to handle builds with `no_object`. * Reserve language keywords, such as `print`, `eval`, `call`, `this` etc. * `x.call(f, ...)` allows binding `x` to `this` for the function referenced by the function pointer `f`. * Anonymous functions are supported in the syntax of a Rust closure, e.g. `|x, y, z| x + y - z`. * Custom syntax now works even without the `internals` feature. * Currying of function pointers is supported via the new `curry` keyword. * Automatic currying of anonymous functions to capture shared variables from the external scope. * Capturing of the calling scope for function call via the `func!(...)` syntax. * `Module::set_indexer_get_set_fn` is added as a short-hand of both `Module::set_indexer_get_fn` and `Module::set_indexer_set_fn`. * New `unicode-xid-ident` feature to allow [Unicode Standard Annex #31](http://www.unicode.org/reports/tr31/) for identifiers. * `Scope::iter_raw` returns an iterator with a reference to the underlying `Dynamic` value (which may be shared). Breaking changes ---------------- * Language keywords are now _reserved_ (even when disabled) and they can no longer be used as variable names. * Function signature for defining custom syntax is simplified. * `Engine::register_raw_fn_XXX` API shortcuts are removed. * `PackagesCollection::get_fn`, `PackagesCollection::contains_fn`, `Module::get_fn` and `Module::contains_fn` now take an additional `public_only` parameter indicating whether only public functions are accepted. * The iterator returned by `Scope::iter` now contains a clone of the `Dynamic` value (unshared). * `Engine::register_global_module` takes any type that is `Into`. * Error in `Engine::register_custom_syntax` is no longer `Box`-ed. Housekeeping ------------ * Most compilation warnings are eliminated via feature gates. Version 0.17.0 ============== This version adds: * [`serde`](https://crates.io/crates/serde) support for working with `Dynamic` values (particularly _object maps_). * Low-level API to register functions. * Surgically disable keywords and/or operators in the language. * Define custom operators. * Extend the language via custom syntax. Bug fixes --------- * Fixed method calls in the middle of a dot chain. Breaking changes ---------------- * `EvalAltResult::ErrorMismatchOutputType` has an extra argument containing the name of the requested type. * `Engine::call_fn_dynamic` take an extra argument, allowing a `Dynamic` value to be bound to the `this` pointer. * Precedence of the `%` (modulo) operator is lowered to below `<<` ad `>>`. This is to handle the case of `x << 3 % 10`. New features ------------ * New `serde` feature to allow serializing/deserializing to/from `Dynamic` values using [`serde`](https://crates.io/crates/serde). This is particularly useful when converting a Rust `struct` to a `Dynamic` _object map_ and back. * `Engine::disable_symbol` to surgically disable keywords and/or operators. * `Engine::register_custom_operator` to define a custom operator. * `Engine::register_custom_syntax` to define a custom syntax. * New low-level API `Engine::register_raw_fn`. * New low-level API `Module::set_raw_fn` mirroring `Engine::register_raw_fn`. * `AST::clone_functions_only`, `AST::clone_functions_only_filtered` and `AST::clone_statements_only` to clone only part of an `AST`. * The boolean `^` (XOR) operator is added. * `FnPtr` is exposed as the function pointer type. * `rhai::module_resolvers::ModuleResolversCollection` added to try a list of module resolvers. * It is now possible to mutate the first argument of a namespace-qualified function call when the argument is a simple variable (but not a module constant). * Many configuration/setting API's now returns `&mut Self` so that the calls can be chained. * `String` parameters in functions are supported (but inefficiently). Version 0.16.1 ============== Bug fix release to fix errors when compiling with features. Version 0.16.0 ============== The major new feature in this version is OOP - well, poor man's OOP, that is. The `README` is officially transferred to [The Rhai Book](https://schungx.github.io/rhai). An online [Playground](https://alvinhochun.github.io/rhai-demo/) is available. Breaking changes ---------------- * The trait function `ModuleResolver::resolve` no longer takes a `Scope` as argument. * Functions defined in script now differentiates between using method-call style and normal function-call style. The method-call style will bind the object to the `this` parameter instead of consuming the first parameter. * Imported modules are no longer stored in the `Scope`. `Scope::push_module` is removed. Therefore, cannot rely on module imports to persist across invocations using a `Scope`. * `AST::retain_functions` is used for another purpose. The old `AST::retain_functions` is renamed to `AST::clear_statements`. New features ------------ * Support for _function pointers_ via `Fn(name)` and `Fn.call(...)` syntax - a poor man's first-class function. * Support for calling script-defined functions in method-call style with `this` binding to the object. * Special support in object maps for OOP. * Expanded the `AST` API for fine-tuned manipulation of functions. 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 short-hand. 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.