rhai/src/settings.rs

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//! Configuration settings for `Engine`.
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use crate::engine::Engine;
use crate::optimize::OptimizationLevel;
use crate::packages::PackageLibrary;
use crate::token::{is_valid_identifier, Token};
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#[cfg(not(feature = "no_module"))]
use crate::module::ModuleResolver;
use crate::stdlib::{format, string::String};
#[cfg(not(feature = "no_module"))]
use crate::stdlib::boxed::Box;
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impl Engine {
/// Load a new package into the `Engine`.
///
/// When searching for functions, packages loaded later are preferred.
/// In other words, loaded packages are searched in reverse order.
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pub fn load_package(&mut self, package: PackageLibrary) -> &mut Self {
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// Push the package to the top - packages are searched in reverse order
self.packages.push(package);
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self
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}
/// Control whether and how the `Engine` will optimize an AST after compilation.
///
/// Not available under the `no_optimize` feature.
#[cfg(not(feature = "no_optimize"))]
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pub fn set_optimization_level(&mut self, optimization_level: OptimizationLevel) -> &mut Self {
self.optimization_level = optimization_level;
self
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}
/// The current optimization level.
/// It controls whether and how the `Engine` will optimize an AST after compilation.
///
/// Not available under the `no_optimize` feature.
#[cfg(not(feature = "no_optimize"))]
pub fn optimization_level(&self) -> OptimizationLevel {
self.optimization_level
}
/// Set the maximum levels of function calls allowed for a script in order to avoid
/// infinite recursion and stack overflows.
#[cfg(not(feature = "unchecked"))]
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pub fn set_max_call_levels(&mut self, levels: usize) -> &mut Self {
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self.limits.max_call_stack_depth = levels;
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self
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}
/// The maximum levels of function calls allowed for a script.
#[cfg(not(feature = "unchecked"))]
pub fn max_call_levels(&self) -> usize {
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self.limits.max_call_stack_depth
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}
/// Set the maximum number of operations allowed for a script to run to avoid
/// consuming too much resources (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
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pub fn set_max_operations(&mut self, operations: u64) -> &mut Self {
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self.limits.max_operations = if operations == u64::MAX {
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0
} else {
operations
};
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self
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}
/// The maximum number of operations allowed for a script to run (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
pub fn max_operations(&self) -> u64 {
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self.limits.max_operations
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}
/// Set the maximum number of imported modules allowed for a script.
#[cfg(not(feature = "unchecked"))]
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pub fn set_max_modules(&mut self, modules: usize) -> &mut Self {
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self.limits.max_modules = modules;
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self
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}
/// The maximum number of imported modules allowed for a script.
#[cfg(not(feature = "unchecked"))]
pub fn max_modules(&self) -> usize {
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self.limits.max_modules
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}
/// Set the depth limits for expressions (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
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pub fn set_max_expr_depths(
&mut self,
max_expr_depth: usize,
max_function_expr_depth: usize,
) -> &mut Self {
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self.limits.max_expr_depth = if max_expr_depth == usize::MAX {
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0
} else {
max_expr_depth
};
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self.limits.max_function_expr_depth = if max_function_expr_depth == usize::MAX {
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0
} else {
max_function_expr_depth
};
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self
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}
/// The depth limit for expressions (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
pub fn max_expr_depth(&self) -> usize {
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self.limits.max_expr_depth
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}
/// The depth limit for expressions in functions (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
pub fn max_function_expr_depth(&self) -> usize {
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self.limits.max_function_expr_depth
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}
/// Set the maximum length of strings (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
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pub fn set_max_string_size(&mut self, max_size: usize) -> &mut Self {
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self.limits.max_string_size = if max_size == usize::MAX { 0 } else { max_size };
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self
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}
/// The maximum length of strings (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
pub fn max_string_size(&self) -> usize {
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self.limits.max_string_size
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}
/// Set the maximum length of arrays (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_index"))]
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pub fn set_max_array_size(&mut self, max_size: usize) -> &mut Self {
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self.limits.max_array_size = if max_size == usize::MAX { 0 } else { max_size };
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self
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}
/// The maximum length of arrays (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_index"))]
pub fn max_array_size(&self) -> usize {
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self.limits.max_array_size
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}
/// Set the maximum length of object maps (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_object"))]
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pub fn set_max_map_size(&mut self, max_size: usize) -> &mut Self {
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self.limits.max_map_size = if max_size == usize::MAX { 0 } else { max_size };
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self
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}
/// The maximum length of object maps (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
#[cfg(not(feature = "no_object"))]
pub fn max_map_size(&self) -> usize {
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self.limits.max_map_size
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}
/// Set the module resolution service used by the `Engine`.
///
/// Not available under the `no_module` feature.
#[cfg(not(feature = "no_module"))]
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pub fn set_module_resolver(
&mut self,
resolver: Option<impl ModuleResolver + 'static>,
) -> &mut Self {
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self.module_resolver = resolver.map(|f| Box::new(f) as Box<dyn ModuleResolver>);
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self
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}
/// Disable a particular keyword or operator in the language.
///
/// # Examples
///
/// The following will raise an error during parsing because the `if` keyword is disabled
/// and is recognized as a variable name!
///
/// ```rust,should_panic
/// # fn main() -> Result<(), rhai::ParseError> {
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// engine.disable_symbol("if"); // disable the 'if' keyword
///
/// engine.compile("let x = if true { 42 } else { 0 };")?;
/// // ^ 'if' is rejected as a reserved keyword
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/// # Ok(())
/// # }
/// ```
///
/// The following will raise an error during parsing because the `+=` operator is disabled.
///
/// ```rust,should_panic
/// # fn main() -> Result<(), rhai::ParseError> {
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// engine.disable_symbol("+="); // disable the '+=' operator
///
/// engine.compile("let x = 42; x += 1;")?;
/// // ^ unknown operator
/// # Ok(())
/// # }
/// ```
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pub fn disable_symbol(&mut self, symbol: &str) -> &mut Self {
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if self.disabled_symbols.is_none() {
self.disabled_symbols = Some(Default::default());
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}
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self.disabled_symbols
.as_mut()
.unwrap()
.insert(symbol.into());
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self
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}
/// Register a custom operator into the language.
///
/// The operator must be a valid identifier (i.e. it cannot be a symbol).
///
/// # Examples
///
/// ```rust
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::{Engine, RegisterFn};
///
/// let mut engine = Engine::new();
///
/// // Register a custom operator called 'foo' and give it
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/// // a precedence of 160 (i.e. between +|- and *|/).
/// engine.register_custom_operator("foo", 160).unwrap();
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///
/// // Register a binary function named 'foo'
/// engine.register_fn("foo", |x: i64, y: i64| (x * y) - (x + y));
///
/// assert_eq!(
/// engine.eval_expression::<i64>("1 + 2 * 3 foo 4 - 5 / 6")?,
/// 15
/// );
/// # Ok(())
/// # }
/// ```
pub fn register_custom_operator(
&mut self,
keyword: &str,
precedence: u8,
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) -> Result<&mut Self, String> {
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if !is_valid_identifier(keyword.chars()) {
return Err(format!("not a valid identifier: '{}'", keyword).into());
}
match Token::lookup_from_syntax(keyword) {
// Standard identifiers, reserved keywords and custom keywords are OK
None | Some(Token::Reserved(_)) | Some(Token::Custom(_)) => (),
// Disabled keywords are also OK
Some(token)
if !self
.disabled_symbols
.as_ref()
.map(|d| d.contains(token.syntax().as_ref()))
.unwrap_or(false) =>
{
()
}
// Active standard keywords cannot be made custom
Some(_) => return Err(format!("'{}' is a reserved keyword", keyword).into()),
}
// Add to custom keywords
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if self.custom_keywords.is_none() {
self.custom_keywords = Some(Default::default());
}
self.custom_keywords
.as_mut()
.unwrap()
.insert(keyword.into(), precedence);
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Ok(self)
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}
}