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//! Module defining the public API of the Rhai engine.
pub mod eval;
pub mod run;
pub mod compile;
pub mod json;
pub mod files;
pub mod register;
pub mod call_fn;
pub mod options;
pub mod optimize;
pub mod limits;
pub mod events;
pub mod formatting;
pub mod custom_syntax;
pub mod build_type;
#[cfg(feature = "metadata")]
pub mod definitions;
pub mod deprecated;
use crate::func::{locked_read, locked_write, Locked};
use crate::types::StringsInterner;
use crate::{Dynamic, Engine, Identifier};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
/// Default limits.
pub mod default_limits {
#[cfg(not(feature = "unchecked"))]
#[cfg(feature = "internals")]
pub use super::limits::default_limits::*;
/// Maximum number of parameters in functions with [`Dynamic`][crate::Dynamic] support.
pub const MAX_DYNAMIC_PARAMETERS: usize = 16;
/// Maximum number of strings interned.
pub const MAX_STRINGS_INTERNED: usize = 256;
}
impl Engine {
/// Set the maximum number of strings to be interned.
#[inline(always)]
pub fn set_max_strings_interned(&mut self, max: usize) -> &mut Self {
if max == 0 {
self.interned_strings = None;
} else if let Some(ref interner) = self.interned_strings {
if let Some(mut guard) = locked_write(interner) {
guard.set_max(max);
}
} else {
self.interned_strings = Some(Locked::new(StringsInterner::new(max)));
}
self
}
/// The maximum number of strings to be interned.
#[inline(always)]
#[must_use]
pub fn max_strings_interned(&self) -> usize {
self.interned_strings.as_ref().map_or(0, |interner| {
locked_read(interner).map_or(0, |guard| guard.max())
})
}
/// The module resolution service used by the [`Engine`].
///
/// Not available under `no_module`.
#[cfg(not(feature = "no_module"))]
#[inline(always)]
#[must_use]
pub fn module_resolver(&self) -> &dyn crate::ModuleResolver {
static DUMMY_RESOLVER: crate::module::resolvers::DummyModuleResolver =
crate::module::resolvers::DummyModuleResolver;
self.module_resolver.as_deref().unwrap_or(&DUMMY_RESOLVER)
}
/// Set the module resolution service used by the [`Engine`].
///
/// Not available under `no_module`.
#[cfg(not(feature = "no_module"))]
#[inline(always)]
pub fn set_module_resolver(
&mut self,
resolver: impl crate::ModuleResolver + 'static,
) -> &mut Self {
self.module_resolver = Some(Box::new(resolver));
self
}
/// 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 reserved symbol!
///
/// ```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 symbol
/// # 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(())
/// # }
/// ```
#[inline]
pub fn disable_symbol(&mut self, symbol: impl Into<Identifier>) -> &mut Self {
self.disabled_symbols.insert(symbol.into());
self
}
/// Is a particular keyword or operator disabled?
///
/// # Examples
///
/// ```rust
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// engine.disable_symbol("if"); // disable the 'if' keyword
///
/// assert!(engine.is_symbol_disabled("if"));
/// ```
#[inline(always)]
#[must_use]
pub fn is_symbol_disabled(&self, symbol: &str) -> bool {
self.disabled_symbols.contains(symbol)
}
/// Register a custom operator with a precedence into the language.
///
/// Not available under `no_custom_syntax`.
///
/// The operator can be a valid identifier, a reserved symbol, a disabled operator or a disabled keyword.
///
/// The precedence cannot be zero.
///
/// # Example
///
/// ```rust
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let mut engine = Engine::new();
///
/// // Register a custom operator called '#' and give it
/// // a precedence of 160 (i.e. between +|- and *|/).
/// engine.register_custom_operator("#", 160).expect("should succeed");
///
/// // Register a binary function named '#'
/// engine.register_fn("#", |x: i64, y: i64| (x * y) - (x + y));
///
/// assert_eq!(
/// engine.eval_expression::<i64>("1 + 2 * 3 # 4 - 5 / 6")?,
/// 15
/// );
/// # Ok(())
/// # }
/// ```
#[cfg(not(feature = "no_custom_syntax"))]
pub fn register_custom_operator(
&mut self,
keyword: impl AsRef<str>,
precedence: u8,
) -> Result<&mut Self, String> {
use crate::tokenizer::Token;
let precedence = crate::engine::Precedence::new(precedence)
.ok_or_else(|| "precedence cannot be zero".to_string())?;
let keyword = keyword.as_ref();
match Token::lookup_symbol_from_syntax(keyword) {
// Standard identifiers and reserved keywords are OK
None | Some(Token::Reserved(..)) => (),
// custom keywords are OK
#[cfg(not(feature = "no_custom_syntax"))]
Some(Token::Custom(..)) => (),
// Active standard keywords cannot be made custom
// Disabled keywords are OK
Some(token)
if token.is_standard_keyword()
&& !self.is_symbol_disabled(token.literal_syntax()) =>
{
return Err(format!("'{keyword}' is a reserved keyword"))
}
// Active standard symbols cannot be made custom
Some(token)
if token.is_standard_symbol()
&& !self.is_symbol_disabled(token.literal_syntax()) =>
{
return Err(format!("'{keyword}' is a reserved operator"))
}
// Active standard symbols cannot be made custom
Some(token) if !self.is_symbol_disabled(token.literal_syntax()) => {
return Err(format!("'{keyword}' is a reserved symbol"))
}
// Disabled symbols are OK
Some(_) => (),
}
// Add to custom keywords
self.custom_keywords
.insert(keyword.into(), Some(precedence));
Ok(self)
}
/// Get the default value of the custom state for each evaluation run.
#[inline(always)]
pub const fn default_tag(&self) -> &Dynamic {
&self.def_tag
}
/// Get a mutable reference to the default value of the custom state for each evaluation run.
#[inline(always)]
pub fn default_tag_mut(&mut self) -> &mut Dynamic {
&mut self.def_tag
}
/// Set the default value of the custom state for each evaluation run.
#[inline(always)]
pub fn set_default_tag(&mut self, value: impl Into<Dynamic>) -> &mut Self {
self.def_tag = value.into();
self
}
}