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//! Module that defines the public evaluation API of [`Engine`].
use crate::engine::{EvalState, Imports};
use crate::parser::ParseState;
use crate::types::dynamic::Variant;
use crate::{Dynamic, Engine, EvalAltResult, Module, Position, RhaiResult, Scope, AST};
use std::any::type_name;
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
impl Engine {
/// Evaluate a string.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use quad_compat_rhai::Engine;
///
/// let engine = Engine::new();
///
/// assert_eq!(engine.eval::<i64>("40 + 2")?, 42);
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn eval<T: Variant + Clone>(&self, script: &str) -> Result<T, Box<EvalAltResult>> {
self.eval_with_scope(&mut Scope::new(), script)
}
/// Evaluate a string with own scope.
///
/// ## Constants Propagation
///
/// If not [`OptimizationLevel::None`][crate::OptimizationLevel::None], constants defined within
/// the scope are propagated throughout the script _including_ functions. This allows functions
/// to be optimized based on dynamic global constants.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use quad_compat_rhai::{Engine, Scope};
///
/// let engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push("x", 40_i64);
///
/// assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x += 2; x")?, 42);
/// assert_eq!(engine.eval_with_scope::<i64>(&mut scope, "x += 2; x")?, 44);
///
/// // The variable in the scope is modified
/// assert_eq!(scope.get_value::<i64>("x").expect("variable x should exist"), 44);
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn eval_with_scope<T: Variant + Clone>(
&self,
scope: &mut Scope,
script: &str,
) -> Result<T, Box<EvalAltResult>> {
let ast = self.compile_with_scope_and_optimization_level(
scope,
&[script],
#[cfg(not(feature = "no_optimize"))]
self.optimization_level,
)?;
self.eval_ast_with_scope(scope, &ast)
}
/// Evaluate a string containing an expression.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use quad_compat_rhai::Engine;
///
/// let engine = Engine::new();
///
/// assert_eq!(engine.eval_expression::<i64>("40 + 2")?, 42);
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn eval_expression<T: Variant + Clone>(
&self,
script: &str,
) -> Result<T, Box<EvalAltResult>> {
self.eval_expression_with_scope(&mut Scope::new(), script)
}
/// Evaluate a string containing an expression with own scope.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use quad_compat_rhai::{Engine, Scope};
///
/// let engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push("x", 40_i64);
///
/// assert_eq!(engine.eval_expression_with_scope::<i64>(&mut scope, "x + 2")?, 42);
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn eval_expression_with_scope<T: Variant + Clone>(
&self,
scope: &mut Scope,
script: &str,
) -> Result<T, Box<EvalAltResult>> {
let scripts = [script];
let (stream, tokenizer_control) =
self.lex_raw(&scripts, self.token_mapper.as_ref().map(Box::as_ref));
let mut state = ParseState::new(self, tokenizer_control);
// No need to optimize a lone expression
let ast = self.parse_global_expr(
&mut stream.peekable(),
&mut state,
scope,
#[cfg(not(feature = "no_optimize"))]
crate::OptimizationLevel::None,
)?;
self.eval_ast_with_scope(scope, &ast)
}
/// Evaluate an [`AST`].
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use quad_compat_rhai::Engine;
///
/// let engine = Engine::new();
///
/// // Compile a script to an AST and store it for later evaluation
/// let ast = engine.compile("40 + 2")?;
///
/// // Evaluate it
/// assert_eq!(engine.eval_ast::<i64>(&ast)?, 42);
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn eval_ast<T: Variant + Clone>(&self, ast: &AST) -> Result<T, Box<EvalAltResult>> {
self.eval_ast_with_scope(&mut Scope::new(), ast)
}
/// Evaluate an [`AST`] with own scope.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use quad_compat_rhai::{Engine, Scope};
///
/// let engine = Engine::new();
///
/// // Compile a script to an AST and store it for later evaluation
/// let ast = engine.compile("x + 2")?;
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push("x", 40_i64);
///
/// // Compile a script to an AST and store it for later evaluation
/// let ast = engine.compile("x += 2; x")?;
///
/// // Evaluate it
/// assert_eq!(engine.eval_ast_with_scope::<i64>(&mut scope, &ast)?, 42);
/// assert_eq!(engine.eval_ast_with_scope::<i64>(&mut scope, &ast)?, 44);
///
/// // The variable in the scope is modified
/// assert_eq!(scope.get_value::<i64>("x").expect("variable x should exist"), 44);
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn eval_ast_with_scope<T: Variant + Clone>(
&self,
scope: &mut Scope,
ast: &AST,
) -> Result<T, Box<EvalAltResult>> {
let mods = &mut Imports::new();
let result = self.eval_ast_with_scope_raw(scope, mods, ast, 0)?;
let typ = self.map_type_name(result.type_name());
result.try_cast::<T>().ok_or_else(|| {
EvalAltResult::ErrorMismatchOutputType(
self.map_type_name(type_name::<T>()).into(),
typ.into(),
Position::NONE,
)
.into()
})
}
/// Evaluate an [`AST`] with own scope.
#[inline]
pub(crate) fn eval_ast_with_scope_raw<'a>(
&self,
scope: &mut Scope,
mods: &mut Imports,
ast: &'a AST,
level: usize,
) -> RhaiResult {
let mut state = EvalState::new();
if ast.source_raw().is_some() {
mods.source = ast.source_raw().cloned();
}
#[cfg(not(feature = "no_module"))]
{
mods.embedded_module_resolver = ast.resolver().cloned();
}
let statements = ast.statements();
if statements.is_empty() {
return Ok(Dynamic::UNIT);
}
let lib = [
#[cfg(not(feature = "no_function"))]
ast.as_ref(),
];
let lib = if lib.first().map(|m: &&Module| m.is_empty()).unwrap_or(true) {
&lib[0..0]
} else {
&lib
};
self.eval_global_statements(scope, mods, &mut state, statements, lib, level)
}
}