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//! Module that defines the public compilation API of [`Engine`].
use crate::parser::{ParseResult, ParseState};
use crate::{Engine, Scope, AST};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
impl Engine {
/// Compile a string into an [`AST`], which can be used later for evaluation.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// // Compile a script to an AST and store it for later evaluation
/// let ast = engine.compile("40 + 2")?;
///
/// for _ in 0..42 {
/// assert_eq!(engine.eval_ast::<i64>(&ast)?, 42);
/// }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn compile(&self, script: impl AsRef<str>) -> ParseResult<AST> {
self.compile_with_scope(&Scope::new(), script)
}
/// Compile a string into an [`AST`] using own scope, which can be used later for evaluation.
///
/// ## 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>> {
/// # #[cfg(not(feature = "no_optimize"))]
/// # {
/// use rhai::{Engine, Scope, OptimizationLevel};
///
/// let mut engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push_constant("x", 42_i64); // 'x' is a constant
///
/// // Compile a script to an AST and store it for later evaluation.
/// // Notice that `Full` optimization is on, so constants are folded
/// // into function calls and operators.
/// let ast = engine.compile_with_scope(&mut scope,
/// "if x > 40 { x } else { 0 }" // all 'x' are replaced with 42
/// )?;
///
/// // Normally this would have failed because no scope is passed into the 'eval_ast'
/// // call and so the variable 'x' does not exist. Here, it passes because the script
/// // has been optimized and all references to 'x' are already gone.
/// assert_eq!(engine.eval_ast::<i64>(&ast)?, 42);
/// # }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn compile_with_scope(&self, scope: &Scope, script: impl AsRef<str>) -> ParseResult<AST> {
self.compile_scripts_with_scope(scope, &[script])
}
/// Compile a string into an [`AST`] using own scope, which can be used later for evaluation,
/// embedding all imported modules.
///
/// Not available under `no_module`.
///
/// Modules referred by `import` statements containing literal string paths are eagerly resolved
/// via the current [module resolver][crate::ModuleResolver] and embedded into the resultant
/// [`AST`]. When it is evaluated later, `import` statement directly recall pre-resolved
/// [modules][crate::Module] and the resolution process is not performed again.
#[cfg(not(feature = "no_module"))]
pub fn compile_into_self_contained(
&self,
scope: &Scope,
script: impl AsRef<str>,
) -> crate::RhaiResultOf<AST> {
use crate::{
ast::{ASTNode, Expr, Stmt},
func::native::shared_take_or_clone,
module::resolvers::StaticModuleResolver,
};
use std::collections::BTreeSet;
fn collect_imports(
ast: &AST,
resolver: &StaticModuleResolver,
imports: &mut BTreeSet<crate::Identifier>,
) {
ast._walk(&mut |path| match path.last().unwrap() {
// Collect all `import` statements with a string constant path
ASTNode::Stmt(Stmt::Import(x, ..)) => match x.0 {
Expr::StringConstant(ref s, ..)
if !resolver.contains_path(s)
&& (imports.is_empty() || !imports.contains(s.as_str())) =>
{
imports.insert(s.clone().into());
true
}
_ => true,
},
_ => true,
});
}
let mut ast = self.compile_with_scope(scope, script)?;
let mut resolver = StaticModuleResolver::new();
let mut imports = BTreeSet::new();
collect_imports(&ast, &resolver, &mut imports);
if !imports.is_empty() {
while let Some(path) = imports.pop_first() {
let path = path.clone();
match self
.module_resolver()
.resolve_ast(self, None, &path, crate::Position::NONE)
{
Some(Ok(module_ast)) => collect_imports(&module_ast, &resolver, &mut imports),
Some(err) => return err,
None => (),
}
let module =
self.module_resolver()
.resolve(self, None, &path, crate::Position::NONE)?;
let module = shared_take_or_clone(module);
resolver.insert(path, module);
}
ast.resolver = Some(resolver.into());
}
Ok(ast)
}
/// When passed a list of strings, first join the strings into one large script, and then
/// compile them into an [`AST`] using own scope, which can be used later for evaluation.
///
/// The scope is useful for passing constants into the script for optimization when using
/// [`OptimizationLevel::Full`][crate::OptimizationLevel::Full].
///
/// ## Note
///
/// All strings are simply parsed one after another with nothing inserted in between, not even a
/// newline or space.
///
/// ## 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>> {
/// # #[cfg(not(feature = "no_optimize"))]
/// # {
/// use rhai::{Engine, Scope, OptimizationLevel};
///
/// let mut engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push_constant("x", 42_i64); // 'x' is a constant
///
/// // Compile a script made up of script segments to an AST and store it for later evaluation.
/// // Notice that `Full` optimization is on, so constants are folded
/// // into function calls and operators.
/// let ast = engine.compile_scripts_with_scope(&mut scope, &[
/// "if x > 40", // all 'x' are replaced with 42
/// "{ x } el",
/// "se { 0 }" // segments do not need to be valid scripts!
/// ])?;
///
/// // Normally this would have failed because no scope is passed into the 'eval_ast'
/// // call and so the variable 'x' does not exist. Here, it passes because the script
/// // has been optimized and all references to 'x' are already gone.
/// assert_eq!(engine.eval_ast::<i64>(&ast)?, 42);
/// # }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn compile_scripts_with_scope<S: AsRef<str>>(
&self,
scope: &Scope,
scripts: impl AsRef<[S]>,
) -> ParseResult<AST> {
self.compile_scripts_with_scope_raw(
Some(scope),
scripts,
#[cfg(not(feature = "no_optimize"))]
self.optimization_level,
)
}
/// Join a list of strings and compile into an [`AST`] using own scope at a specific optimization level.
///
/// ## 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.
#[inline]
pub(crate) fn compile_scripts_with_scope_raw<S: AsRef<str>>(
&self,
scope: Option<&Scope>,
scripts: impl AsRef<[S]>,
#[cfg(not(feature = "no_optimize"))] optimization_level: crate::OptimizationLevel,
) -> ParseResult<AST> {
let (stream, tc) = self.lex(scripts.as_ref());
let input = &mut stream.peekable();
let lib = &mut <_>::default();
let state = ParseState::new(scope, input, tc.clone(), lib);
let mut _ast = self.parse(
state,
#[cfg(not(feature = "no_optimize"))]
optimization_level,
)?;
#[cfg(feature = "metadata")]
{
let global_comments = &tc.borrow().global_comments;
_ast.doc = global_comments.into();
}
Ok(_ast)
}
/// Compile a string containing an expression into an [`AST`],
/// which can be used later for evaluation.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// // Compile a script to an AST and store it for later evaluation
/// let ast = engine.compile_expression("40 + 2")?;
///
/// for _ in 0..42 {
/// assert_eq!(engine.eval_ast::<i64>(&ast)?, 42);
/// }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn compile_expression(&self, script: impl AsRef<str>) -> ParseResult<AST> {
self.compile_expression_with_scope(&Scope::new(), script)
}
/// Compile a string containing an expression into an [`AST`] using own scope,
/// which can be used later for evaluation.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_optimize"))]
/// # {
/// use rhai::{Engine, Scope, OptimizationLevel};
///
/// let mut engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push_constant("x", 10_i64); // 'x' is a constant
///
/// // Compile a script to an AST and store it for later evaluation.
/// let ast = engine.compile_expression_with_scope(&mut scope,
/// "2 + (x + x) * 2" // all 'x' are replaced with 10
/// )?;
///
/// // Normally this would have failed because no scope is passed into the 'eval_ast'
/// // call and so the variable 'x' does not exist. Here, it passes because the script
/// // has been optimized and all references to 'x' are already gone.
/// assert_eq!(engine.eval_ast::<i64>(&ast)?, 42);
/// # }
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn compile_expression_with_scope(
&self,
scope: &Scope,
script: impl AsRef<str>,
) -> ParseResult<AST> {
let scripts = [script];
let (stream, t) = self.lex(&scripts);
let input = &mut stream.peekable();
let lib = &mut <_>::default();
let state = ParseState::new(Some(scope), input, t, lib);
self.parse_global_expr(
state,
|_| {},
#[cfg(not(feature = "no_optimize"))]
self.optimization_level,
)
}
}