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//! Module that defines the public file-based API of [`Engine`].
#![cfg(not(feature = "no_std"))]
#![cfg(any(not(target_family = "wasm"), not(target_os = "unknown")))]
use crate::types::dynamic::Variant;
use crate::{Engine, RhaiResultOf, Scope, AST, ERR};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
use std::{
fs::File,
io::Read,
path::{Path, PathBuf},
};
impl Engine {
/// Read the contents of a file into a string.
fn read_file(path: impl AsRef<Path>) -> RhaiResultOf<String> {
let path = path.as_ref();
let mut f = File::open(path).map_err(|err| {
ERR::ErrorSystem(
format!("Cannot open script file '{}'", path.to_string_lossy()),
err.into(),
)
})?;
let mut contents = String::new();
f.read_to_string(&mut contents).map_err(|err| {
ERR::ErrorSystem(
format!("Cannot read script file '{}'", path.to_string_lossy()),
err.into(),
)
})?;
if contents.starts_with("#!") {
// Remove shebang
match contents.find('\n') {
Some(n) => {
contents.drain(0..n).count();
}
None => contents.clear(),
}
}
Ok(contents)
}
/// Compile a script file into an [`AST`], which can be used later for evaluation.
///
/// Not available under `no_std` or `WASM`.
///
/// # Example
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// // Compile a script file to an AST and store it for later evaluation.
/// // Notice that a PathBuf is required which can easily be constructed from a string.
/// let ast = engine.compile_file("script.rhai".into())?;
///
/// for _ in 0..42 {
/// engine.eval_ast::<i64>(&ast)?;
/// }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn compile_file(&self, path: PathBuf) -> RhaiResultOf<AST> {
self.compile_file_with_scope(&Scope::new(), path)
}
/// Compile a script file into an [`AST`] using own scope, which can be used later for evaluation.
///
/// Not available under `no_std` or `WASM`.
///
/// ## 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
///
/// ```no_run
/// # 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 a PathBuf is required which can easily be constructed from a string.
/// let ast = engine.compile_file_with_scope(&scope, "script.rhai".into())?;
///
/// let result = engine.eval_ast::<i64>(&ast)?;
/// # }
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn compile_file_with_scope(&self, scope: &Scope, path: PathBuf) -> RhaiResultOf<AST> {
Self::read_file(&path).and_then(|contents| {
let mut ast = self.compile_with_scope(scope, contents)?;
ast.set_source(path.to_string_lossy().as_ref());
Ok(ast)
})
}
/// Evaluate a script file, returning the result value or an error.
///
/// Not available under `no_std` or `WASM`.
///
/// # Example
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// // Notice that a PathBuf is required which can easily be constructed from a string.
/// let result = engine.eval_file::<i64>("script.rhai".into())?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn eval_file<T: Variant + Clone>(&self, path: PathBuf) -> RhaiResultOf<T> {
Self::read_file(path).and_then(|contents| self.eval::<T>(&contents))
}
/// Evaluate a script file with own scope, returning the result value or an error.
///
/// Not available under `no_std` or `WASM`.
///
/// ## 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
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::{Engine, Scope};
///
/// let engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push("x", 42_i64);
///
/// // Notice that a PathBuf is required which can easily be constructed from a string.
/// let result = engine.eval_file_with_scope::<i64>(&mut scope, "script.rhai".into())?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn eval_file_with_scope<T: Variant + Clone>(
&self,
scope: &mut Scope,
path: PathBuf,
) -> RhaiResultOf<T> {
Self::read_file(path).and_then(|contents| self.eval_with_scope(scope, &contents))
}
/// Evaluate a file.
///
/// Not available under `no_std` or `WASM`.
///
/// # Example
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// // Notice that a PathBuf is required which can easily be constructed from a string.
/// engine.run_file("script.rhai".into())?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn run_file(&self, path: PathBuf) -> RhaiResultOf<()> {
Self::read_file(path).and_then(|contents| self.run(&contents))
}
/// Evaluate a file with own scope.
///
/// Not available under `no_std` or `WASM`.
///
/// ## 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
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::{Engine, Scope};
///
/// let engine = Engine::new();
///
/// // Create initialized scope
/// let mut scope = Scope::new();
/// scope.push("x", 42_i64);
///
/// // Notice that a PathBuf is required which can easily be constructed from a string.
/// engine.run_file_with_scope(&mut scope, "script.rhai".into())?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn run_file_with_scope(&self, scope: &mut Scope, path: PathBuf) -> RhaiResultOf<()> {
Self::read_file(path).and_then(|contents| self.run_with_scope(scope, &contents))
}
}
/// Evaluate a script file, returning the result value or an error.
///
/// Not available under `no_std` or `WASM`.
///
/// # Example
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// let result = rhai::eval_file::<i64>("script.rhai")?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn eval_file<T: Variant + Clone>(path: impl AsRef<Path>) -> RhaiResultOf<T> {
Engine::read_file(path).and_then(|contents| Engine::new().eval::<T>(&contents))
}
/// Evaluate a file.
///
/// Not available under `no_std` or `WASM`.
///
/// # Example
///
/// ```no_run
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// rhai::run_file("script.rhai")?;
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn run_file(path: impl AsRef<Path>) -> RhaiResultOf<()> {
Engine::read_file(path).and_then(|contents| Engine::new().run(&contents))
}