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//! Module that defines the `call_fn` API of [`Engine`].
#![cfg(not(feature = "no_function"))]
use crate::eval::{Caches, GlobalRuntimeState};
use crate::types::dynamic::Variant;
use crate::{
reify, Dynamic, Engine, FuncArgs, Position, RhaiResult, RhaiResultOf, Scope, StaticVec, AST,
ERR,
};
use std::any::{type_name, TypeId};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
impl Engine {
/// Call a script function defined in an [`AST`] with multiple arguments.
///
/// Not available under `no_function`.
///
/// The [`AST`] is evaluated before calling the function.
/// This allows a script to load the necessary modules.
/// This is usually desired. If not, a specialized [`AST`] can be prepared that contains only
/// function definitions without any body script via [`AST::clear_statements`].
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::{Engine, Scope};
///
/// let engine = Engine::new();
///
/// let ast = engine.compile("
/// fn add(x, y) { len(x) + y + foo }
/// fn add1(x) { len(x) + 1 + foo }
/// fn bar() { foo/2 }
/// ")?;
///
/// let mut scope = Scope::new();
/// scope.push("foo", 42_i64);
///
/// // Call the script-defined function
/// let result = engine.call_fn::<i64>(&mut scope, &ast, "add", ( "abc", 123_i64 ) )?;
/// assert_eq!(result, 168);
///
/// let result = engine.call_fn::<i64>(&mut scope, &ast, "add1", ( "abc", ) )?;
/// // ^^^^^^^^^^ tuple of one
/// assert_eq!(result, 46);
///
/// let result = engine.call_fn::<i64>(&mut scope, &ast, "bar", () )?;
/// assert_eq!(result, 21);
/// # }
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn call_fn<T: Variant + Clone>(
&self,
scope: &mut Scope,
ast: &AST,
name: impl AsRef<str>,
args: impl FuncArgs,
) -> RhaiResultOf<T> {
let mut arg_values = StaticVec::new_const();
args.parse(&mut arg_values);
let result = self.call_fn_raw(scope, ast, true, true, name, None, arg_values)?;
// Bail out early if the return type needs no cast
if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
return Ok(reify!(result => T));
}
if TypeId::of::<T>() == TypeId::of::<()>() {
return Ok(reify!(() => T));
}
// Cast return type
let typ = self.map_type_name(result.type_name());
result.try_cast().ok_or_else(|| {
let t = self.map_type_name(type_name::<T>()).into();
ERR::ErrorMismatchOutputType(t, typ.into(), Position::NONE).into()
})
}
/// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
///
/// The following options are available:
///
/// * whether to evaluate the [`AST`] to load necessary modules before calling the function
/// * whether to rewind the [`Scope`] after the function call
/// * a value for binding to the `this` pointer (if any)
///
/// Not available under `no_function`.
///
/// # WARNING - Low Level API
///
/// This function is very low level.
///
/// # Arguments
///
/// All the arguments are _consumed_, meaning that they're replaced by `()`.
/// This is to avoid unnecessarily cloning the arguments.
///
/// Do not use the arguments after this call. If they are needed afterwards, clone them _before_
/// calling this function.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::{Engine, Scope, Dynamic};
///
/// let engine = Engine::new();
///
/// let ast = engine.compile("
/// fn add(x, y) { len(x) + y + foo }
/// fn add1(x) { len(x) + 1 + foo }
/// fn bar() { foo/2 }
/// fn action(x) { this += x; } // function using 'this' pointer
/// fn decl(x) { let hello = x; } // declaring variables
/// ")?;
///
/// let mut scope = Scope::new();
/// scope.push("foo", 42_i64);
///
/// // Call the script-defined function
/// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "add", None, [ "abc".into(), 123_i64.into() ])?;
/// // ^^^^ no 'this' pointer
/// assert_eq!(result.cast::<i64>(), 168);
///
/// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "add1", None, [ "abc".into() ])?;
/// assert_eq!(result.cast::<i64>(), 46);
///
/// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "bar", None, [])?;
/// assert_eq!(result.cast::<i64>(), 21);
///
/// let mut value = 1_i64.into();
/// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "action", Some(&mut value), [ 41_i64.into() ])?;
/// // ^^^^^^^^^^^^^^^^ binding the 'this' pointer
/// assert_eq!(value.as_int().unwrap(), 42);
///
/// engine.call_fn_raw(&mut scope, &ast, true, false, "decl", None, [ 42_i64.into() ])?;
/// // ^^^^^ do not rewind scope
/// assert_eq!(scope.get_value::<i64>("hello").unwrap(), 42);
/// # }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn call_fn_raw(
&self,
scope: &mut Scope,
ast: &AST,
eval_ast: bool,
rewind_scope: bool,
name: impl AsRef<str>,
this_ptr: Option<&mut Dynamic>,
arg_values: impl AsMut<[Dynamic]>,
) -> RhaiResult {
let mut arg_values = arg_values;
self._call_fn(
scope,
&mut GlobalRuntimeState::new(self),
&mut Caches::new(),
ast,
eval_ast,
rewind_scope,
name.as_ref(),
this_ptr,
arg_values.as_mut(),
)
}
/// _(internals)_ Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
/// Exported under the `internals` feature only.
///
/// The following options are available:
///
/// * whether to evaluate the [`AST`] to load necessary modules before calling the function
/// * whether to rewind the [`Scope`] after the function call
/// * a value for binding to the `this` pointer (if any)
///
/// Not available under `no_function`.
///
/// # WARNING - Unstable API
///
/// This API is volatile and may change in the future.
///
/// # WARNING - Low Level API
///
/// This function is _extremely_ low level.
///
/// A [`GlobalRuntimeState`] and [`Caches`] need to be passed into the function, which can be
/// created via [`GlobalRuntimeState::new`] and [`Caches::new`].
///
/// This makes repeatedly calling particular functions more efficient as the functions
/// resolution cache is kept intact.
///
/// # Arguments
///
/// All the arguments are _consumed_, meaning that they're replaced by `()`. This is to avoid
/// unnecessarily cloning the arguments.
///
/// Do not use the arguments after this call. If they are needed afterwards, clone them _before_
/// calling this function.
#[cfg(feature = "internals")]
#[deprecated = "This API is NOT deprecated, but it is considered volatile and may change in the future."]
#[inline(always)]
pub fn call_fn_raw_raw(
&self,
scope: &mut Scope,
global: &mut GlobalRuntimeState,
caches: &mut Caches,
ast: &AST,
eval_ast: bool,
rewind_scope: bool,
name: &str,
this_ptr: Option<&mut Dynamic>,
arg_values: &mut [Dynamic],
) -> RhaiResult {
self._call_fn(
scope,
global,
caches,
ast,
eval_ast,
rewind_scope,
name,
this_ptr,
arg_values,
)
}
/// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
fn _call_fn(
&self,
scope: &mut Scope,
global: &mut GlobalRuntimeState,
caches: &mut Caches,
ast: &AST,
eval_ast: bool,
rewind_scope: bool,
name: &str,
this_ptr: Option<&mut Dynamic>,
arg_values: &mut [Dynamic],
) -> RhaiResult {
let statements = ast.statements();
let lib = &[ast.as_ref()];
let mut this_ptr = this_ptr;
let orig_scope_len = scope.len();
#[cfg(not(feature = "no_module"))]
let orig_embedded_module_resolver = std::mem::replace(
&mut global.embedded_module_resolver,
ast.resolver().cloned(),
);
let mut result = Ok(Dynamic::UNIT);
if eval_ast && !statements.is_empty() {
result = self.eval_global_statements(scope, global, caches, statements, lib, 0);
if rewind_scope {
scope.rewind(orig_scope_len);
}
}
result = result.and_then(|_| {
let mut args: StaticVec<_> = arg_values.iter_mut().collect();
// Check for data race.
#[cfg(not(feature = "no_closure"))]
crate::func::call::ensure_no_data_race(name, &args, false).map(|_| Dynamic::UNIT)?;
if let Some(fn_def) = ast.shared_lib().get_script_fn(name, args.len()) {
self.call_script_fn(
scope,
global,
caches,
lib,
&mut this_ptr,
fn_def,
&mut args,
rewind_scope,
Position::NONE,
0,
)
} else {
Err(ERR::ErrorFunctionNotFound(name.into(), Position::NONE).into())
}
});
#[cfg(not(feature = "no_module"))]
{
global.embedded_module_resolver = orig_embedded_module_resolver;
}
let result = result?;
#[cfg(feature = "debugging")]
if self.debugger.is_some() {
global.debugger.status = crate::eval::DebuggerStatus::Terminate;
let node = &crate::ast::Stmt::Noop(Position::NONE);
self.run_debugger(scope, global, lib, &mut this_ptr, node, 0)?;
}
Ok(result)
}
}