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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::{
Dynamic, Engine, FnArgsVec, FuncArgs, Position, RhaiResult, RhaiResultOf, Scope, AST, ERR,
};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
use std::{any::type_name, mem};
/// Options for calling a script-defined function via [`Engine::call_fn_with_options`].
#[derive(Debug, Hash)]
#[non_exhaustive]
pub struct CallFnOptions<'t> {
/// A value for binding to the `this` pointer (if any). Default [`None`].
pub this_ptr: Option<&'t mut Dynamic>,
/// The custom state of this evaluation run (if any), overrides [`Engine::default_tag`]. Default [`None`].
pub tag: Option<Dynamic>,
/// Evaluate the [`AST`] to load necessary modules before calling the function? Default `true`.
pub eval_ast: bool,
/// Rewind the [`Scope`] after the function call? Default `true`.
pub rewind_scope: bool,
/// Call functions in all namespaces instead of only scripted functions within the [`AST`].
pub in_all_namespaces: bool,
}
impl Default for CallFnOptions<'_> {
#[inline(always)]
fn default() -> Self {
Self::new()
}
}
impl<'a> CallFnOptions<'a> {
/// Create a default [`CallFnOptions`].
#[inline(always)]
#[must_use]
pub fn new() -> Self {
Self {
this_ptr: None,
tag: None,
eval_ast: true,
rewind_scope: true,
in_all_namespaces: false,
}
}
/// Bind to the `this` pointer.
#[inline(always)]
#[must_use]
pub fn bind_this_ptr(mut self, value: &'a mut Dynamic) -> Self {
self.this_ptr = Some(value);
self
}
/// Set the custom state of this evaluation run (if any).
#[inline(always)]
#[must_use]
pub fn with_tag(mut self, value: impl Variant + Clone) -> Self {
self.tag = Some(Dynamic::from(value));
self
}
/// Set whether to evaluate the [`AST`] to load necessary modules before calling the function.
#[inline(always)]
#[must_use]
pub const fn eval_ast(mut self, value: bool) -> Self {
self.eval_ast = value;
self
}
/// Set whether to rewind the [`Scope`] after the function call.
#[inline(always)]
#[must_use]
pub const fn rewind_scope(mut self, value: bool) -> Self {
self.rewind_scope = value;
self
}
/// Call functions in all namespaces instead of only scripted functions within the [`AST`].
#[inline(always)]
#[must_use]
pub const fn in_all_namespaces(mut self, value: bool) -> Self {
self.in_all_namespaces = value;
self
}
}
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, use [`call_fn_with_options`][Engine::call_fn_with_options] instead.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// 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(always)]
pub fn call_fn<T: Variant + Clone>(
&self,
scope: &mut Scope,
ast: &AST,
fn_name: impl AsRef<str>,
args: impl FuncArgs,
) -> RhaiResultOf<T> {
self.call_fn_with_options(<_>::default(), scope, ast, fn_name, args)
}
/// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
/// Options are provided via the [`CallFnOptions`] type.
///
/// If [`in_all_namespaces`](CallFnOptions::in_all_namespaces) is specified, the function will
/// be searched in all namespaces instead, so registered native Rust functions etc. are also found.
///
/// This is an advanced API.
///
/// Not available under `no_function`.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// use rhai::{Engine, Scope, Dynamic, CallFnOptions};
///
/// let engine = Engine::new();
///
/// let ast = engine.compile("
/// 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);
///
/// // Binding the 'this' pointer
/// let mut value = 1_i64.into();
/// let options = CallFnOptions::new().bind_this_ptr(&mut value);
///
/// engine.call_fn_with_options(options, &mut scope, &ast, "action", ( 41_i64, ))?;
/// assert_eq!(value.as_int().unwrap(), 42);
///
/// // Do not rewind scope
/// let options = CallFnOptions::default().rewind_scope(false);
///
/// engine.call_fn_with_options(options, &mut scope, &ast, "decl", ( 42_i64, ))?;
/// assert_eq!(scope.get_value::<i64>("hello").unwrap(), 42);
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn call_fn_with_options<T: Variant + Clone>(
&self,
options: CallFnOptions,
scope: &mut Scope,
ast: &AST,
fn_name: impl AsRef<str>,
args: impl FuncArgs,
) -> RhaiResultOf<T> {
let mut arg_values = FnArgsVec::new_const();
args.parse(&mut arg_values);
self._call_fn(
options,
scope,
ast,
fn_name.as_ref(),
arg_values.as_mut(),
&mut self.new_global_runtime_state(),
&mut Caches::new(),
)
.and_then(|result| {
result.try_cast_result().map_err(|r| {
let result_type = self.map_type_name(r.type_name());
let cast_type = match type_name::<T>() {
typ if typ.contains("::") => self.map_type_name(typ),
typ => typ,
};
ERR::ErrorMismatchOutputType(cast_type.into(), result_type.into(), Position::NONE)
.into()
})
})
}
/// Make a function call with multiple [`Dynamic`] arguments.
///
/// # 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.
#[inline(always)]
pub(crate) fn _call_fn(
&self,
options: CallFnOptions,
scope: &mut Scope,
ast: &AST,
name: &str,
arg_values: &mut [Dynamic],
global: &mut GlobalRuntimeState,
caches: &mut Caches,
) -> RhaiResult {
let statements = ast.statements();
let orig_source = mem::replace(&mut global.source, ast.source_raw().cloned());
let orig_lib_len = global.lib.len();
global.lib.push(ast.shared_lib().clone());
let orig_tag = options.tag.map(|v| mem::replace(&mut global.tag, v));
let mut this_ptr = options.this_ptr;
#[cfg(not(feature = "no_module"))]
let orig_embedded_module_resolver =
std::mem::replace(&mut global.embedded_module_resolver, ast.resolver.clone());
let rewind_scope = options.rewind_scope;
let in_all_namespaces = options.in_all_namespaces;
defer! { global => move |g| {
#[cfg(not(feature = "no_module"))]
{
g.embedded_module_resolver = orig_embedded_module_resolver;
}
if let Some(orig_tag) = orig_tag { g.tag = orig_tag; }
g.lib.truncate(orig_lib_len);
g.source = orig_source;
}}
let global_result = if options.eval_ast && !statements.is_empty() {
defer! {
scope if rewind_scope => rewind;
let orig_scope_len = scope.len();
}
self.eval_global_statements(global, caches, scope, statements, true)
} else {
Ok(Dynamic::UNIT)
};
let result = global_result.and_then(|_| {
let args = &mut arg_values.iter_mut().collect::<FnArgsVec<_>>();
// Check for data race.
#[cfg(not(feature = "no_closure"))]
crate::func::ensure_no_data_race(name, args, false)?;
if let Some(fn_def) = ast.shared_lib().get_script_fn(name, args.len()) {
self.call_script_fn(
global,
caches,
scope,
this_ptr.as_deref_mut(),
None,
fn_def,
args,
rewind_scope,
Position::NONE,
)
.or_else(|err| match *err {
ERR::Exit(out, ..) => Ok(out),
_ => Err(err),
})
} else if !in_all_namespaces {
Err(ERR::ErrorFunctionNotFound(name.into(), Position::NONE).into())
} else {
let has_this = this_ptr.as_deref_mut().map_or(false, |this_ptr| {
args.insert(0, this_ptr);
true
});
self.eval_fn_call_with_arguments::<Dynamic>(name, args, has_this, has_this)
}
});
#[cfg(feature = "debugging")]
if self.is_debugger_registered() {
global.debugger_mut().status = crate::eval::DebuggerStatus::Terminate;
let node = &crate::ast::Stmt::Noop(Position::NONE);
self.dbg(global, caches, scope, this_ptr, node)?;
}
result.map_err(|err| match *err {
ERR::ErrorInFunctionCall(fn_name, _, inner_err, _) if fn_name == name => inner_err,
_ => err,
})
}
}